Interactions of Native Cyclodextrins with Metal Ions and Inorganic

Review Cite This: Chem. Rev. 2017, 117, 13461-13501

pubs.acs.org/CR

Interactions of Native Cyclodextrins with Metal Ions and Inorganic Nanoparticles: Fertile Landscape for Chemistry and Materials Science Daniel Prochowicz,†,§ Arkadiusz Kornowicz,‡,§ and Janusz Lewiński*,†,‡ †

Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland

‡

ABSTRACT: Readily available cyclodextrins (CDs) with an inherent hydrophobic internal cavity and hydrophilic external surface are macrocyclic entities that display a combination of molecular recognition and complexation properties with vital implications for host−guest supramolecular chemistry. While the host−guest chemistry of CDs has been widely recognized and led to their exploitation in a variety of important functions over the last five decades, these naturally occurring macrocyclic systems have emerged only recently as promising macrocyclic molecules to fabricate environmentally benign functional nanomaterials. This review surveys the development in the field paying special attention to the synthesis and emerging uses of various unmodified CD− metal complexes and CD−inorganic nanoparticle systems and identifies possible future directions. The association of a hydrophobic cavity of CDs with metal ions or various inorganic nanoparticles is a very appealing strategy for controlling the inorganic subunits properties in the very competitive water environment. In this review we provide the most prominent examples of unmodified CDs’ inclusion complexes with organometallic guests and update the research in this field from the past decade. We discuss also the coordination flexibility of native CDs to metal ions in CD-based metal complexes and summarize the progress in the synthesis and characterization of CD−metal complexes and their use in catalysis and sensing as well as construction of molecular magnets. Then we provide a comprehensive overview of emerging applications of native CDs in materials science and nanotechnology. Remarkably, in the past few years CDs have appeared as attractive building units for the synthesis of carbohydrate metal−organic frameworks (CD−MOFs) in a combination of alkali-metal cations. The preparation of this new class of highly porous materials and their applications in the separation of small molecules, the loading of drug molecules, as well as efficient host templates in the construction of nanomaterials with the desired functionality, including the first-in-class devices including sensors and memristors, are highlighted. Finally, CDs as well-known “green” molecular hosts have also been used as ideal functional molecules to improve the solubility, stability, and bioavailability of inorganic nanoparticles. In this regard, we demonstrate various strategies for the preparation of native CDs-modified inorganic nanomaterials such as metal, metal oxide, and semiconductor and magnetic nanoparticles, aiming to take advantage of both the controlled properties of the inorganic core and the controlled properties of the coating molecules. The functionalization of a CD hydrophobic cavity with an inorganic nanoparticle is very prospective for the development of novel catalytic systems and new tools for highly selective and sensitive sensing platforms for various targets.

CONTENTS 1. Introduction 2. Inclusion Complexes of Native Cyclodextrins with Organometallics and Coordination Compounds 3. Metal Ion Complexes with Unmodified Cyclodextrins 3.1. Studies on the Composition of Native CD− Metal Complexes in Solution 3.2. Structurally Well-Defined Native CD−Metal Complexes 3.2.1. Homometallic Complexes 3.2.2. Heterometallic Complexes 3.3. Supramolecular Architectures of CD−Metal Complexes 3.4. Unmodified CD−Metal Complexes in Catalysis and Sensing

© 2017 American Chemical Society

3.5. Molecular Magnetic Materials as an Emerging Application of CD−Metal Complexes 4. CD-Based Metal−Organic Frameworks 4.1. Structural Diversity of CD−MOFs 4.2. Advanced Functional Materials Based on CD−MOFs 4.2.1. Small Molecules Adsorption and Separation 4.2.2. Molecular Recognition and Sensing 4.2.3. CD−MOFs as Host Template to Metal and Metal Oxide Nanoclusters or Nanoparticles 4.2.4. Memory Devices 4.2.5. CD−MOFs-Based Drug Delivery Systems

13462 13465 13469 13470 13471 13471 13472 13474 13476

13477 13478 13478 13480 13481 13481

13482 13482 13482

Received: May 4, 2017 Published: October 19, 2017 13461

DOI: 10.1021/acs.chemrev.7b00231 Chem. Rev. 2017, 117, 13461−13501

Chemical Reviews 5. Native Cyclodextrins as Stabilizers for Metal Nanoparticle Colloids 5.1. Synthetic Methods of Metal Nanoparticles Stabilized by Native CDs 5.2. Applications of Metal Nanoparticles Stabilized by Native CDs 5.2.1. Catalysis 5.2.2. Sensing 6. Preparation and Application of Native Cyclodextrins-Modified Semiconductor and Magnetic Nanoparticles 6.1. Semiconductor Nanocrystals Coated by Native CDs 6.2. Magnetic Nanoparticles Coated by Native CDs 7. Conclusions and Outlooks Author Information Corresponding Author ORCID Author Contributions Notes Biographies Acknowledgments References

Review

1. INTRODUCTION The self-assembly of molecular systems into highly ordered nanostructured functional assemblies through supramoleculardriven interactions has recently received increasing interest in various fields of chemistry and materials science.1,2 Macrocyclic organic molecules (crown ethers,3,4 cryptands,5 calixarenes,6 cucurbiturils7) have frequently been used as building blocks for self-assembled structures, particularly by acting as efficient host molecules in host−guest chemistry where one or more “guest” molecules are reversibly bound to a “host” cavity. Among the various organic macrocycles, native and modified cyclodextrins (CDs) are the class of particularly interesting host molecules with inherent hydrophobic internal cavity and hydrophilic external surface, and they have long been recognized as sites for host/guest interactions.8−10 Cyclodextrins have been attracting immense attention from the scientific community for decades. They are readily available, harmless, and capable to form sophisticated molecular and supramolecular structures in aqueous environment as well as in the solid state. This interest toward CDs is additionally strongly motivated by their numerous potential applications. Cyclodextrins are cyclic oligomers of D-(+)-glucopyranosyl units linked by α-1,4-glycosidic bonds. For the first time, cyclodextrins were obtained from the enzymatic degradation of starch in 189111 and identified by Schardinger as as cyclic oligosaccharides in 1904.12 However, the real development of research on this group of macrocyclic compounds took place in

13483 13483 13486 13486 13486

13487 13487 13491 13491 13492 13492 13492 13492 13492 13492 13493 13493

Figure 1. Schematic representation of the most commonly observed CD supramolecular assemblies and the corresponding structural examples: (a and b) cage-type assembly embodied by a α-CD/methanol host−guest system, (c and d) head-to-tail channel-type assembly embodied by an inclusion complex of β-CD with trans-cinnamic acid, and (e and f) layer-type assembly embodied by an inclusion complex of α-CD with pnitrophenol. 13462


Chemical Reviews

Review

Figure 2. Schematic representation of (a) a structure and space-filling view of N-heterocyclic carbine (NHC)-capped β-CD-based complex (Reprinted with permission from ref 42. Copyright 2011 John Wiley & Sons.). (b) Model of the hydrogenase enzyme active site within CDs. (c) Supramolecular CD-based [2]-rotaxane polymer (Reprinted with permission from ref 72. Copyright 2006 American Chemical Society.), and (d) ionic self-assembly of cationic α-CD-based pseudorotaxane units and anionic PW11VO404− clusters into 2D supramolecular framework (Reprinted with permission from ref 73. Copyright 2016 Nature Publishing Group.).

Scheme 1. Representation of α-, β-, and γ-CDs and the Truncated Cone Shape of CDs Molecules

the 1980s with the first applications in the pharmaceutical and food industries.13 Produced from a renewable natural material, readily available α-, β-, and γ-CDs are cyclic oligosaccharides comprising six, seven, or eight glucose units, respectively. Due to the chair conformation of the glucopyranose units, CD molecules are shaped like cones with secondary hydroxyl groups extending from the wider edge and the primary groups from the narrow edge (Scheme 1). The cavity size of α-, β-, and γ-CDs increases with increasing number of glucopyranose repeating units, and the cavity diameter is about 0.49, 0.62, and 0.80 nm, respectively. This gives CD molecules a relatively hydrophobic central cavity and a hydrophilic outer surface. Moreover, CDs can be easily chemically modified to selectively

introduce functionality on the primary and secondary faces, and exhaustive reviews dedicated to the chemical CD modification have been reported.14−16 The most notable feature of native and modified CDs is their ability to form molecular inclusion complexes both in solution and in the solid state, in which each guest molecule is surrounded by the hydrophobic environment of the CD cavity.17 The driving forces responsible for inclusion complexes formation have been attributed to many factors such as the extrusion of water from the cavity, van der Waals and hydrophobic interactions, hydrogen bonding, release of conformational strain, and charge-transfer interactions. Notably, the included guest molecule acquired new apparent 13463


Chemical Reviews

Review

zenes.76,77 For example, trans-azobenzene is able to enter the hydrophobic cavity of α-CD in water environment forming a 1:1 host−guest complex.78 UV irradiation induces trans-to-cis isomerization of azobenzene, which leads to the disassembly of the supramolecular complexes.79 This feature has been widely utilized for the generation of light-responsive drug delivery systems.80,81 More recently, red-light-responsive supramolecular valves constructed by tetra-o-methoxy-substituted azobenzene (mAzo) and β-CD were used to control drug release from mesoporous silica nanoparticles (Figure 3).82 The authors

physicochemical and biological properties in comparison with its free molecular state. There are essentially three commonly observed types of supramolecular assemblies in the solid state, i.e., cage, channel, and layer as shown in Figure 1 and which are discussed in detail by Harata.18 The type of packing modes of crystal structures of CD inclusion complexes is largely determined by the size of guest molecules. The cage-type supramolecular assembly is usually observed for relatively small guest molecules, which can be enclosed in the host cavity. For example, in the case of a α-CD/methanol host−guest system shown in Figure 1a and 1b, one methanol molecule is enclosed within the α-CD cavity forming a herringbone fashion in which both ends of the host cavity are closed by adjacent molecules to create an isolated “cage”.19 The channel-type structure is formed by linear stacking of CD macrocycle rings (Figure 1c), which is commonly mediated by long molecules such as alkyl chains or linear polymers, e.g., the inclusion complexes of β-CD with poly(propylene glycol)20 or trans-cinnamic acid (Figure 1d).21 The layer-type packing structures are encountered when the guest molecule is only partially included in the host cavity (Figure 1e). For instance, as shown in Figure 1f, in the supramolecular structure of the 1:1 inclusion complex of α-CD with p-nitrophenol CD rings are arranged in a brickwork pattern to form a layer-type structure in which the adjacent layers are shifted to each other by one-half a CD molecule.22 Nowadays, the capability of cyclodextins to act as hosts and form stable inclusion complexes with hydrophobic guests has led to their exploitation in a variety of important functions in a broad range of research activities. Both native and functionalized CDs are widely used in domains as different as drug delivery carriers,23−30 molecular recognition receptors,31 regioand stereoselective organic synthesis and catalysis32−41 (for an example, see Figure 2a),42 scaffolds for biomimetics for the modeling of metalloenzyme active sites (for a representative example see Figure 2b),43−49 self-healing and bioactive materials,50,51 novel sensors,52 membranes,53 sorbents in liquid−solid sorption processes,54 or supramolecular hosts for organometallic complexes55,56 and polyoxometalates.57 Due to the cavity’s unique hydrophobic character and inherent chirality of CDs, chiral recognition related to their host−guest chemistry has been widely investigated,44,55,58−60 and these macrocyclic molecules have also been widely used in various chromatography techniques, and this issue has been extensively reviewed.61−68 While the applications of nonfunctionalized CDs in the field of host−guest chemistry have been reported widely,8−10,13−18 their employment as molecular building blocks to fabricate multifunctional materials and devices remains an area much less explored.69 CDs can be linked both noncovalently and covalently. For instance, native CDs have appeared as suitable ring components in the construction of [2]-rotaxanes or polyrotaxanes (for an example, see Figure 2c)70−72 and 2D supramolecular framework through synergistic ionic selfassembly of cationic α-CD-based pseudorotaxane unit as bridging sticks and anionic PW11VO404− cluster as nodes in water (Figure 2d).73 Owing to their unique architectures and properties, CD-based rotaxanes have triggered a lot of research interest aimed at exploring their possible applications in the design of molecular machines, sensors, and drug delivery systems, and this chemistry has been nicely summarized in recent reviews.71,74,75 CDs can also be used to construct supramolecular photoresponsive materials by forming host− guest complexes with photoactive molecules like azoben-

Figure 3. Schematic illustration of the red-light-responsive drug delivery system constructed by mesoporous silica nanoparticles modified with mAzo/β-CD supramolecular valves. (Reprinted with permission from ref 82. Copyright 2016 American Chemical Society.)

demonstrated that doxorubicin could be released from the modified mesoporous silica nanoparticles under red-light irradiation in deep tissue. Native cyclodextrins in combination with azobenzenecontaining molecules have also been applied in the design of photoresponsive host−guest systems to generate hydrogels and supramolecular polymers or control catalysts activity.83−85 For example, Harada et al. reported that stimulus-responsive supramolecular materials are formed by mixing an aqueous solution of a host polymer containing CD molecules with that of a guest polymer containing azobenzene.86−88 The shaking of the photoresponsive guest gel in the presence of the host gel leads to gel adhesion through host−guest interactions, and the assembled gels separate into separate pure gels on irradiation with ultraviolet light (Figure 4a).89 In turn, Zhao et al. demonstrated that the catalytic process of an ester hydrolysis by a mononuclear zinc complex of a dimeric β-CD ligand can be switched on and off using UV−vis irradiation in the presence of azobenzene-functionalized Au NPs (Figure 4b).84 Under visible light, the azobenzene units are in trans position and bind tightly to the β-CD rings leading to inactive catalysis. After the transto-cis photoisomerization under UV irradiation, the azobenzene units released the β-CD rings and the catalyst becomes available for the ester hydrolysis. Supramolecular host−guest systems based on CDs have also led to the development of redoxresponsive and metal-ion-responsive actuators. For example, a gel containing β-CD and ferrocene as a guest molecule shows an expansion−contraction process in response to the oxidation and reduction of the ferrocene molecules (Figure 4c).90 In 13464


Chemical Reviews

Review

coordination flexibility of nonfunctionalized CDs to metal ions, as a result of deprotonation of the secondary hydroxyl groups, is described in section 3. In particular, we summarize the design strategies for the formation of molecular homo- or heterometallic sandwich-type complexes depending on the nature of metal ions used. It is also demonstrated that the reaction systems involving native CDs as site-directing ligands and magnetic metal ions can open up new opportunities in development of novel molecular magnetic materials. In section 4 we demonstrate that CDs can be treated as very attractive building units that can be interconnected by alkali-metal cations to form highly porous carbohydrate metal−organic frameworks (CD−MOFs). Members of this new class of highly porous materials can act as efficient host templates in the construction of nanomaterials with the desired functionality. Moreover, CDs as well-known “green” molecular hosts have also been widely used as ideal functional molecules to improve the solubility, stability, and bioavailability of inorganic nanoparticles. In section 5 the preparation methods of metal nanoparticle colloids stabilized by α-, β-, and γ-CDs and their potential applications in the field of catalysis and chemical sensing is described. Section 6 focuses on the preparation and application of water-soluble native CDs-modified semiconducting quantum dots (QDs), magnetic and other inorganic nanoparticles that have steadily emerged over the past decade.

2. INCLUSION COMPLEXES OF NATIVE CYCLODEXTRINS WITH ORGANOMETALLICS AND COORDINATION COMPOUNDS Native and modified cyclodextrins are interesting organic host systems that can form noncovalent host−guest inclusion complexes with a wide variety of organometallic molecules, which was nicely review by Monflier and co-workers.55 In these inclusion compounds CDs act as second-sphere coordination ligands, and the inclusion complexation of a CD with an organometallic guest is driven by several factors such as van der Waals forces, hydrophobic interactions, and electronic and steric effects. In addition, the inclusion generally modifies the chemical, electrochemical, and photochemical properties of guest compounds. In this subsection we discuss the second-sphere coordination chemistry of organometallics with nonfunctionalized CDs. The most thoroughly studied organometallic complexes that can form inclusion complexes with CDs are those bearing hydrophobic ligands such as cyclopentadienyl (Cp = η5C5H5) groups. The first examples of host−guest adducts between native CDs and ferrocene (Fc) were prepared by Harada and Takahashi in 1984.93 Since then the interactions of a broad variety of Fc derivatives with native94,95 as well as functionalized96−98 CDs have been reported. These works revealed that the stoichiometry of Fc-CD inclusion complexes was dependent on the cavity sizes of the CDs used. For example, the interaction of α-CD with Fc led to the formation of a crystalline 2:l inclusion complex in which the Fc molecule is encapsulated by two α-CDs in a tail-to-tail orientation as shown in Figure 5a.99 In other works, the interaction of α-CD with [Rh(η5-C5H5)2]PF6·2(α-CD)·8H2O100 or mixed sandwich complex [(η5-C5H5)Fe(η6-C6H6)](PF6)101 also resulted in the formation of 2:1 adducts. In turn, for both the Fc-β-CD and the Fc-γ-CDs inclusion complexes a 1:1 stoichiometry was suggested by NMR and mass spectroscopy measurements.102,103 Recently, a novel 4:5 stoichiometry inclusion complex between β-CD and Fc was prepared and structurally

Figure 4. Schematic illustrations of (a) photoresponsive, (b) photoswitchable catalysis (Reprinted with permission from ref 84. Copyright 2012 John Wiley & Sons.), (c) redox-responsive, and (d) metal-ion-responsive supramolecular actuators. (Reprinted with permission from ref 92.Copyright 2014 American Chemical Society.)

another example, a supramolecular adhesion of hybrid gels was achieved by addition of a metal ion.91 It was observed that the polymer hydrogel modified with both β-CD and 2,2′-bipyridyl (β-CD-bpy gel) does not adhere to the polyacrylamide gel (guest gel) in the absence of metal ions; however, both gels adhered after the β-CD-bpy gel was immersed in a MCl2 (M = Cu2+, Ni2+, Zn2+) aqueous solution (Figure 4d). These stimuliresponsive supramolecular materials have many potential applications, including remotely controlled materials and medical devices.92 In this review, we focus on the developments in the field of synthesis and structure characterization of various systems based on metal ion complexes and inorganic nanoparticles with unmodified cyclodextrins. We also survey emerging research areas based on these intriguing systems and identify possible future directions. Schematic representation of various native CD−metal systems and CD-modified inorganic nanoparticles is shown in Scheme 2. First, we provide the most prominent examples of α-, β-, and γ-CDs’ inclusion complexes with selected organometallics and coordination compounds as guests (section 2) by which we contribute an update on the research in this field since the previous review in 2006.55 The 13465


Chemical Reviews

Review

Scheme 2. Representation of Selected Native CD−Metal and CD−Inorganic Nanoparticle Systems

Figure 6. Molecular structure of cis-dioxovanadium(V) inclusion complexes: (a) K[VO 2 (salhybiph)@(β-CD) 2 ] and (b) K[VO2(salhybiph)@(α-CD)2]·18H2O.

Figure 5. Molecular structure of ferrocene adducts with (a) α-CD and (b) β-CD.

remaining polar part of the complex is situated outside the primary hydroxy side of the β-CD host. The similar reaction in the presence of α-CD led also to the formation of 1:2 inclusion compound K[VO2(salhybiph)@(α-CD)2]·18H2O albeit with a different architecture.105 The supramolecular structure of the inclusion compound is established through hydrogen-bonding interactions between adjacent β-CD molecules and the π−π stacking ability of the biphenyl side chain of the cisdioxovanadium(V) complexes (Figure 6b). Unmodified CDs are also known to bind efficiently organometallics incorporating η6-arene,107 η3-allyl,108,109 and diene ligand,110,111 and a few of these types of inclusion complexes were characterized using single-crystal X-ray crystallography (Figure 7); strikingly, similar host−guest complexes between CDs and η5-cyclopentadienyl metal (Fe,112 Mn,113 Cr,114 Mo115,116) complexes have eluded

characterized.104 In the molecular structure, four of the five Fc molecules are included in the cavities of four β-CDs along the axial orientation of the tetramer, while the fifth Fc molecule is equatorially coincluded by two β-CDs (Figure 5b). Other structural motifs of inclusion complexes based on native cyclodextrins and organometallics were observed upon encapsulation of a cis-dioxovanadium(V) complex incorporating an O,N,O-tridentate ligand with a terminal aromatic ring by α-CD or β-CD hosts.105,106 The reaction of KVO3 with the Nsalicylidene hydrazide (H2salhybiph) ligand in the presence of β-CD yielded the 1:2 inclusion compound K[VO2(salhybiph) @(β-CD)2] (Figure 6a).105 The molecular structure analysis revealed that the apolar biphenyl side chain of the ligand is located within the hydrophobic cavity of β-CDs, whereas the 13466


Chemical Reviews

Review

Scheme 3. Supramolecular Recyclable Catalyst for Aqueous Suzuki−Miyaura Coupling

Figure 7. Second-sphere inclusion complexes of the respective CD with (a) (η6-arene)·Cr(CO)3, (b) [{Pd(η6-C3H5)(μ-X)}2], and (c) Rh(cyclooctadiene)NH2(CH2)2NH2·PF6.

single-crystal X-ray analysis to date and been characterized using elemental analysis, FTIR and NMR spectroscopies, thermographic analysis (TGA), or powder X-ray. For example, a range of η6-arene chromium tricarbonyl complexes was shown to form crystalline 1:1 adducts with β-CD and γ-CDs (Figure 7a).107 Upon addition of β-CD or γ-CD to a dimeric complex [{Pd(η6-C3H5)(μ-X)}2] (where X = Cl, Br, or I) in aqueous solution 1:1 inclusion compounds are formed at 40 °C (Figure 7b).108 Under similar conditions a 1:1 adduct between α-CD and a Rh(cyclooctadiene)NH2(CH2)2NH2·PF6 complex was also obtained (Figure 7c).110 Analysis of the molecular structure revealed that the cyclooctadiene ligand adopts a boat conformation with one of the two ethylene units inserted into the α-CD cavity. A great variety of inclusion compounds of cyclodextrins with platinum-group metal complexes as guests have been synthesized117 and used in catalytic processes118−124 or bioactivity studies.125−129 In 1985 Stoddart and co-workers for the first time used cyclodextrins as encapsulatory vehicles for platinum(II) complexes.130,131 The authors demonstrated that cyclobutane-1,1-dicarboxylatodiammine−platinum(II) ([Pt(NH3)2(CBDCA)] forms a 1:1 adduct with α-CD in aqueous solution as well as in the solid state. The adduct is stabilized by N−H···O hydrogen-bonding interactions between the two NH3 ligands with the secondary hydroxyl groups on αCD as well as hydrophobic interactions resulting from penetration of the cyclobutane ring of the complex into the α-CD cavity. In analogous studies Harada and co-workers observed the formation of a 1:1 inclusion compound between α-CD and [PtX2-(cyclooctadiene))][PF6] (X = Cl, Br, I) complexes.118,119 In this case the cyclooctadiene ligand adopts a boat conformation, and one −CH2−CH2− subunit of this ligand penetrates into the cyclodextrin cavity. In recent years Pt(IV) complexes have emerged as promising prodrugs of biologically active Pt(II) complexes, and the first investigations on the interaction of Pt(IV) complexes, namely, cis,cis,trans[Pt(NH3)2Cl2L2] (where L = aromatic carboxylate of different chain length)126 and 1-adamantanemethylamine−Pt(IV) complex, were investigated.127 Supramolecular catalysis has recently emerged as a subdiscipline of catalysis directed to design catalytic systems using supramolecular approaches.132 In this regard there are a handful of examples of various inclusion compounds of native cyclodextrins, particularly with platinum-group metal complexes, which have been used as homogeneous aqueous-phase catalysts.118−122,124 In these catalytic systems CDs can stabilize metal-centered catalytic centers or modify the selectivity via through-space control. For example, a water-soluble, supramolecular catalytic system, based on an inclusion complex between a hydrophilic β-CD and a hydrophobic palladium(II)− dipyrazole complex bearing an adamantyl (Ad) molecular as a

recognition moiety, was designed and used for Suzuki−Miyaura coupling reaction (Scheme 3).122 Besides their well-known ability to transfer substrates from organic to aqueous phases, CDs appeared as an efficient host to thermoregulate the interfacial surface activity of an amphiphilic ligand at the aqueous/organic interface.121 A biphasic system containing βCD and 1-(4-tert-butyl)benzyl-1-azonia-3,5-diaza-7-phosphaadamantyl ligand was used in a Rh-catalyzed hydroformylation of olefins, and an increase in the catalytic activity was observed upon increasing the temperature from 80 to 100 °C (Scheme 4). In this way inclusion of the hydrophobic part of an amphiphilic phosphane into the hydrophobic cavity of a supramolecular receptor was thermocontrolled that in turn strongly influenced the catalytic activity. While all previous investigations on supramolecular catalysis have been conducted traditionally in solution, in 2017 Hapiot and co-workers reported on the Rh-catalyzed hydroformylation of alkenes to the corresponding aldehydes under CO/H2 pressure in the presence of CD additives in a planetary ball mill.124 This is the first example of CD-assisted selectivity control under solvent-free ball milling. These unprecedented results pave the way to further developments of catalytic processes with high catalytic activity and unusual selectivity in the solid state. Interestingly, Stoddart and co-workers revealed recently that cyclodextrins are also capable to form inclusion complexes with ionic metal salts by the example of second-sphere coordination chemistry of gold complexes.133,134 The authors demonstrated that various ionic metal salts such as MAuX4 (M = Na/K/Rb/ Cs, X = Cl/Br) form selectively CD-based host−guest inclusion complexes even in the presence of other square-planar palladium and platinum complexes.133 For example, the reaction between α-CD and KAuBr4 in aqueous solution led to the formation of a supramolecular complex with an extended {[K(OH2)6][AuBr4]@(α-CD)2}n chain superstructure after a 1 week crystallization process. Single-crystal X-ray analysis showed that the cavities of the α-CDs oriented head-to-head and tail-to-tail form a 1D channel, which is filled by [K(OH2)6]+ and [AuBr4]− ions in an alternating fashion through multiple preorganized hydrogen-bonding interactions (Figure 8). The authors suggested that the formation of such supramolecular structure arises as a consequence of the perfect structural correspondence between the stereoelectronics associated with [K(OH2)6]+, [AuBr4]−, and α-CD. Remarkably, this type of molecular recognition involving the second-sphere coordination chemistry of gold complexes and eco-friendly CDs was used for the green and economic recovery process of gold.134 13467


Chemical Reviews

Review

Scheme 4. Illustration of Thermocontrolled Catalysis Using β-CD and 1-(4-tert-Butyl)benzyl-1-azonia-3,5-diaza-7phosphaadamantyl Ligand

between two γ-CD tori, as exemplified for B12Br122− in Figure 9a. An analogous inclusion complex with α-CD and a dicyclohexasilicate ion was reported.137 In this case, the reaction of α-CD with tetramethoxysilane in aqueous potassium hydroxide solution led to formation of an inclusion complex in which dicyclohexasilicate ions (Si12O3012−) are included between two α-CD tori (Figure 9b). The charge on the silicate ion is compensated by potassium ions, which are coordinated by water molecules and a hexagonal face of a silicate prism. In another example Au15 quantum clusters were anchored in cyclodextrin (α-, β-, and γ-CDs) cavities via host−guest chemistry.138 The host−guest interaction was proved by circular dichroism and two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy. Recently, reactions of a mixture of polyoxometallate (POM) H3[PMo12O40], LaCl3· 7H2O, with γ-CD or β-CD in deionized H2O led to the

Figure 8. Supramolecular structure of {[K(OH2)6][AuBr4]@(αCD)2}n: (a) molecular building unit and (b) view of the onedimensional nanostructure extending along the c axis.

Besides a wide range of inclusion compounds between CDs with mononuclear metal complexes55,105 or a handful of ionic metal salts,133,134 there are also a few structurally wellcharacterized examples of the self-assembly of polynuclear inorganic clusters and native CDs. For example, dodecaborate anions of the type [B12X12]2− and [B12X11Y2−] (where X = H, Cl, Br, I and Y = OH, SH, NH3+, NR3+) were found to form strong 1:2 inclusion complexes with γ-CD by slow diffusion of methanol (over 3 days) into a saturated aqueous solutions of γCD and Na2B12Br12.135,136 Single-crystal X-ray diffraction analysis revealed that dodecaborate clusters are included Figure 10. Structure of CD−POM-1: (a) molecular building unit and (b) supramolecular structure of the CD−POM-1 showing the aligned one-dimensional tubular stacks of the complexes.

formation of two organic−inorganic hybrid 1:2 complexes, [La(H2O)9]{[PMo12O40]@[γ-CD]2} (CD−POM-1) (Figure 10) and [La(H2O)9]{[PMo12O40]@[β-CD]2} (CD−POM-2), respectively.57 Single-crystal X-ray analysis revealed that both complexes have a sandwich-like structure, where one [PMo12O40]3− is encapsulated by the primary faces of two CD tori through intermolecular hydrogen-bonding [C−H···O] and [C−H···OMo] interactions. The hydrated [La(H2O)9]3+ counter cations are found outside the CD channels and stabilized through electrostatic and hydrogen-bonding interactions. Additionally, a network of [O−H···O] hydrogenbonding interactions between the 2° faces of the CD tori

Figure 9. Entrapment of (a) the B12Br122− cluster into a γ-CD dimeric capsule and (b) Si12O3012− ion between two α-CD tori. 13468


Chemical Reviews

Review

through a set of weak attractive interactions including electrostatic, ion−dipole, and hydrogen bonding. In the same work, the authors also demonstrated that a cationic cluster [Ta6Br12(H2O)6]2+ exhibits a high tendency to form a 1:2 inclusion complex with γ-CD. The structural analysis revealed that the [Ta6Br12(H2O)6]2+ cluster is closely embedded into two γ-CDs involving their secondary face through multiple hydrogen bonds (Figure 11d). Interestingly, the ditopic supramolecular cation {[Ta6Br12(H2O)6]@2γ-CD}2+ and [P2W18O62]6− anion interact together to give a threecomponent 1D tubular polymeric chain resulting from periodic alternation of POMs and clusters (Figure 11e). The supramolecular complementarity between the CDs, the POMs, and the polynuclear inorganic clusters pave the way toward building new functional materials for catalysis, photocatalysis, and biomedical applications.

resulted in the formation of infinite 1D bamboo-like supramolecular structures, as exemplified for CD−POM-1 in Figure 10.

Figure 11. Structural representation of the supramolecular [P2W18O62]6−@γ-CD along their X-ray diffraction analysis showing the (a) 1:1, (b) 1:2, and (c) 1:3 arrangements. (d) Solid-state structure of the supramolecular host−guest {[Ta6Br12(H2O)6]@2γ-CD}2+ complex. (e) Structural representation of the 1D tubular chain showing periodic alternation of the ditopic cation {Ta6@2CD}2+ and the anionic [P2W18O62]6− running along the c axis. (Reprinted with permission from ref 139. Copyright 2017 American Chemical Society.)

3. METAL ION COMPLEXES WITH UNMODIFIED CYCLODEXTRINS Interactions of native cyclodextrins with metal ions have remained a largely undeveloped research area due to the difficulties with the isolation of well-defined systems and/or reliable characterization methods. Interest in CD−metal complexes largely stems from their potential applications in catalysis, molecular recognition, and sensing. However, the scarcity of structural data and mechanistic insights derived from the combination of in situ/operando spectroscopic measurements is one of the key obstacles precluding rational design of catalytic systems in aqueous and organic solutions or other potentially functional systems based on CD−metal complexes.

Very recently, Cadot and co-workers reported that other types of POM, i.e., namely, [P2W18O62]6− anion, interact with γ-CD forming aggregates with 1:1, 1:2, and 1:3 stoichiometry in the solid state depending on the alkali salts used (Figure 11a− c).139 In these supramolecular structures, the γ-CD moiety interacts with the Dawson-type anion through its primary face

Scheme 5. Showcase of Coordination Flexibility of Native CDs toward Metal Ions

13469


Chemical Reviews

Review

Scheme 6. Proposed Structural Motifs for Cu(II) Ion Complexes with Native CDs in Alkaline Solutions: (a) Cu2(OH)2-α-CD2−, (b) Cu2(OH)(O)-β-CD3−, (c) Cu(OH)2α-CD2−, (d) Cu2-β-CD, and (e) CuX2 Salts with CDs in Dichloromethane

the metal ions by a CD molecule. Structurally well-defined metal ion complexes with native CD in the solid state are discussed in section 3.2, and in this section we describe investigations on metal ion complexes with native CDs in solution. From the number of reported investigations only selected examples are presented, and more examples can be found in the review by Norkus.140 It should be noted that most of the data obtained are only qualitative and do not provide exhausted information on complicated equilibria and the stability of CD−metal complexes in solutions. Among various metal ion complexes with native CDs (Scheme 5b), CD−Cu(II) systems have been most thoroughly investigated. The first investigations on the complexation of Cu(II) ions with native CD in alkaline solutions were performed by Matsui and co-workers over four decades ago.147−149 The authors proposed the formation of dinuclear complexes formulated as shown in Scheme 6a and 6b on the basis of spectroscopic (FTIR, Raman), potentiometric, and conductometric studies. In the case of α-CD both metal ions are themselves linked to each either through two μ-OH bridges, whereas one μ-OH bridge and μ-O bridge was observed in the case of β-CD. Spectroscopic evidence for an interaction of the Cu(II) ions to the CD secondary hydroxyl groups in these binuclear hydroxy-bridged structures were also provided by others.150,151 Matsui and co-workers also reported the possible formation of 1:1 dihydroxy−Cu(II)−β-CD complex in alkaline solution (pH = 12) in which β-CD was in the form of doubledeprotonated anion (Scheme 6c).152 In turn, formation of solely dinuclear Cu2-β-CD complex without hydroxy bridges was observed in alkaline aqueous medium (pH = 12.5) under conditions of metal ion excess (Scheme 6d).153 More recently, Rossi and co-workers proposed a simple procedure to characterize the physicochemical properties of CD−CuX2-type complexes derived from reactions between α-, β-, and γ-CDs and CuX2 salts (where X = Br, Cl, and NO3 anions) in dichloromethane as an organic solvent.154 In addition, general trends in thermal stability, spectroscopic properties, and inclusion in the cavity were analyzed. On the basis of these procedures, the authors proposed formation of complexes with 1:1 stoichiometry exhibiting various structural motifs with an octahedral or distorted octahedral geometry (Scheme 6e). Interactions of other divalent metal ions with unmodified cyclodextrins have been studied to a lesser extent. For example, CDs with magnesium and calcium salt hydrates tend to form

Early works focused on the analysis of interactions of native and modified CDs with metal ions in alkalaine solution. The stability and composition of CD-based metal complexes was mainly characterized by voltammetric and UV-spectrophotometric methods; these studies are summarized in a review by Norkus.140 However, the successful determination of the molecular structure of both modified16 and native141 CDbased metal complexes remains a challenging task, and the relatively limited structural data stems in part from difficulties to obtain a good quality crystalline material. The used main group and transition-metal ions are important structural components in forming strong, highly directional metal−CD bonds. This availability of reactive sites, in combination with a plethora of metal ions, contributes to the diversity of the products obtained. The deprotonation and complexation of secondary hydroxyl groups of CDs to metal ions usually leads to the formation of sandwich-type complexes where partly or fully deprotonated CD molecules are connected through a multinuclear homometallic or heterometallic metallomacrocycle ring (Scheme 5a). In this section we describe the coordination flexibility of nonfunctionalized CDs toward metal ions in solution and put a special emphasis on the solid-state molecular and supramolecular structures. The emerging applications of CD−metal complexes in the field of gas storage, catalysis, sensing, and molecular magnetic materials have also been summarized. 3.1. Studies on the Composition of Native CD−Metal Complexes in Solution

Metal ion complexes with unmodified cyclodextrins continue to generate sustained interest due to their potential applications in domains as different as environmental science142,143 or catalysis among others (vide infra). However, structural characterization of metal complexes with native CDs in solution is a challenging issue, and the coordination chemistry of these reaction systems remains far from being exhausted. In aqueous solution, a CD molecule exists in the form of a hydrate as well as metal salts may exist in the form of a neutral hydrate or ionic species. CDs have a number of primary and secondary hydroxyl groups that can provide plenty of coordination sites to chelate metal ions and form covalent bonds at basic pH, where the OH groups can be deprotonated and act as nucleophiles.144 In addition, water is a highly competitive medium for both transition-metal complexation and molecular recognition.145,146 CDs in solutions dramatically enhance the solubility of metal salts to form various complexes based on first-sphere coordination of 13470


Chemical Reviews

Review

Figure 12. SEM images and DLS plots of β-CD/Fe nanospheres prepared by adding acetone to a solution at speeds of 20, 0.2, and 0.025 mL/s, respectively. (Reprinted with permission from ref 161. Copyright 2010 American Chemical Society.)

whereas the Fe(OAc)2 solution without β-CD showed iron precipitation after 1 day. Moreover, 1H NMR investigation of the interaction between β-CD and iron(II) acetate showed that the peaks corresponding to β-CD were broadened and their spin−spin splitting disappeared. These findings were attributed to the presence of Fe2+ ions surrounded with β-CD molecules in solution. After addition of acetone to the solution of β-CD and Fe(OAc)2, the β-CD nanospheres were generated by formation of iron-embedded β-CD primary particles with disordered cage-type structure. The presence of well-dispersed Fe2+ ions in the β-CD nanospheres was confirmed by inductively coupled plasma atomic emission spectroscopy and high-resolution transmission electron microscopy. Interestingly, the size of the β-CD nanospheres was adjusted by changing the speed with which the acetone was added, and the particle size decreases with increasing acetone addition speed (Figure 12).

inclusion complexes incorporating the hydrated metal cation (vide infra, section 3.2.1). In turn, the interaction between βCD and Pb(II) ions was studied in alkaline solution using polarographic and UV-spectrophotometric investigations, and formation of a neutral complex with 1:1 stoichiometry was observed at pH 10−11.5.155 Some works on interactions of CDs with metal ions in a trivalent oxidation state have also been reported (Mn, Fe, or La). Thermodynamic and structural studies of inclusion complexes between trivalent lanthanide ions and native cyclodextrins demonstrated that a hydrated La(III) ion forms a 1:1 adduct with α-CD under acidic aqueous solution (pH = 2−4);156 detailed NMR studies reveals that the metal ion is coordinated to anomeric O atoms of α-CD in the vicinity of the C5 carbon atom. In turn, a dinuclear bis(μhydroxo)-bridged structure was proposed for a complex incorporating Mn(III) cations in the partly deprotonated βCD cavity157 and a tetranuclear hydroxy-bridged structural motif for a Fe4-β-CD complex (based on solution-phase magnetic susceptibility studies).158 Klüfers and co-workers investigated spectroscopically a series of CDs complexes with tetravalent ions [Sn(IV), Pb(IV), Mn(IV), Ge(IV), V(IV), Si(IV)] in alkaline solution. For example, the 119Sn NMR spectrum of a 3-fold molar amount of β-CD with hexahydroxidostannate(IV) indicated the presence of hexacoordinate, tin-containing species in solution at pH higher than 11, and the data were consistent with the respective single-crystal X-ray analysis (vide infra).159 Recently, the interaction between pentavalent vanadium VO32− ions and βCD was investigated in aqueous solutions (pH = 7.5).160 The multinuclear (1H, 13C, 51V) NMR spectroscopy coupled with measurements of diffusion coefficients and electrical conductivity supported the formation of 2:1 (β-CD/vanadium) complex. A new impact to investigations on interactions of metal ions with CDs in solution provides a recent report on self-assembly of β-CD into size-controllable nanospheres in the presence of Fe2+ ions.161 The authors found that the as-prepared β-CD/ Fe(OAc)2 system was stable in DMF solution up to 1 week,

3.2. Structurally Well-Defined Native CD−Metal Complexes

3.2.1. Homometallic Complexes. The chemistry of homometallic CD−metal complexes is still in its infancy and a challenge for experimental chemists. In neutral aqueous solutions CDs form relatively low-stability complexes with metal centers. Strikingly, to date, there is only one report on the structurally crystalline form from a saturated water solution of β-CD and CuCl2. Single-crystal X-ray well characterized a complex consisting of a transition-metal salt and a neutral CD without any side arm support, namely, a β-CD/CuCl 2 complex.162 The β-CD/CuCl2 was isolated in diffraction analysis and was revealed to have two levels of organization in its crystal structure, leading to a 1D supramolecular polymeric structure (Figure 13). A hydrated CuCl2 molecule is coordinated by the secondary OH group of one CD molecule and simultaneously forms an inclusion complex with the second CD molecule. In the presence of metal ions CDs may crystallize in the form of inclusion complexes or molecular complexes incorporating the metal cations. The ability of metal ion hydrates to form supramolecular complexes with CDs is nicely demonstrated by the isolation and single-crystal X-ray crystallo13471


Chemical Reviews

Review

cationic centers through four O atoms forming an airscrew-like structure. Remarkably, there are only two examples of the isolated and structurally characterized homometallic sandwich-type complexes (type II, Scheme 3). The multinuclear complexes were obtained in a reaction between Pb2+ and β-CD or γ-CD in aqueous solution.166,167 In 1994, Klüfers and co-workers reported on the synthesis and structural characterization of a homometallic hexadecanuclear sandwich-type complex with formula [Pb16(γ-CD)2]·20H2O.166 The molecular structure of this unique complex comprises two partly deprotonated γ-CD molecules connected through a hexadeca-membered ring (Figure 15). Each glycosidic oxygen atom is coordinated to two bridging Pb2+ cations, while the primary alcohols remain protonated. The similar cluster with a {Pb14} metallamacrocycle was isolated from a biphasic solvothermal reaction of PbCl2 and β-CD in a water/cyclohexanol mixture.167 Analysis of the crystal structure of homometallic sandwich-type complex [Pb16(γ-CD)2]·20H2O revealed that noncovalent interactions lead to the formation of a nonporous supramolecular architecture (Figure 15c). In contrast, the self-assembly processes of heterometallic sandwich-type complexes can lead to the formation of 2D layers with open 1D channels, see section 3.3. 3.2.2. Heterometallic Complexes. Structurally wellcharacterized heterometallic CD−metal complexes are more common in comparison to their homometallic analogues and exhibit a rich variety of molecular and supramolecular structures. Remarkably, all known well-defined metal ions complexes of this type with unmodified CDs are based on a combination of an alkali-metal ion and a transition-metal center. Reactions of transition-metal salts with native CDs in the presence of auxiliary alkali-metal ions (Li+, Na+, K+, or Rb+) lead to the formation of a family of heterometallic sandwichtype complexes (types III−V, Scheme 3). In these systems, metal ions distribution in the metallomacrocycle ring can appear in different patterns depending on the inherent number of coordination sites in a CD molecule and the character of auxiliary ions used. For example, Klüfers and co-workers reported on the synthesis of heterometallic α-CD sandwichtype complex of formula Li3[(α-CD)2Cu3Li3(H2O)3]·41H2O containing a six-membered heterometallic ring in which three Cu2+ and three Li+ cations are grouped in three {Cu, Li} units and capped by two partly deprotonated α-CD molecules (Figure 16a and 16b).168 A similar {Cu, Li}n alternate metal ion distribution in the metallomacrocycle ring was observed in the sandwich-type complex obtained in the reaction of γ-CD with Cu(NO3)2·2.5H2O and LiOH in aqueous solution.169 Interestingly, the reaction of α-CD with FeCl2 and LiOH resulted in formation of a sandwich-type complex with formula Li5[Li6(H2O)6Fe3(H2O)3(α-CD)2]·56H2O consisting of a nonamembered heterometallic ring in which three Fe2+ and six Li+ ions are grouped in three {Fe, Li, Li} units (Figure 16c and 16d).170 A similar molecular structure was also observed with Mn2+ ions.170 Recently, heterometallic dodecanuclear sandwich-type complex with formula [(γ-CD)2Co4Li8(H2O)12]171 (vide infra, Figure 21a) were isolated and structurally characterized. In this case the molecular structure is based on two eight times deprotonated γ-CD molecules connected through a dodecamembered heterometallic ring in which four Co2+ and eight Li+ ions are grouped in four {Co, Li, Li} units.

Figure 13. Supramolecular structure of a β-CD−CuCl2 complex: (a) View of the one-dimensional nanostructure extending along the c axis and (b) side and (c) top view of the inclusion complex between CuCl2 with the one CD molecule.

graphic characterization of a supramolecular complex involving β-CD and a hydrated [Mg(H2O)6]2+ ion163 or α-CD and a hydrated calcium chloride salt.164 For example, the crystal structure of α-CD@CaCl2·19H2O is comprised of an α-CD molecule bridging two types of octacoordinated Ca2+ ions, and each α-CD is connected to another six Ca2+ ions by a secondary hydroxy group, forming a supramolecular structure with 1D open channels along the b axes.164 For mono- and dinuclear metal ion complexes with partly deprotonated unmodified CDs, a bucket-wheel-shaped assembly has also seldom been reported. The first examples of this type of complexes were only reported by Klüfers and coworkers in 2006.159 The authors synthesized and structurally characterized a series of mononuclear β-CD complexes of the formula [M4+(β-CD)3] (where M = Sn, Pb, Ge, Mn). These molecular complexes contain one six-coordinate metal center, three β-CD dianions, and three tetrahedral tetraaqualithium cations that assemble into a bucket-wheel-shaped architecture with 3-fold rotational symmetry (type I, Scheme 3). Another type of a bucket-wheel complex of the formula [Sn2(β-CD)3]· H2O was synthesized and structurally characterized by Su and co-workers (Figure 14).165 In the molecular structure of [Sn2(β-CD)3]·H2O each β-CD anion coordinates to two Sn4+

Figure 14. Molecular structure of [Sn2(β-CD)3]·H2O: (a) top view and (b) side view. (Reprinted with permission from ref 141. Copyright 2016 Elsevier.) 13472


Chemical Reviews

Review

Figure 15. Molecular structure of [Pb16(γ-CD)2]·20H2O: (a) side view and (b) top view. Supramolecular structure view along (c) the a axis and (d) the c axis. (Reprinted with permission from ref 141. Copyright 2016 Elsevier.)

Figure 16. (a) Molecular structure of Li3[(α-CD)2Cu3Li3(H2O)3]·41H2O: side and top view. (b) Schematic representation of the H-bond system in Li3[(α-CD)2Cu3Li3(H2O)3]·41H2O. (c) Molecular structure of Li5[Li6(H2O)6Fe3(H2O)3(α-CD)2]·56H2O: side and top view. (d) Schematic representation of the H-bond system in Li5[Li6(H2O)6Fe3(H2O)3(α-CD)2]·56H2O. (Reprinted with permission from ref 141. Copyright 2016 Elsevier.)

CD)2]·59H2O (Figure 17).170 In the case of K+ and Rb+ auxiliary ions, due to their larger size, such ions are located outside the cavity of sandwich-type complexes and link the adjacent molecules into more extended structures (type V, Scheme 3). By combining α-CD with Cu2+ in the presence of KOH or RbOH, the dark blue crystals of dinuclear sandwichtype cuprate complexes with formula K4[Cu2(α-CD)]·23H2O·

Each Co2+and Li+ center adopts a distorted trigonal bipyramidal geometry. Utilization of Na+ as an auxiliary ion promotes the formation of {M, Na}n metallomacrocycle (type IV, Scheme 3). For example, experiments involving α-CD with VO2+ in the presence of Na+ as auxiliary ion resulted in formation of a sandwich-type complex with formula Na6[Na6(H2O)6(VO)6(α13473


Chemical Reviews

Review

Figure 17. (a) Molecular structure of Na6[Na6(H2O)6(VO)6(α-CD)2]·59H2O: side view. (b) Schematic representation of the metallamacrocycle, and (c) H-bond system in Na6[Na6(H2O)6(VO)6(α-CD)2]·59H2O. (Reprinted with permission from ref 141. Copyright 2016 Elsevier.)

Figure 18. (a) Molecular structure of K4[Cu2(α-CD)]·23H2O·2acetone and Rb4[Cu2(α-CD)]·21H2O·2acetone: side view. (b) Schematic representation of the metallomacrocycle and H-bond system in K4[Cu2(α-CD)]·23H2O·2acetone and Rb4[Cu2(α-CD)]·21H2O·2acetone. (Reprinted with permission from ref 141. Copyright 2016 Elsevier.)

Scheme 7. Representation of the Observed Supramolecular Assemblies of CD−Metal Complexes: (a−c) Sandwich-Type Complexes and (d) Mononuclear Bucket Wheel Complexes

3.3. Supramolecular Architectures of CD−Metal Complexes

2acetone and Rb4[Cu2(α-CD)]·21H2O·2acetone were formed after diffusion of acetone vapor within a few days (Figure 18a and 18b).168 The metallomacrocycle of such compounds consists of two Cu2+ ions, whereas K+ or Rb+ ions are located outside the cavity of sandwich-type complexes and link the adjacent molecules in a 3D tetragonal rod-packing array.

The self-assembly of molecular entities through noncovalentinteraction-driven self-assembly processes represents a very attractive way to create a large variety of ordered functional structures.172 A variety of noncovalent porous materials (NPMs) derived from discrete organic molecules,173 molecular 13474


Chemical Reviews

Review

Figure 19. Supramolecular structure of selected sandwich-type complexes: (a) Li4[Li4(H2O)4Cu4(γ-CD)2], (b) [(γ-CD)2Co4Li8(H2O)12], (c) [Na6(H2O)6(Bi)6(α-CD)2]·47H2O, and (d) Na6[Na6(H2O)6(VO)6(α-CD)2]·59H2O.

metal complexes,174,175 and multinuclear metallamacrocycles176 with permanent porosity have been reported. This family of porous molecular assemblies opens the way to guest-responsive materials that can compete with classical metal−organic frameworks (MOFs) as highly selective adsorbents exhibiting enantioselective and gas sorption properties. Analysis of the crystal structures of CD−metal-based complexes revealed that noncovalent interactions can lead to the formation of supramolecular networks ranging from nonporous close-packed structures to more extended layered networks.141 In general, the self-assembly processes of CDbased sandwich-type complexes lead to the formation of pillarlike supramolecular networks containing 1D channels filled by solvent molecules. For example, in the crystal structure of

Li5[Li6(H2O)6Fe3(H2O)3(α-CD)2]·56H2O, adjacent molecules extend infinitely forming pillar-like structures stabilized by water-mediated H bonds, which results in the formation of 1D open channels filled by water molecules. These 1D columns are further organized by hydrogen bonds into tight 2D layers (Scheme 7a). A similar supramolecular motif was observed in K4[Cu2(α-CD)]·23H2O·2acetone. However, in the crystal structure of this complex the neighboring columns are twisted by a corresponding angle from each other, as illustrated in Scheme 7b. In turn, in the crystal structure of sandwich-type cuprate complex with formula [Na4Cu4(γ-CDH−3)4(H2O)] the adjacent molecules are arranged in a brickwork pattern to form a layer-type structure in which the adjacent layers are shifted to each other by one-half a CD molecule (Scheme 7c). Another 13475


Chemical Reviews

Review

pling reaction is based on the formation of a bimetallic aryl copper intermediate through the attack of the hydroxide ligand

type of supramolecular arrangement was observed in mononuclear β-CD complexes of the type [M4+(β-CD)3] (where M = Sn, Pb, Ge, Mn). In these crystal structures, the adjacent molecular moieties of [M4+(β-CD)3] are interconnected by hydrogen-bond interactions into an extended honeycomb 2D network (Scheme 7d). Supramolecular assemblies of CD-based sandwich-type complexes are very interesting in the context of further utilization of the cylindrical channels in adsorption of small guest molecules after removal of solvent molecules. Figure 18 depicts the view of pillar-like supramolecular networks containing 1D channels for selected sandwich-type complexes. Regrettably, the data concerning utilization of the resulted open porous networks for adsorption of gases or liquids is essentially lacking, likely due to the destruction of the overall network during thermal activation. Stoddart and co-workers reported on the gas adsorption properties of a sandwich-type complex Li4[Li4(H2O)4Cu4(γ-CD)2] self-assembling with formation of a regular tetragonal rod packing 2D supramolecular structure by water-mediated H bonds with 1D open channels (Figure 19a).169 Attempts to study the N2 adsorption isotherm at 77 K revealed no significant uptake up to 1 bar, thus indicating the presence of closely packed cylinders in the host framework which block diffusion of N2 molecules across the channel network at this low temperature. However, the porosity of the assemblies was accessible for CO2 at 273 K after removal of the solvent molecules. The observed uptake of CO2 was attributed to the thermal motion at higher temperatures and a higher affinity between the CD−metal-based assembly and the CO2 molecules. A similar pillared 2D supramolecular structure was observed in a sandwich-type complex of formula [(γCD)2Co4Li8(H2O)12].171 However, in this crystal structure the neighboring columns are translated by 7.22 Å and twisted by an angle of 35° (Figure 19b). This arrangement improved the intermolecular separation of Co2+ ions that exhibits fieldinduced slow magnetic relaxation (see section 3.5). Other interesting porous supramolecular motifs were observed for sandwich-type complexes of formulas [Na6(H2O)6(Bi)6(αCD)2]·47H2O and Na6[Na6(H2O)6(VO)6(α-CD)2]·59H2O. Noncovalent-interaction-driven self-assembly processes of the former complex led to the formation of a honeycomb 2D network (Figure 19c), while the adjacent molecules of the latter complex are organized by hydrogen-bond interactions into tight 2D layers (Figure 19d). Undoubtedly, further work needs to be addressed to drive advances in the utilization of unmodified CD-based metal complexes as gas adsorbers by applying different methods of activation. Moreover, one can expect progress in employment of CD-based metal complexes as chiral catalysts for asymmetric synthesis or chiral receptors for enantioselective separation of small chiral guests in the same vein as it has been observed for other type of metallomacrocycles;176,177 however, these issues still await exploration.

Scheme 8. Speculations on the Mechanism of Cu(II)2−βCD-Catalyzed Homocoupling of Arylboronic Acids

to the oxophilic boron center, which undergoes subsequent reductive elimination to the symmetrical biaryl compound (Scheme 8). The transformation was conducted under an aerobic atmosphere without the need of additional ligand or base. Moreover, the same catalyst Cu(II)2−β-CD complex exhibited high catalytic activity for the heterocoupling of amines with arylboronic acids (with high C−N coupling selectivity) and the synthesis of 1,2,3-triazoles through the click cyclization reaction of an arylboronic acid with an alkyne in the presence of sodium azide178 as well as for the air oxidation of arylboronic acids to phenols.180 Recently, the Pd(II)-β-CD complex was studied for the synthesis of unsymmetrical biaryls via Suzuki−Miyaura coupling reaction of aryl boronic acids with aryl halides in water.183 The CD-based metal complex systems have been also studied and applied as chiral selector184 and chemical sensors.185−187 For example, the dinuclear Cu(II)2−β-CD complex appeared as an efficient chiral selector to separate enantiomers of aromatic α-hydroxycarboxylic acids by chiral high-speed counter-current chromatography (HSCCC). The enantioseparation ability of Cu(II)2−β-CD complex increased in comparison to native βCD, mainly due to the ion-pairing interactions between deprotonation of the carboxyl group of α-hydroxycarboxylic acid and the Cu(II) ion of Cu(II)2−β-CD. In turn, [Pb14(βCD)2]·35H2O complex was used in sensing as a fluorescent probe for selective turn-on detection of H2S in living cells.185 The sensing mechanism is based on the coordination of H2S to a Pb(II) ion that significantly increases the fluorescence emission. In addition, this material can be easily utilized for fabricating visual H2S test papers exhibiting good selectivity and sensitivity to H2S sources (Figure 20a).186 Another work demonstrated that [Pb14(β-CD)2]·35H2O complex shows reducing capacity toward AuCl4− forming Au@Pb-β-CD NPs exhibiting excellent electrochemiluminescent (ECL) behavior, which is beneficial to fabricate an immunosensor for insulin (Figure 20b).187 The mechanism for detection of insulin is based on the energy transfer from Au@Pb-β-CD NPs (ECL donor) to chitosan/Ru(bpy)32+/silica NPs (CRuSi, ECL acceptor). First, the Au@Pb-β-CD NPs were deposited onto an electrode surface to immobilize primary antibody (Ab1) through Au-adsorbing proteins forming a sensing interface to insulin antigen. Next, the fabricated immunosensor was coated with insulin antigen solution and CRuSi NPs secondary antibody (Ab2-CRuSi NPs) solution providing a remarkable ECL response for quantitative detection of insulin.

3.4. Unmodified CD−Metal Complexes in Catalysis and Sensing

Metal complexes based on native CDs have been investigated as a nanoreactor catalyst in a variety of organic reactions. The combination of Cu(II) ions and hydrophilic CDs opens a new opportunity for water-soluble and very active catalysts.178−182 For example, as-synthesized dinuclear Cu(II)2−β-CD complex was utilized for the coupling reactions of arylboronic acids to produce symmetrical biaryls.178 The mechanism of homocou13476


Chemical Reviews

Review

Figure 20. (a) Illustration of the preparation and H2S detection of test papers based on [Pb14(β-CD)2]·35H2O complex. (Reprinted with permission from ref 186. Copyright 2017 Royal Chemistry Society.) (b) Schematic description of the fabrication process of the immunosensor. (Reprinted with permission from ref 187. Copyright 2016 American Chemical Society.)

Figure 21. Utilization of native CDs for the design of molecular magnetic materials by organizing magnetic ions into supramolecular architectures: case of (a) Na7[(VO)7Na7(H2O)7(β-CD)2] and (b) [(γ-CD)2Co4Li8(H2O)12].

3.5. Molecular Magnetic Materials as an Emerging Application of CD−Metal Complexes

leading to an antiferromagnetic ordering within the sevenmembered ring (Figure 21a). The authors noted that the heptagons of vanadium ions have two nearly degenerate S = 1/ 2 spin ground states, and the energy gaps depend upon ring distortions. More recently, Lewiński and co-workers developed a strategy for synthesis of the first single-ion magnet (SIM) based on CDs in which magnetic ions with suitable local magnetic anisotropy were effectively separated from each other. 171 In the cobalt−lithium−γ-CD complex [(γCD)2Co4Li8(H2O)12], γ-CD was used to template magnetic Co 2+ and nonmagnetic auxiliary Li + ions to form a heterometallic {Co, Li, Li}4 ring with ultimately increased magnetic ion Co···Co separation (Figure 21b). The individual Co2+ ions are prevented from superexchange magnetic coupling and exhibit a field-induced slow magnetic relaxation consistent with the SIM behavior. As such, this complex represents a grid of four Co2+-based SIMs replicated in a supramolecular architecture. These two pioneering examples demonstrate that CD−metal complexes offer unique opportunities in construction of novel magnetic materials, and more breakthroughs in this area should be expected in the near future.

Single-ion magnets (SIMs) are potential building blocks of novel quantum computing devices.188 Unique magnetic properties of SIMs require effective separation of magnetic ions and can be tuned by even slight changes in their coordination sphere geometry. The reaction systems involving native CDs as site-directing ligands and magnetic metal ions open up new opportunities in development of novel molecular magnetic materials. In 1991, the first studies on the solutionphase magnetic susceptibility studies were reported for a Fe(III)−β-CD complex formulated as [(Fe(III)(OH))4(βCD]·3H2O.189 The data shows room-temperature magnetic moments well below the spin-only values, indicating the presence of magnetic coupling between the metal ion centers, which gives rise to an antiferromagnetic character. Almost two decades later, Oshio and co-workers demonstrated for the first time a structurally well-defined sandwich-type oxovanadium(IV)−β-CD complex, Na 7[(VO)7Na7 (H2O)7(β-CD) 2]· 65H2O, which was explored as a potential single-molecule magnet.190 In the core structure, the magnetic oxo−vanadate ions are separated by single Na+ ions and grouped in seven alternating {V, Na} units with relatively short V···V distances 13477


Chemical Reviews

Review

Figure 22. (a) Stick representation of a single cubic (γ-CD)6 unit of γ-CD−MOF-1. (b) Space-filling representation of the (γ-CD)6 unit in which the six γ-CD rings forming the sides of the cube are shown in different colors. (c) Space-filling representation of the extended solid-state structure of γCD−MOF-1. (d) Configurational representation of the structure of the maltosyl repeating unit in γ-CD in γ-CD−MOF-1. (e and f) Representation of the different voids within the rra net topology in γ-CD−MOF-1. (Reprinted with permission from ref 201. Copyright 2010 John Wiley & Sons.)

4. CD-BASED METAL−ORGANIC FRAMEWORKS Metal−organic frameworks (MOFs) are a novel family of chemically diverse porous materials which for two decades have continued to fascinate the scientific community across many subdisciplines of chemistry and materials science due to their intrinsic aesthetic appeal and ubiquitous potential applications.191−197 MOFs are typically assembled from metal ions or inorganic clusters and organic multifunctional ligands through metal−ligand coordination bonds to afford periodic networks containing channels and cavities with controllable size.198 The structure and functionality of MOFs is strongly determined by both the inorganic and the organic components as they can directly incorporate their own functionalities in the metal− organic frameworks. In this regard, attempting to harness organic ligand libraries to enhance the versatility of MOFs with desirable attributes is a particularly challenging issue. Among the various types of organic ligands used for the formation of metal−organic networks,191,194,199,200 the application of classical inclusion molecules such as cyclodextrins as building units remains still in its infancy. In the following sections, the utility of native CDs in combination with alkali-metal salts for the construction of nanoporous metal−carbohydrate frameworks (namely, CD−MOFs), an area that is only really beginning to be studied in any great detail, and potential applications of CD−MOFs in various fields of materials science and nanotechnology have been highlighted.

(γ-CD)6 repeating motifs by coordination to the secondary faces of adjacent γ-CD tori through their C-2 and C-3 OH groups, resulting in a 3D network with interconnected voids. A large spherical pore of 1.7 nm diameter resides at the center of the cube and is connected by six pore windows (0.78 nm) defined by the γ-CD tori that adopts the faces of the cube. Further triangular channels (0.4 nm) are observed by orienting the structure 45° to each of the crystallographic axes. These channels represent the snubbed “corners” of the (γ-CD)6 units and are again prolonged infinitely in three dimensions (Figure 22e and 22f). Other isostructural CD−MOFs containing Rb+ and Cs+ ions, (γ-CD−MOF-2 and γ-CD−MOF-3, respectively), have also been synthesized and characterized.201 While attempts to crystallize γ-CD with Li+ alone resulted in nonporous material, a methodology that relies on the cocrystallization of LiOH and KOH with γ-CD was accomplished to produce partially Li+ ion-substituted CD− MOF-1 (Li/K-CD−MOF-1) without sacrificing the porous architecture.203 The frameworks of γ-CD−MOF-1 and Li/KCD−MOF-1 remain intact upon removal of the solvent guest molecules. The N2 adsorption measurements indicated the microporosities of these materials, and the BET surface areas for γ-CD−MOF-1 and Li/K-CD−MOF-1 are estimated to be 1145 and 1205 m2 g−1, respectively. More recently, by using amino-functionalized γ-CD and RbOH, a new metal−organic framework NH2−γ-CD−MOF-2 that is isostructural with pristine CD−MOF was isolated.204 Interestingly, CD−MOF may form polymorphic architectures. For example, during the crystallization process of γ-CD− MOF-3 the authors also observed the formation of another crystalline form with a different morphology.202 The new polymorph form defined as γ-CD−MOF-4 consists of γ-CD tori linked to one another through Cs+ ions coordination in primary face to secondary face fashion, forming a 1D channeltype structure (Figure 23a). In addition, Cs+ ions link these stacks of metal-linked γ-CD channels in a 3D network resembling a checkerboard-like arrangement. Each of the Cs+ ions is seven coordinate and bonded to four γ-CD tori through two glycosidic oxygen atoms and two primary and three

4.1. Structural Diversity of CD−MOFs

For the first time, CD−MOFs were synthesized and structurally characterized by Stoddart and co-workers.201,202 γ-CD−MOF-1 was prepared by combining γ-CD with KOH in aqueous solution at room temperature.201 The crystal structure of γCD−MOF-1 comprises infinite body-centered frameworks of (γ-CD)6 cubic units linked by four alkali-metal cations (Figure 22). The γ-CD units adopt the faces of a cube, with their primary faces pointing toward the cube interior and linked to one another by the coordination of four K+ ions to the primary C-6 OH groups and the glycosidic ring oxygen atoms (Figure 22d). Each K+ ion is also involved in the assembly of pairs of 13478


Chemical Reviews

Review

by large cavities inside the crystal structure with maximum and minimum diameters of 6.8 and 3.2 Å, respectively. While γ-CD is a chiral building block, no superstructures with induced chirality have been reported so far. In turn, it was demonstrated that the α-CD/RbOH system can form an extended porous superstructure in which the CD metal− carbohydrate framework displays left-handed helical channels.205 Single-crystal XRD analysis revealed that the helical

Figure 23. (a) Crystal packing of γ-CD−MOF-4 viewed down the crystallographic c axis. (b) Side-on view showing the primary face to secondary face orientation of the γ-CD rings in the extended structure. (c) Top view of the arrangement of Cs+ ions around two γ-CD units. (d) Coordination sphere of the Cs+ ions. (Reprinted with permission from ref 202. Copyright 2012 American Chemical Society.)

secondary hydroxyl groups (Figure 23d). The packing arrangement of γ-CD−MOF-4 revealed the presence of two different channel types, one which is defined by the inner cavities (0.78 nm in diameter) of the γ-CD tori forming stacks and another defined by the interstitial spaces (0.7 nm) between the γ-CD channels. The framework of γ-CD−MOF-4 is stable to the activation process, and a modest surface area of 339 m2 g−1 has been calculated by the BET method, based on the N2 adsorption isotherm measured at 77 K. Another interesting example of CD−MOFs was derived from a divalent alkaline earth metal in the presence of γ-CD. In the reaction of SrBr2 with γ-CD in aqueous solution, followed by diffusion of methanol, a compound with the formula [(SrBr2)(γ-CD)]n was isolated.202 In the crystal structure, each of the nine-coordinate Sr2+ ions is linked to three individual γ-CD tori (via six Sr−O bonds) and three molecules of water. Each γ-CD tori is coordinated to three Sr2+ ions, forming a 3D trigonal framework exhibiting convoluted and nonlinear channel structure (Figure 24a−c). The channel structure is punctuated

Figure 25. Ball and stick representation of the topology of the 3D helical framework β-CD−MOF-1 from different orientations. (Reprinted with permission from ref 206. Copyright 2015 Elsevier.)

superstructure is created by the coordination of Rb+ ions to the primary and secondary faces of the α-CD tori. The chirality of the α-CD tori induces this supramolecular helicity in the CD metal−carbohydrate framework in the solid state. Recently, by using β-CD and a sodium salt, a new metal−organic framework β-CD−MOF-1 with chiral helical structure was isolated.206 The crystal structure of β-CD−MOF-1 exhibits a 3D framework with left-handed helical channels running through the structure created by the ligation of Na+ ions to the primary and secondary faces of the β-CDs rings (Figure 25). In turn, the reaction of β-CD with NaOH or KOH resulted in the formation of two new isostructural carbohydrate metal−organic frameworks, Na−-β-CD−MOF and K−β-CD−MOF.207 In the case of Na−β-CD−MOF, two adjacent β-CDs are connected

Figure 24. (a) Crystal packing of [(SrBr2)(γ-CD)]n viewed down the c axis. (b) Channels (red) running down the crystallographic c axis, visualized by calculating the solvent-accessible pore space for a spherical molecule of radius 1 Å, bound within a parallelepiped corresponding to a supercell of 2 2 2 unit cells. (c) Calculated voids (blue) accessible to a spherical molecule of 1.85 Å radius, which corresponds well to the size of the N2 molecule. (d−f) Coordination environment of Sr2+ ions in the solid-state structure of [(SrBr2)(γ-CD)]n. (Reprinted with permission from ref 202. Copyright 2012 American Chemical Society.) 13479


Chemical Reviews

Review

interactions resulted in the formation of a 2D framework with open channels constituting 19.5% potential guest-accessible volume of the crystal volume based on the PLATON calculation (Figure 27b). When the applied template agent was ibuprofen the reaction resulted in the formation of Cs− CD−MOF-2 exhibiting different channel arrays of the CD molecules. The asymmetric unit of Cs−CD−MOF-2 consists of the 10-coordinated Cs+ ion linked to three pairs of β-CD molecules, and each pair stacks in a primary face to primary face/secondary face to secondary face (PTP/STS) manner (Figure 27c). Each β-CD molecule is connected to seven Cs+ ions by donating its secondary hydroxyl, primary hydroxyl, and glycosidic ring oxygen atom of α-1,4-linked glucopyranosyl forming a 3D framework with 1D channels (Figure 27d). Another strategy that can provide a robust coordination supramolecular network containing CDs is to strengthen the coordination bond between the CDs and the metal ions by using functionalized CDs. For example, 2D cyclodextrin−metal coordination polymer was formed by connecting paddle-wheel Cu2+ units through a γ-CD functionalized with eight carboxylate groups.209 In the crystal structure each functionalized γ-CD ligand is coordinated to eight Cu2+ ions through eight sulfurylpropionate arms, resulting in the formation of 2fold-interpenetrated layers running along the ab plane (Figure 28). On the basis of PLATON calculations, the potential guestaccessible volume of the crystal volume is estimated to constitute 41.1% of the unit cell volume; however, this free volume is filled with highly disordered water molecules. It is worthy of note that the biggest drawback of CD−MOF materials is their decomposition/dissolution upon exposure to water, although this issue can be mitigated somewhat through postsynthetic modification of the parent framework. For example, to improve the stability of γ-CD−MOF-1 nanoparticles in an aqueous environment, a facile procedure for the incorporation of poly(acrylic acid) ,210 hydrophobic C60,211 and cholesterol212 in their matrices was recently presented. Sada and co-workers described a bottom-up approach to the synthesis of nano- and microsized cubic gel particles with well-defined shapes and sizes from CD−MOFs that can act as potential drug carriers and cell-support materials.213 The authors accomplished preparation of cubic gel particle by the transformation of γ-CD−MOF-1 to gel particle via internal cross-linking of γ-CD by bifunctional epoxide (Figure 29). The original cubic shape of the γ-CD−MOF-1 was retained after removal of coordinated metal ions. The development of synthetic procedures for extended metal−carbohydrate frameworks and their suitable arrangements in nanoporous networks have pushed these novel framework systems into new and advanced applications that have not been considered before. The following section provides an overview of the use of CD−MOFs in nanotechnology as smart materials in energy storage, environmental protection, and biological relevant fields.

Figure 26. Ball and stick representation of the “T”-shaped structure with (a) bowl-like pore and (b) “8”-type double channels. (Reprinted with permission from ref 207. Copyright 2015 Elsevier.)

by Na ions leading to the formation of the “T”-shaped structure with a bowl-like pore (Figure 26a). These “T”-shaped structures stacked along the b axis form the “8”-type double channels (Figure 26b). Additionally, each of the double-channel

Figure 27. (a) View of the 1D chain constructed by the alternating arrangement of Cs+ ions along the b direction. (b) Crystal packing structure of Cs-CD−MOF-1. (c) View of three pairs of β-CD molecules linked to a 10-coordinated Cs+ ion; each pair stacks in a primary face to primary face/secondary face to secondary face (PTP/ STS) manner. (d) Crystal packing structure of Cs-CD−MOF-1. (Reprinted with permission from ref 208. Copyright 2017 Royal Chemistry Society.)

units are held together via interactions between Na+ and Oalkoxide atoms, leading to formation of 2D layers in the ab planes. Very recently, the reaction of β-CD with CsCl in the presence of selective template agents resulted in the formation of two helical Cs−CD−MOFs.208 The addition of 1,2,3triazole-4,5-dicarboxylic acid to the reaction mixture provides Cs−CD−MOF-1 in which the six-coordinated Cs+ ion is shared by three neighboring β-CD molecules, forming a 1D chain, as shown in Figure 27a. Additionally, a network of Cs−O

4.2. Advanced Functional Materials Based on CD−MOFs

The combination of CDs with alkali-metal ions can pave the way toward many classes of novel and useful environmentally benign materials and devices showing promising application potentials in the field of separation, sensing, and drug delivery systems. These emerging studies are discussed in this subsection, and the examples described are categorized according to their function. 13480


Chemical Reviews

Review

Figure 28. (a) View showing that each functionalized CD (red) is connected to four other linkers (pink, blue, orange, and green) through four paddle-wheel Cu2+ units. (b and c) Space-filling and stick representation of the 2-fold interpenetrated layer along the ⟨11̅0⟩ direction. (Reprinted with permission from ref 209. Copyright 2016 American Chemical Society.)

Figure 29. Synthesis of cubic gel particles. (a) Crystallization. (b) Cross-linking reaction. (c) Removal of coordinated metal ions. Reprinted with permission from ref 213. Copyright 2012 John Wiley & Sons.

4.2.1. Small Molecules Adsorption and Separation. The inclusion properties of CDs offer interesting properties for CD-based MOFs. CD−MOFs, owing to their open robust frameworks, are considered as candidates for adsorption and separation of gases, vapors, or liquids. For example, γ-CD− MOF-2 can be regarded as a promising material for carbon fixation due to the high affinity for CO2 over CH4, which is adsorbed in a reversible manner as a result of both the chemisorption and the physisorption processes.214 This selectivity was attributed to the free hydroxyl groups present in γ-CD−MOF-2 and the rapid reactivity of CO2 to form alkyl carbonic acids within the framework. The formation of an acidic product was monitored by solid-state 13C NMR spectroscopy and colorimetrically by swapping anions with a pH indicator (methyl red) within the nanoporous framework. The value added by using low-cost substrates and the ability to absorb CO2 from the atmosphere makes this material an attractive device for sensing carbon dioxide.215 MOFs are known to facilitate energy-efficient separations of important industrial chemical feedstocks. In this regard, CD− MOFs have also shown high shape selectivity toward aromatic hydrocarbons.216 A retention order of o-xylene > m-xylene > pxylene was indicated by adsorption isotherms and liquid-phase chromatographic measurements. The persistence of the revealed regioselectivity was also observed during the liquidphase chromatography of the ethyltoluene and cymene regioisomers. Moreover, molecular shape sorting within CD− MOFs facilitated separation of the industrially relevant mixture (benzene, toluene, ethylbenzene, and xylene isomers). More recently, the ability of CD−MOFs to act as a separation medium for a wide variety of organic compounds, including alkyl-, vinyl-, and haloaromatics, saturated, and unsaturated alicyclic as well as chiral compounds, was demonstrated.217 Undoubtedly, these findings open the way to cheap and easyto-prepare stationary-phase materials for HPLC separations. 4.2.2. Molecular Recognition and Sensing. CD−MOF materials have the capacity to recognize small molecules, showing promising application potential in the field of

Figure 30. Reversible and responsive micropattern of methyl orange printed into γ-CD−MOF-2 changes from yellow to red when exposed to gaseous hydrochloric acid and back from red to yellow when exposed to ammonia gas. (Reprinted with permission from ref 218. Copyright 2011 John Wiley & Sons.)

chromatographic separation and sensing. For example, it was demonstrated that the inner cavity of γ-CD−MOF-2 is large enough to accommodate Rhodamine B and 4-phenylazophenol through the host−guest interactions.201 Furthermore, the robust crystallinity and porosity of γ-CD−MOF-2 offers an opportunity to prepare potential sensors.218 A series of micropatterns of pH- and photoresponsive dyes and indicators has been imprinted into crystals of γ-CD−MOF-2 by employing a MeOH-compatible agarose gel stamp. For example, a pH indicator pattern was prepared (e.g., methyl orange) for detecting the presence of ammonia or hydrochloric acid (Figure 30). The response for the acid/base sensing and the photochromic detection can be cycled a number of times without any noticeable decrease in the quality of the pattern or color intensity. These experiments open the way for developing potential MOF-based sensors for selective sorption of small toxic gas molecules or to pattern MOFs with metallic patterns for use in surface-enhanced Raman spectroscopy. Very recently, γ-CD−MOF-1 was utilized as a chiral stationary phase for separation of chiral aromatic alcohols.219 The γ-CD−MOF-1-packed column gave good resolution for 13481


Chemical Reviews

Review

which the MOF catalyzes electrochemical reactions on the nanoparticle surface. Grzybowski and co-workers also demonstrated that CD− MOFs can be utilized as host templates to metal nanoclusters.223 By carrying out the reaction of γ-CD, RbOH with a [Ru(bpy)3]Cl2 photocatalyst yellow-brown cocrystals of [Ru(bpy)3]Cl2/γ-CD−MOF-2 were obtained (Figure 33a). The amount of [Ru(bpy)3]Cl2 occluded in the CD−MOF cavities increased with the solution concentration of [Ru(bpy)3]Cl2. Due to the strong confinement by the CD−MOF matrix, [Ru(bpy)3]Cl2 was stable upon prolonged irradiation. The resulting photocatalytic system photoreduced various metal salts to the corresponding nanoparticles. For example, the immersion of hybrid crystals [Ru(bpy)3]Cl2/CD−MOF-2 in a solution of Pd(NO3)2 followed by washing in water released monodisperse Pd nanotriangles of 6−7 nm size as judged from high-resolution transmission electron microscopy (HRTEM) observations (Figure 33b). 4.2.4. Memory Devices. Owing to their insulating properties, most MOFs have not essentially been used as electronic materials for information processing. For the first time, Grzybowski and co-workers demonstrated that the metal/ MOF/metal heterostructure in which mobile ions are occluded into the MOF cavities appears as an excellent platform for nonvolatile resistive random access memory elements.224 Single crystals of γ-CD−MOF-2 were used as a material supporting electron transport that infused with an ionic electrolyte and flanked by silver electrodes acted as memristor (Figure 34). The prepared metal/γ-CD−MOF-2/metal heterostructure system exhibited a range of electrical properties that are useful for the construction of a nonvolatile memory device that can be repeatedly read, erased, and rewritten. The authors stated that the major limitation of the presented proof-of-the concept system is that the read/write times are slow (seconds) compared to commonly used memristors (nanoseconds to milliseconds). However, these times can be improved by improving the kinetics for oxidation/reduction and reducing the total amount of material needed to block current transport. 4.2.5. CD−MOFs-Based Drug Delivery Systems. MOFs have attracted a great deal of attention for biomedical uses as carriers for therapeutic agents.225,226 In this regard, the potential of porous γ-CD−MOF-1 as a drug carrier has been also explored theoretically and experimentally. For example, grand canonical Monte Carlo (GCMC) simulations demonstrated that the adsorption isotherm for ibuprofen in γ-CD− MOF-1 exhibits two well-defined steps in which the molecules are first adsorbed in the narrow cylindrical channels of 8 Å diameter, followed by saturation of the main cavities of 1.7 nm in diameter.227 The controlled release process involving γ-CD− MOF-1 can be inferred on account of its high energy of

Figure 31. Application of CD−MOF for the separation of chiral aromatic alcohols. (Reprinted with permission from ref 219. Copyright 2017 Royal Chemistry Society.)

the separation of chiral aromatic alcohols such as (R,S)-1phenyl-1-propanol, (R,S)-1- phenyl-1-butanol, and (R,S)-2phenyl-1-butanol (Figure 31). These results demonstrate the potential application of CD−MOFs in high-performance liquid chromatography (HPLC). 4.2.3. CD−MOFs as Host Template to Metal and Metal Oxide Nanoclusters or Nanoparticles. Recently, there has been growing interest in using various porous MOF materials as host templates with incorporated metal and metal oxide nanoclusters or nanoparticles (NPs).220 The utility of CD− MOFs for the incorporation of metal NPs was demonstrated by Grzybowski and co-workers.221 The authors developed a strategy for the incorporation of Au NPs into γ-CD−MOFs cavities based on an autoredox reaction. The immersion process of γ-CD−MOF-2 or γ-CD−MOF-3 crystals in a solution of AgNO3 and HAuCl4 led to the formation of corresponding metal NPs. In this procedure the OH− counterions included in the frameworks either alone or cooperatively with the CD units reduce the metal salt precursors to their respective NPs (Figure 32). Moreover, the amount of deposited metal NPs was controlled by the immersion time of CD−MOFs in the metal ion solution and the concentration of the metal salts. Whereas Ag NPs were deposited throughout the entire CD−MOFs, Au NPs were located predominantly in the core of the crystal and surrounded by a clear NP-free peripheral region. Moreover, the combination of the deposition modes of Ag and Au allowed for the synthesis of core/shell CD−MOFs. In the first step, immersion of CD−MOFs crystals in a HAuCl4 solution formed a core of Au NPs (>90%), which was washed with acetonitrile and then immersed in a AgNO3 solution to deposit Ag NPs (>90%) in the shell region. Further investigations revealed that the Ag@γ-CD−MOF-2 system exhibits a dark conductivity of ∼2 × 10−11 S cm−1, which increases by about 4 orders of magnitude upon light irradiation.222 MOFs are typically poor electrical conductors, and the discussed example represents the first general strategy for achieving electrically conductive MOF by adding metal nanocrystals to the MOF interior. The authors stated that this concept should provide new composite materials, i.e., electrocatalysts and photoelectrocatalysts, in

Figure 32. Diffusion and reduction of Ag+ ions within CD−MOFs as well as the release of the Ag NPs upon dissolution of the MOF in water. (Reprinted with permission from ref 221. Copyright 2012 John Wiley & Sons.) 13482


Chemical Reviews

Review

Figure 33. (a) Illustration of the physical incorporation of [Ru(bpy)3]Cl2 into CD−MOF matrix by cocrystallization. (b) TEM and HRTEM images of produced Pd nanotriangles. (Reprinted with permission from ref 223. Copyright 2013 John Wiley & Sons.)

simulations.210,228 However, γ-CD−MOF-1 can be easily dissolved in an aqueous environment that hampers its practical application. Nevertheless, variously modified γ-CD−MOF-1 materials with improved stability in an aqueous environment were successfully exploited as a drug delivery vehicle for ibuprofen (Figure 35)210 and anticancer drug doxorubicin211 with a loading capacity of 12 and 6.5 wt %, respectively. The composite microspheres not only exhibit spherical shapes and sustained drug release over a prolonged period of time but also demonstrate reduced cell toxicity. In other works, β-CD− MOF-1 as well as Cs-CD−MOFs were demonstrated as efficient carriers for inclusion and loading the drug molecules of 5-FU (5-fluorouracil).207,208

5. NATIVE CYCLODEXTRINS AS STABILIZERS FOR METAL NANOPARTICLE COLLOIDS Metal NPs have attracted a growing interest of researchers due to their wide spectrum of potential applications in fields such as catalysis,229,230 sensing, or nanomedicine.231,232 The utility of NPs for any particular application strongly depends upon their physicochemical properties. Thus, a variety of synthetic strategies have been adopted to synthesize metal NPs with size, shape, and composition control. For application in biological sensing or in cell imaging the corresponding nanoparticles must be soluble in water, and much attention has been paid to the development of green synthetic approaches leading to aqueous suspensions of nanoparticles. In this context, CDs have appeared to be very eco-friendly capping agents for the metal nanoparticles synthesis. The role of CDs is diverse, ranging from stabilization of the NPs by providing a protective layer that prevents aggregation to increasing solubility in aqueous media. Functionalized CDs, especially thiolated CDs, have been widely employed to modify metal nanoparticle by interacting with proper guest molecules.233,234 However, there have only been a handful of reports on the use of native CDs to induce NPs assembly via host− guest interactions due to their relatively weak capping ability for metal NPs. In the following sections we focus on the preparation methods of metal NP colloids stabilized by α-, β-, and γ-CDs and briefly describe the reported applications of such systems in the field of catalysis and chemical sensing.

Figure 34. Schematic representation of a memory device based on a CD−MOF. (a) MOF memory device comprising two silver electrodes and Rb-CD−MOF crystal containing hydroxy and rubidium ions and water. (b) Photograph of a ca. 1 mm cubic Rb-CD−MOF crystal (in a red rectangle) placed on a flash memory stick. (c) Cyclic voltammetry analysis of a silver/CD−MOF/silver device heterostructure. (Reprinted with permission from ref 224. Copyright 2014 John Wiley & Sons.)

5.1. Synthetic Methods of Metal Nanoparticles Stabilized by Native CDs

Figure 35. Illustration of burst and sustained drug release mechanism from γ-CD−MOF-1 nanocrystals and γ-CD−MOF-1/poly(acrylic acid) matrix, respectively. (Reprinted with permission from ref 210. Copyright 2017 American Chemical Society.)

In this subsection we describe advances in the field of native CD-stabilized metal nanoparticle (NP) that have steadily emerged over the last three decades. The examples described are categorized according to the research approach applied. Modification of the metal NPs surface by native CDs is a useful tool for their stabilization, size and shape control, prevention toward agglomeration, as well as increasing compatibility with

adsorption. The loading capacity of ibuprofen within the porous framework of CD−MOF-1 was confirmed experimentally and proves to be very close to that predicted by 13483


Chemical Reviews

Review

demonstrated the preparation of Au NPs by reduction of HAuCl4 with either sodium citrate or sodium borohydride in the presence of native CDs (Figure 36a).236 The results showed that the particle size of Au NPs was dependent upon the type and concentration of CD used. A significant improvement in size reduction and stability of gold colloids nanoparticle was achieved by the laser-induced ablation of a solid gold plate in aqueous β-CD at different pH values (Figure 36b).237 In particular, the experiments performed at pH below 5 resulted in fast agglomeration of the gold colloids, whereas those performed at high pH values (pH 6 and 9) led to the formation of stable NPs with an average diameter of 2.5 nm. Very recently, CD-capped Au NPs were achieved by reduction of the respective metal salt under microwave irradiation (600 W, 30 s)238 or ball-milling conditions.239 The latter work is the first example of the formation of Au NPs using CDs as reductive agents under ball-milling conditions. The catalytic properties of the resulting saccharide-stabilized Au NPs toward the reduction of nitrobenzene derivatives under ball-milling conditions were investigated. The catalytic performance depends upon the type of cyclodextrin, the nature and location of the substituent on the benzene, and the ball-milling frequency conditions. Native CDs were also successfully utilized for the controlled synthesis of silver nanostructures in aqueous solutions. Fan and co-workers synthesized sub-10 nm water-soluble Ag NPs by reduction of silver nitrate with sodium borohydride in the presence of α-CDs.240 Stabilization of the Ag NPs was achieved by hydrophobic interactions with the apolar primary faces of αCDs. Interestingly, head-to-head hydrogen-bonding interactions between the exposed secondary −OH groups facilitate the threading of the neighboring CDs to drive the self-assembly of the Ag NPs into 1-D arrays. Further studies revealed that native CDs showed mark differences in their efficiency to stabilize Ag nanoparticle colloids, and γ-CD exhibited a more efficient effect in stabilizing the Ag colloids than α- or β-CDs.241

Figure 36. (a) Synthesis of Au NPs by reduction of hydrogen tetrachloroaurate(III) in the presence of β-CD and a reducing agent. (b) Synthesis of Au NPs by the laser-induced ablation of a solid gold plate in the presence of β-CD. (c) Synthesis of Pt NPs via light irradiation of a host−guest inclusion complex between β-CD and platinum acetylacetonate. (d) Synthesis of FePt NPs. (e) Synthesis of bimetallic Au@Ag core−shell NPs. (f) Synthetic procedure for the formation of Au nanodendrites.

water environment or introducing additional functionalities. The first example of native CD-stabilized metal NPs was reported by Komiyana in 1983.235 In this case, the refluxing of an aqueous solution of Rh(III) and α-CD or β-CD in the presence of ethanol led to the formation of a colloidal suspension of CD-capped Rh NPs. Most studies on the synthesis of metal NPs by using CDs as templating agents were usually conducted in the presence of reducing agents and/or external energies. For example, Luong and co-workers

Figure 37. Structural and spectroscopic characterization of the Au NPs coated by (a−d) α-CD, (e−h) β-CD, and (i−l) γ-CD. (Reprinted with permission from ref 245. Copyright 2016 American Chemical Society.) 13484


Chemical Reviews

Review

Figure 38. Schematic illustration of the 1D/2D self-assembly of β-CD@Au NPs modulated by TCPP concentration.

Ag and Pd in aqueous solution.249 In this case, Ag seeds were prepared by reduction of silver nitrate with sodium borohydride in the presence of sodium citrate dihydrate as a stabilizer. In the next step, seeds were added to a “growth” solution containing the same Ag precursor, β-CD, and ascorbic acid (AA) acting as a weak reducing agent. It was demonstrated that β-CD influenced the final morphology of Ag NPs through a strong capping effect. In particular, increasing the β-CD/Ag molar ratio led to the selective formation of twinned icosahedral Ag NPs. However, the interactions of β-CD with palladium led to the controlled aggregation of Pd NPs into nanodendrites or multipods depending on the β-CD concentration. The observed different behavior of β-CD with Pd compared to Ag appears to result from a different interaction affinity of β-CD with these two metals. The shape and morphology of CDcoated metallic nanocrystals has been also controlled by using surfactants or polymers playing an important role during the formation process of nanocrystals with various structures. A few reports on the shape-controlled synthesis of Au nanostructures with the assistance of supramolecular complexes of surfactants with β-CDs have been published.250,251 For example, the planar Au nanodendrites with a symmetric single-crystalline structure consisting of trunks and side branches were obtained by reducing chloroauric acid with ascorbic acid (AA) in aqueous mixed solutions of dodecyltrimethylammonium bromide (DTAB) and β-CD.251 The formation of inclusion complexes of DTAB with β-CD due to host−guest interaction was essential for the fabrication of such Au nanodendrites (Figure 36f). Recently, poly(N-vinylcaprolactam) (PVCL) microgels modified with α-CDs were used to reduce and stabilize Au NPs.252 The presence of α-CD in the microgels allows a homogeneous distribution of Au NPs in colloidal polymer without adding any reducing agents and surfactants. The β-CD@Au NPs system was also regarded as a promising building block for the construction of well-defined supramolecular architectures by simple modulation of the mediator tetrakis(4-carboxyphenyl)porphyrin (TCCP) concentration.245 TCCP ligand contains four carboxylate groups that provide multiple possibilities of the host−guest interactions with β-CD. For example, a 1D chain-like self-assembled architecture was obtained by addition of 0.1 μM TCPP into a β-CD@Au NPs solution. In turn, as the mediator concentration was enhanced to 0.3 μM the β-CD@Au NPs assembled into a 2D supramolecular network (Figure 38).

Unmodified CDs, owing to their special hydrophobic cavities, have been also employed in the facile one-step synthesis of metal NPs through the decomposition of metal clusters included in their interior, initiated by external stimuli. For example, the platinum NPs with an average diameter of 2 nm were easily obtained through visible light irradiation of a host−guest inclusion complex between β-CD and platinum acetylacetonate (Pt(acac)2) in a water solution (Figure 36c).242 In a similar manner, β-CDs acted as microcavities able to include the 2,4-pentandionato of silver(I) complex Ag(acac).243 The synthesis of Ag NPs with an average size of about 5 nm occurred spontaneously in aqueous medium through thermal intramolecular electron transfer from the coordinated molecules to the metal center with the reduction of the Ag+ ion to metallic silver and consequently release of the free protonated ligand. In turn, the addition of Fe(CO)5 to the reaction system involving (Pt(acac)2), γ-CD, and oleic acid resulted in the formation of FePt NPs with a Fe-rich core and Pt-rich shell and an average diameter of 2.5 nm (Figure 36d).244 The authors demonstrated that the CD-modified FePt NPs exhibit superparamagnetic behavior at 300 K with zero remanence and coercivity. Further work in the synthesis of metal NPs revealed that CD molecules can act as both capping and reducing agent in alkaline medium.245−248 By simply heating the mixture of native CD molecules, chloroauric acid, and phosphate buffer solution (PBS, pH 7.0) to 100 °C the spherical and monodisperse Au NPs 15−20 nm in diameter was obtained, as determined by SEM, TEM, and dynamic light scattering (DLS) (Figure 37).245 Further detailed FT-IR and X-ray photoelectron spectroscopy (XPS) studies allowed us to investigate the surface chemistry between CD and Au NPs. During the reduction of metal salts, the primary alcohol group of the CD was oxidized into a carboxylic acid, providing a negative surface charge on the metal−particle surface and thus acting as stabilizer. In another work, Pal and co-workers reported on the weak reducing capability of the β-CD molecule in alkaline solution at room temperature that led to the formation of Au and Ag as well as bimetallic Au@Ag core−shell NPs (Figure 36e).246 The preparation of shape-controlled metallic NPs has attracted much attention due to their importance in understanding the fractal growth phenomena and their potential applications in catalysis. A variety of Ag nanostructures varying from spherical or polygonal to rod-, flower-, wire-, and ant-like Ag nanostructures were obtained by simple alteration of the reaction conditions.247 Recently, a seed-mediated approach was developed to the synthesis of shape-controlled nanostructured 13485


Chemical Reviews

Review

genated under 40 bar of H2 with TOF values up to 350 h−1, a higher value than observed in a CD-based Ru NPs catalytic system without using hydrogel.260 Moreover, the catalyst can be efficiently recycled and reused for the next catalytic cycles. In other work, the combination of α-CD with poly(N-vinylcaprolactam) (PVCL) microgel has been applied to reduce and stabilize Au NPs which displayed valuable performance for the selective reduction of aromatic nitro compounds.252 Due to the ability of α-CD to form inclusion complexes with specific compounds, the synthesized hybrid system PVCL−α-CD−Au showed different catalytic activity depending on the character of the aromatic nitro compounds used. Thus, the significant enhancement in the catalytic activity of the PVCL−α-CD−Au system was observed for the reduction of 4-nitrophenol, while no obvious effect was found for the reduction of 2,6-dimethyl4-nitrophenol (Figure 39). Similarly, the Ag NPs were immobilized in the network of poly(N-isopropylacrylamide) (PNIPAAm) hydrogel and α-CD to catalyze the reduction of 4nitrophenol to 4-aminophenol.261

5.2. Applications of Metal Nanoparticles Stabilized by Native CDs

5.2.1. Catalysis. Catalysis mediated by metal-based NPs is nowadays undergoing explosive development in the exploration of synthetic methods and the diversity of reactions.253,254 The efficiency of colloidal metallic particles in catalysis is closely related to their stability in the course of the reaction, and the choice of capping agent is critical as it controls the size, shape, and dispersion of the particles as well as should provide longterm stability during the catalytic process. CDs proved to be attractive molecules to efficiently stabilize catalytically active nanospecies in aqueous media. The application of metal NP colloids stabilized by native and functionalized CDs appears to be a very appealing strategy for the mass transfer in aqueous− organic two-phase systems and the development of catalytic processes in water. Various catalytic reactions such as arenes hydrogenations, olefins reduction, or cross-coupling reactions were successfully achieved with good yields and selectivities according to the relevant choice of CD-capped metal NPs.27−30,255,256 While considerable progress has been made in the development of efficient functionalized CD-capped metal NPs over the last three decades, the development of related systems based on native CDs has been relatively insubstantial. The first example of a catalytic system based on metal NPs stabilized by a native CD was reported in 1983.235 A colloidal suspension of rhodium particles was prepared by refluxing of an aqueous solution of rhodium(III) and α-CD or β-CD in the presence of ethanol and applied as a novel catalyst for the hydrogenation of olefins. Native CDs have also attracted a wide amount interest in the synthesis and stabilization of other transition-metal NPs employed for organic catalytic reactions in water. For example, the systems consisting of β-CD-capped Pd NPs were utilized as active catalysts for C−C bond formation.257,258 The investigation of this catalyst system in the Suzuki−Miyaura cross-coupling reaction of bromobenzene with phenylboronic acid gave exclusively biphenyl in 95% yield after 2 h (Scheme 9).258 In other works, the β-CD/Pd NPs were found to be very active in the hydrogenation of cinnamaldehyde,249 while the γ-CD/FePt NPs were successfully employed for the hydrogenation of allyl alcohol and the reduction of p-nitrophenol.244 The efficiency of such nanocatalyst was attributed to CDs that act not only as the protective ligands preventing particle agglomeration but also as the artificial host for organic substrates in aqueous media.

Figure 39. Immobilization and reduction of 4-nitrophenol on the αCD-modified Au NP.252

Another interesting aspect of catalytic applications of CDsupported metal NPs is enzyme-mimicking activity. Recent work demonstrated that the β-CD@Au NPs can exhibit mimicking properties of both glucose oxidase and horseradish peroxidase simultaneously.245 This system was also active in the cascade reaction in which glucose was first catalytically oxidized with generation of gluconic acid and H2O2, and then the enzymatic H2O2 and preadded TMB (3,3′,5,5′-tetramethylbenzidine) were further catalyzed into H2O and oxTMB, respectively. The authors stated that the observed unprecedented catalytic properties of the β-CD@Au NPs derive from the unique topological structures of CD molecules and the resulting electron transfer effect from the Au NP surface to the appended CD molecules, as evidenced by experiments and density functional theory calculations. 5.2.2. Sensing. Modification of Ag and Au NP surfaces with native CDs can pave the way toward novel biological tracers as well as optoelectronic nanodevices. In particular, such systems were demonstrated as very effective substrates for the detection of various organic compounds using surface-enhanced Raman spectroscopy (SERS). The SERS technique is a very effective tool to analyze molecules by highly increasing the Raman signal intensity coming from molecules, which have been adsorbed on nanosized metallic surfaces.262 It was demonstrated in numerous papers that native CD-capped Au and Ag NPs exhibit a significant SERS effect to selected molecular probes

Scheme 9. Coupling Reaction of Bromobenzene with Phenylboronic Acid

The catalyst performance of CD-based metal NPs can be also improved by using additives such as supramolecular hydrogels that effectively control the growth of nanoparticles and increase catalytic activities and selectivities.37 For example, the efficient hydrogenation of alkenes can be observed by using Ru NPs catalyst embedded into a supramolecular CD-based hydrogel matrix containing a mixture of the N-alkylpyridinium amphiphile [py-N-(CH2)12OC6H3-3,5-(OMe)2]+(Br−) and αCD.259 The terminal and internal alkenes have been hydro13486


Chemical Reviews

Review

stability, and bioavailability of various semiconductor nanocrystals. Combination of the molecular recognition properties of CDs and the fluorescence properties of QDs has provided highly selective and sensitive sensing platforms for various targets. While the use of functionalized CDs for the synthesis of water-soluble QDs is quite advanced,274−276 the application of natural CDs as surface-coating agents for the formation of CDcoated QDs is essentially undeveloped area. For the first time, native CDs-modified CdSe/ZnS QDs were prepared by the sonochemical method.277 In this case, the phase transfer of TOPO-coated CdSe/ZnS QDs was conducted by ultrasonic irradiation of a mixture of the parent QDs and α-, β-, or γ-CD in anhydrous ethanol. This method based on the formation of a host−guest inclusion complex between the passivated TOPO ligand and CD by hydrophobic−hydrophobic interactions resulted in the higher stability of QDs in the hydrophilic medium. Further work revealed that such native CD-coated QDs allow for highly sensitive determination of phenol isomers by quenching fluorescence intensity (Figure 41). The quenching luminescence of the CD-coated QDs was attributed to the fact that the phenol molecules entered the cavity of the coating CD and competed with the passivated TOPO to form an inclusion complex. Thus, CDs were used as surface-coating agents of QDs and acted as acceptors toward p-nitrophenol and 1-naphthol that provided a rapid detection system for analysis of phenol isomers. Specifically, it was found that all of the phenols quenched the luminescence of QDs based on α-CD and β-CD but had very little effect on γ-CD QDs. In another work, Vancso and co-workers TOPO-coated CdSe/ZnS QDs successfully modified by ferrocenyl thiol ligands through the ligand exchange reaction.278 The resulting ferrocene-coated QDs underwent reversible phase transfer from organic solvent into water upon formation of inclusion complexes of β-CD with the ferrocene units on the surface of

(e.g., 1,10-phenanthroline, dopamine, aminopyrene, crystal violet, rhodamine B (RB), 4-aminothiophenol).250,251,263 Then, for example, a (RB−β-CD@Au NP) composite can be employed as an energy acceptor for turn-on fluorescent sensing of cholesterol based on the guest replacement reaction as shown in Figure 40.245 In addition, β-CD-stabilized Au NPs revealed a unique ability to detect micromolar quantities of Pb2+ in the presence of other interfering metal cations, resulting in a visual color change from red to blue.238

Figure 40. Schematic illustration of fluorescent turn-on detection of cholesterol using the (RB−β-CD@Au NP) composite.

6. PREPARATION AND APPLICATION OF NATIVE CYCLODEXTRINS-MODIFIED SEMICONDUCTOR AND MAGNETIC NANOPARTICLES 6.1. Semiconductor Nanocrystals Coated by Native CDs

Semiconductor nanocrystals (NCs) exhibit unique optical and photophysical properties, and the synthesis and characterization of quantum-sized nanocrystals, i.e., commonly termed as quantum dots (QDs), represent one of the major advances in materials science in the last two decades.264−267 Due to their superior optical and electronic properties QDs have been widely used as fluorescence probes in biology, medicine, and analytical chemistry.268−271 For luminescence applications, QDs offer some advantages compared with conventional chromophores, such as broad absorption, narrow emission lines, low photobleaching, long lifetimes, and high quantum yields. For application of QDs in biological sensing or in cell imaging the corresponding nanoparticles must be dispersible in aqueous solution and in relevant biological buffers. This problem has been addressed in many attempts by replacing the hydrophobic groups bound to the QDs surface with more polar functional groups.272 On the other hand, ligand exchange may alter the chemical and physical states of the QD surface atoms and lead to a lower fluorescence efficiency of QDs. Thus, there is a need for simple synthetic routes to water-soluble QDs of controlled size and surface functionality.273 The belowdiscussed examples nicely demonstrate that native CD-modified inorganic nanoparticles offer a promising way to develop multifunctional nanoparticles for biomedical applications, molecular recognition, and sensing in water environment Cyclodextrins, as a well-known molecular host, have been used as an ideal functional molecule to improve the solubility,

Figure 42. Synthetic procedure for the formation of β-CD−CdSe QDs. (Reproduced with permission from ref 279. Copyright 2011 Wiley.)

the QDs. The replacement of the initial TOPO ligands with ferrocene derivatives caused a decrease of the luminescence quantum yields of QDs, likely due to electron transfer processes occurring between the QD and the ferrocene units. The reversibility of the phase transfer was demonstrated by the addition of naphthalene or adamantine derivatives to the aqueous phase containing CD−ferrocene-coated QDs. In turn,

Figure 41. Detection of phenols isomers by changing CD coating in the α-CD/CdSe/ZnS system via fluorescence intensity quenching. (Reprinted with permission from ref 277. Copyright 2008 American Chemical Society.) 13487


Chemical Reviews

Review

Figure 43. Illustration of the utilization of a β-CD-modified CdSe/ZnS QDs system (a) for sensing of organic analytes by a competitive FRET assay using with receptor-bound Rhodamine B. (b) Analysis of p-nitrophenol using an electron transfer quenching route. (Reprinted with permission from ref 280. Copyright 2009 American Chemical Society.) (c) Selective enantiorecognition of L-Penicillamine and D-Penicillamine. (Reprinted with permission from ref 281. Copyright 2017 Springer.) (d) Determination of ascorbic acid. (Reprinted with permission from ref 283. Copyright 2015 Royal Chemical Society.)

Figure 44. Illustration of the mechanism for ATP detection using β-CD−CuInS2 QDs and aptamer. (Reprinted with permission from ref 284. Copyright 2017 Elsevier.)

Jin and co-workers reported on the synthesis of β-CD-modified CdSe QDs by directly replacing the oleic acid (Ole) on the QDs surface with β-CD in an alkaline aqueous solution (Figure 42).279 The resulted CdSe QDs were covalently attached to βCDs and exhibited high photoluminescence efficiency and stability. Moreover, detailed analysis of the effect of various inorganic ions on the photoluminescence properties of such system revealed that transition-metal ions (Ag+, Hg2+, Co2+, Zn2+) have efficiently quenched the restored fluorescence of βCD−CdSe QDs. The results demonstrated the potential utility

of this probe for the detection of these ions with wide linear range. Willner and co-workers nicely demonstrated that β-CDmodified CdSe/ZnS QDs can be used for optical sensing and chiroselective sensing of different organic substrates involving a fluorescence resonance energy transfer (FRET) or an electron transfer (ET) mechanism.280 CdSe/ZnS QDs were modified with functionalized boronic acid and subsequently linked to a β-CD molecule via the secondary vicinal hydroxyl groups of the sugar units. The hydrophobic cavity of β-CD was used to 13488


Chemical Reviews

Review

accommodate Rhodamine B dye that acted as an optical label. Such systems were utilized for direct sensing of organic substrates exhibiting electron-acceptor or electron-donor properties via electron transfer quenching of the luminescence of the QDs. For example, the FRET between the CdSe/ZnS QDs and Rhodamine B incorporated in the β-CD cavities was used for competitive analysis of adamantanecarboxylic acid and p-hydroxytoluene (Figure 43a). Moreover, the β-CD-functionalized QD/dye system was used for the chiroselective optical discrimination between D,L-phenylalanine and D,L-tyrosine enantiomers. The specific selection of aromatic chiral amino acid was explained by favored interactions of the phenyl ring with the β-CD receptor. The same β-CD-functionalized QDs were also used as direct luminescence sensors for the optical detection of p-nitrophenol using an ET quenching route (Figure 43b). In a similar manner, water-soluble CD-modified CdSe/ZnS QDs were utilized as selective fluorescent assays for the recognition of amino acid enantiomers.281,282 The selective enantiorecognition of L-Penicillamine and D-Penicillamine was accomplished by host−guest interaction between the penicillamines and the β-CD pockets on the QDs (Figure 43c). Another sensing system based on β-CD and CdSe/ZnS QDs was developed for determination of ascorbic acid (Figure 43d).283 In this case, the fluorescence of the QDs was quenched by the oxidized ascorbic acid. In turn, the β-CD−CuInS2 QDs have attracted attention as a new class of sensor for detection of adenosine-5-triphosphate (ATP) (Figure 44).284 A slight enhancement of fluorescence emission from β-CD−CuInS2 QDs was observed upon addition of ATP-binding aptamer due to the host−guest interaction between aptamer and β-CD. Further addition of ATP to the β-CD−CuInS2 QDs/aptamer system results in the formation of aptamer-ATP complexes, which entered into cavities of β-CD leading to further enhancement of the fluorescence. A combination of native CDs and semiconductor nanocrystals can also pave the way for other original functional materials. For example, α-, β-, and γ-CD appeared to act as bifunctional linkers when interacting with anatase TiO2 nanocrystals under UV light, resulting in super long TiO2-containing wires.285 These assemblies display mechanical flexibility, stable electronics, and rapid response/long lifetime under photoinduced current. More recently, Nichols and co-workers developed an efficient method for the preparation of 3D networks of hybrid β-CD−TiO2 fibers of potential applications as photocatalytic filters and scaffolds for biological and hybrid material growth.286,287 The authors demonstrated that TiO2 NPs initiate a photocatalytic reaction that results in a ring breaking and dehydration of the CD molecules in solution. The dehydration process exposes the hydrophobic regions of the CD molecule to aqueous solution, supplying the force that drives selfassembly. The networks display a hierarchical structure with the nanoparticles assembled into micrometer diameter fibers that are interconnected into centimeter-scale self-supporting networks (Figure 45). Selective transformation of organic compounds using metal oxide semiconductors as mediators is one of the current challenging methods in organic synthesis from the viewpoint of renewable energy and environmental applications.288 In this regard, application of native CDs as surface-coating agents for the formation of CD-coated semiconductor nanocrystals provides a wide perspective for designing new sustainable and environmentally acceptable photocatalytic systems. Inherent properties of CDs to form host−guest complexes with organic

Figure 45. Schematic illustration of native CDs-directed self-assembly of TiO2 nanoparticles into a 3D network of hybrid fibers. (Reprinted with permission from ref 287. Copyright 2013 Elsevier.)

molecules water environment provides a promising route to adsorption of organic molecules on the surface of metal oxide semiconductors in order to improve their interaction with photocatalytically active sites. This approach was nicely substantiated, for example, by highly efficient photocatalytic reduction of nitroaromatic compounds based on a β-CD−TiO2 host−guest system in water under sunlight irradiation.289 In particular, the nitroaromatic compounds were solubilized in water through encapsulation in β-CD and formed an inclusion complex, which was attached to TiO2 under sunlight irradiation. Subsequently, the reduction of the nitro group to the corresponding amine function was carried out in the hydrophobic cavity of β-CD. Interestingly, one-pot N-acylation and N-formylation of photocatalytically prepared amines was carried out in an aqueous medium using anhydride or triethyl orthoformate. In another work, β-CD/TiO2 nanocomposite was found to show effective activity in the photodegradation of a series of bisphenols290 and reduction of Cr(VI) in aqueous solutions.291 In addition, a multicomponent Ag/β-CD/TiO2 nanocomposite was applied to methylene blue degradation under UV irradiation, and the significant improvement in the photodegradation rate was observed in comparison to the respective Ag/TiO2 system.292 Very recently, it has been demonstrated that a nanocomposite based on ZnO and β-CD shows superior photocatalytic activity toward photocatalytic decoloration of Rhodamine B dye under solar light irradiation, which is due to the lower band-gap energy of ZnO in the ZnO/ β-CD system.293 The above-described various CD-modified semiconducting nanocrystals were prepared using wet synthetic procedures that require bulk solvents. Very recently, a novel bottom-up mechanochemical strategy to water-soluble amide/β-CDcoated ZnO NCs from well-defined oxozinc precursor was developed (Figure 46).294 In this work, a well-defined predesigned oxozinc benzamide cluster, [Zn 4 (μ 4 -O)(ONHCPh)6], was used as a very efficient precursor for the preparation of benzamide-coated ZnO NCs in a mild mechanochemical hydrolysis process. Ball milling of the [Zn4(μ4-O)(ONHCPh)6] cluster with a small amount of water led to the material that exhibited yellow solid state visible luminescence (Figure 47c). The subsequent grinding of the benzamide-coated ZnO NCs with β-CD resulted in the second-coordination sphere decoration by β-CD molecules and afforded water-soluble β-CD− benzamide-coated ZnO NCs. Interestingly, β-CD−benzamide-coated ZnO NCs also can be obtained by applying a one-step three-component mechanochemical procedure. The HRTEM images of the resulting ZnO 13489


Chemical Reviews

Review

Figure 46. Mechanochemical bottom-up synthesis of β-CD−benzamide-coated ZnO NCs and their second-sphere modification. (Reprinted with permission from ref 294. Copyright 2016 John Wiley & Sons.)

build a nanoscale assembly of α-CD-modified CQDs in the presence of derivatives of methyl viologen (MV2+).297 Timeresolved fluorescence decay and transient absorption spectroscopy provided insight for the electron transfer processes between CQDs and MV2+. In other study, the combination of N-doped carbon dots and β-CD through noncovalent interactions led the formation of nanocomposite that after electrodeposition on glassy carbon electrode exhibited effective electrochemical properties for enantioselective recognition of tryptophan enantiomers.298 In turn, graphene QDs are attached to the β-CD through H bonds formed between the oxygencontaining groups on GQDs and the hydroxyl groups on βCD.299 The β-CD/GQDs nanocomposite could be effectively electrodeposited onto a glassy carbon electrode and works as an electrochemical chiral interface for enantiorecognition of tryptophan isomers,299 detection of Vitamin C,300 and detection of 2-chlorophenol or 3-chlorophenol.301 Further functionalization of β-CD/GQDs nanocomposite with chitosan provides an efficient nanocatalyst toward electrooxidation of methanol in alkaline solution.302 The GQDs-based electrodes functionalized with chitosan and β-CD was further extended to the demonstration of novel electrochemical sensors for the detection of various physiological analytes such as uric acid, ascorbic acid, and dopamine.303 Another recent work demonstrated the formation of watersoluble β-CD/rGO nanocomposite (rGO = reduced graphene oxide) by a combination of β-CD and graphene oxide (GO) in the presence of hydrazine hydrate (Figure 48a).304 This composite was further cast on the surface of glassy carbon

Figure 47. HRTEM micrographs and particle size distribution of (a) benzamide-coated ZnO NCs dispersed in THF and (b) β-CD− benzamide-coated ZnO NCs dissolved in water. Milling jar containing benzamide-coated ZnO in (c) visible and (d) UV light. Surface modification process allows for separation of NCs while not affecting their core size or structure. (e) Minimal observed distance between NCs; length of the white bar (1.56 nm) equals double the height of the β-CD molecule (0.78 nm). (Reprinted with permission from ref 294. Copyright 2016 John Wiley & Sons.)

NCs showed the presence of aggregated spherical particles 3.3 ± 0.6 nm in diameter (Figure 47). The ZnO NCs were well separated from each other (in contrast to the benzamidecoated-ZnO NCs), and the minimal observed distance between the NCs corresponds to the double height of the β-CD molecule (Figure 47e). In recent years, fluorescent carbon-based nanoparticles, carbon quantum dots (CQDs),295 and graphene (GQDs)296 have emerged as both a new class of carbon nanomaterials and potential competitors to conventional semiconductor quantum dots due to their unique physicochemical, optical, and electronic properties. The latest reports demonstrate that CDs can also be effectively used as functional molecules to improve the solubility and bioavailability of various CQDs and GQDs. For example, the host−guest approach was used to

Figure 48. (a) Schematic illustration of the synthesis of β-CD/rGO nanocomposite and (b) its application for electrochemical detection of Pb2+ ions. (Reprinted with permission from ref 304. Copyright 2016 Springer.) 13490


Chemical Reviews

Review

Scheme 10. Fe3O4-Supported Cu(II)-β-CD-Catalyzed Homocoupling Reaction of Arylboronic Acids Synthesis of 1,2,3Triazoles

Figure 49. Morphology and phase characterization of the Fe3S4 NCs: (a) FESEM, (b) TEM, (c) XRD, (d) SAED, (e) HRTEM, and (f) Fouriertransformed XAFS functions in the R domain further illuminated the fcc Fe3S4 phase. (Inset) Cell structure of fcc Fe3S4. (Reprinted with permission from ref 307. Copyright 2013 Macmillan Publishing Ltd.)

selected-area electron diffraction (SAED) pattern, HRTEM, and X-ray diffraction (Figure 49). Due to the similar polymer shell−core structure and protection function to a natural bacterial magnetosome, as-prepared Fe3S4 NCs were tested as a drug delivery carrier. The loading capacity of 58.7% for magnetic guided delivery of chemotherapeutic drug doxorubicin was obtained. Another work revealed that β-CD−Fe3S4 NPs exhibited an enhanced and selective removal capacity toward Pb(II) in comparison with bare Fe3S4 NPs.308 Additionally, the magnetic properties of the synthesized Fe3S4 NPs allowed fast separation of sorbents from water. The authors stated that Pb(II) was removed from water through the formation of lead sulfide precipitates (galena) and surface adsorption. This research demonstrated that β-CD-stabilized Fe3S4 NPs can be a potential material for Pb(II) removal from wastewater.

electrode to fabricate a chemically modified electrode showing high electrochemical response to Pb2+ (Figure 48b). Moreover, the composition of β-CD and graphene nanosheets (GNs) can be utilized as a supporting material to construct Pt nanoclusters with unique morphologies.305 The interaction affinity of aqueous dispersion of β-CD/GNs with platinum was responsible for the formation of so-called nanodendritic hydrangea-like particles. Most importantly, it was found that the as-prepared Pt/GNs/β-CD hybrid exhibited higher electrocatalytic activities regarding methanol oxidation and better tolerance toward CO poisoning than Pt/GNs. 6.2. Magnetic Nanoparticles Coated by Native CDs

A combination of native CDs and magnetic nanoparticles can also pave the way for other functional materials. For example, the reaction of FeCl2 with γ-CD in the alkaline solution resulted in the formation of magnetic nanoparticles of maghemite γ-Fe2O3 entrapped in tiny pseudosingle crystals of γ-CD.306 In another work, Kaboudin et al. developed the synthetic procedure for the formation of a magnetic Fe3O4 nanoparticle-supported Cu(II)−β-CD complex catalyst by a coprecipitation method.181 This catalyst was utilized for the efficient homocoupling of arylboronic acids and synthesis of 1,2,3-triazoles through in situ azidation of arylboronic acids and subsequent click cyclization in water (Scheme 10). In turn, a ZrO2 nanoparticle-supported Cu(II)−β-CD complex was found to be an effective heterogeneous catalyst for the regioselective synthesis of N-2-alkylated 1,2,3-triazoles.182 Native cyclodextrins can also act as soft templates for the preparation of metal sulfide NPs. For example, monodispersive (with an average diameter of 80−100 nm) and uniform β-CDstabilized magnetic Fe3S4 NCs were fabricated from the onepot solvothermal reaction between Fe(acac)3, β-CD, thioacetamide, and polyethylene glycol (PEG).307 These Fe3S4 NCs were well crystallized with high purity as determined by the

7. CONCLUSIONS AND OUTLOOKS For decades, cyclodextrins chemistry has developed into a very attractive field of research. The unique properties of cyclodextrins, in particular, their ability to incorporate other molecules into their cavities in aqueous environment and propensity to act as molecular building blocks of complex supramolecular architectures, allow for exciting opportunities in developments of multifunctional materials and devices. Nevertheless, while the application of nonfunctionalized CDs in the field of host−guest chemistry have been widely explored, the chemistry involving interactions of CDs with metal ions or inorganic nanoparticles has remained an area much less exploited and has progressed relatively slowly. Moreover, the employment of CDs as molecular building blocks to fabricate both materials of desired functionality and devices has emerged as new research only recently. In this review, we described the developments in the field paying special attention to the 13491


Chemical Reviews

Review

biology, medicine, materials science, and novel devises fabrication. Moreover, the research and developments in the area of inorganic nanomaterials, such as metal, metal oxide, semiconductor, and magnetic nanoparticles, have emerged into a cutting edge multidisciplinary nanotechnology. In this regard, CDs as well-known “green” molecular hosts have been widely used as ideal functional molecules to improve the solubility, stability, and bioavailability of these inorganic nanoparticles. Notably, magnetic CD-coated QDs with codelivery ability have immense potential in the area of biomedicine including magnetic resonance imaging, drug delivery, and even cancer inhibition. As an alternative to metal chalcogenide semiconductor nanoparticles, the modification of carbon or graphene quantum dots with cyclodextrins provides a promising direction to emerging types of fluorescent nanomaterials. With increased recent worldwide interest in both green chemistry and eco-friendly materials nanotechnologies, more sustainable manufacturing routes to crystalline nanometric inorganic materials are of particular interest. In this regard, solvent-free mechanochemical approaches supported by ecofriendly cyclodextrins appear to be an exciting field for further development. Modification of metal or semiconductor nanocrystal surfaces with native CDs can pave the way toward novel biological tracers, sensors, catalysts, as well as optoelectronic nanodevices. Undoubtedly, further efforts are indispensable to search for novel CD-based metal systems and CD-modified inorganic nanoparticles and fully explore their properties in the applications-oriented research. The combination of CDs with metal ions and a vast array of inorganic nanoparticles can pave the way toward novel supramolecular architectures and many classes of novel useful environmentally friendly functional materials and devices. We hope that this review will increase the awareness of CD-based metal systems and accelerate the development of functional materials based on these eco-friendly macrocycles.

synthesis of native CD−metal and CD−inorganic nanoparticle systems and their applications in various areas of chemistry and materials science. In particular, we demonstrated that CDs appear as excellent molecules to provide various molecular and extended self-assembled structures as well as materials of desired functionalities. Initially, we update the research in the area of the secondsphere coordination chemistry of neutral metal complexes with nonfunctionalized cyclodextrins. Native CDs have been used as supramolecular host systems that can form a wide variety of noncovalent host−guest inclusion entities with a vast array of organometallic and inorganic complexes for over three decades. CDs acting as second-sphere coordination ligands provide molecular-level encapsulation as well as a steric barrier to their degradation or deactivation. Simultaneously, investigations on the solid-state and solution structure of these types supramolecular entities have been accompanied by their use in catalytic processes and bioactivity studies. Nevertheless, while the design of catalytic systems using supramolecular approaches is rapidly expanding the discipline, application of native CD− organometallics host−guest systems in supramolecular catalysis is progressing relatively slowly. In particular, photocatalytic systems based on this type of supramolecular complex still await exploration. Unmodified CDs have appeared as very effective organic building blocks for templating metal ions. The development of many CD−metal systems begins with an understanding of the discrete molecular entities that give rise to their formation, and our analysis indicates that the fundamental science of CD− metal complexes remains, particularly in solution, far from being exhausted. While significant progress has been made in the synthesis of well-defined CD-based metal complexes exhibiting various molecular structures and supramolecular topologies, exciting opportunities remain for functionalizing such materials to optimize their properties for specific applications. For example, the first reaction systems involving native CDs as site-directing ligands and magnetic metal ions provide an intrigue wide perspective for the design and development of novel molecular magnetic materials. Further extensive work on CD−metal complexes may open up new opportunities in development of innovative materials of desired functionalities. In particular, employment of CD-based metal complexes as both chiral catalysts for asymmetric synthesis and chiral receptors for enantioselective separation of small chiral molecular guests still awaits exploration in the near future. Native CDs in combination with metal ions have a tremendous potential for the design and preparation of new environmentally acceptable porous inorganic−organic functional materials, which has been substantiated by very recent examples of the first CD−MOFs materials. In this regard, CDs have emerged as excellent molecules to provide highly porous carbohydrate metal−organic frameworks by the combination with alkali-metal ions. CD−MOFs as a new class of highly porous materials have shown particular promise in adsorption of small gaseous or liquid molecules and as host templates to the construction of advanced functional nanomaterials. Approaches to encapsulate the therapeutic agents and improve the stability of CD−MOFs in an aqueous environment by incorporation of hydrophobic molecules have provided real progress toward using CD−MOFs in the biomedical field. We envision that research in this area, which requires joint effort from different areas of expertise, will expand greatly in the near future, and the effort will contribute to advances in chemistry,

AUTHOR INFORMATION Corresponding Author

*E-mail: [email protected]. ORCID

Daniel Prochowicz: 0000-0002-5003-5637 Janusz Lewiński: 0000-0002-3407-0395 Author Contributions §

D.P. and A.K.: These authors contributed equally to this work.

Notes

The authors declare no competing financial interest. Biographies Daniel Prochowicz received his Ph.D. degree in Chemistry from the Warsaw University of Technology in 2013 under the supervision of Professor Janusz Lewiń ski. His research interests center on coordination and metallo-supramolecular chemistry as well as development of efficient mechanochemical procedures for the preparation of coordination polymers and perovskites for solar cell devices. He currently works as a postdoctoral researcher, a Marie Curie Fellow, under the direction of Professor Michael Graetzel at the Ecole Polytechnique de Federale de Lausanne, where he is focusing on fabrication and characterization of perovskite solar cells. 13492


Chemical Reviews

Review

(11) Villiers, A. Proceedings of the Acadeḿ ie des Sciences. Bull. Soc. Chim. Paris 1891, 45, 468. (12) Schardinger, F. Wien. Klin. Wochenschr. 1904, 17, 207−209. (13) Crini, G. Review: A History of Cyclodextrins. Chem. Rev. 2014, 114, 10940−10975. (14) Jicsinszky, L.; Fenyvesi, E.In Cyclodextrin Derivatives; Szejtli, J., Osa, T., Eds.; Pergamon: New York, 1996. (15) Khan, A. R.; Forgo, P.; Stine, K. J.; D’Souza, V. T. Methods for Selective Modifications of Cyclodextrins. Chem. Rev. 1998, 98, 1977− 1996. (16) Bellia, F.; La Mendola, D.; Pedone, C.; Rizzarelli, E.; Saviano, M.; Vecchio, G. Selectively Functionalized Cyclodextrins and Their Metal Complexes. Chem. Soc. Rev. 2009, 38, 2756−2781. (17) Dodziuk, H. Cyclodextrins and their Complexes. Chemistry. Analytical Methods, Applications; Wiley-VCH, Verlag GmbH & Co. KGaA: Weinheim, Germany, 2006. (18) Harata, K. Structural Aspects of Stereodifferentiation in the Solid State. Chem. Rev. 1998, 98, 1803−1828. (19) Hingerty, B.; Saenger, W. Topography of Cyclodextrin Inclusion Complexes. Crystal and Molecular Structure of the Alpha-cyclodextrin-methanol-pentahydrate Complex. Disorder in a Hydrophobic Cage. J. Am. Chem. Soc. 1976, 98, 3357−3365. (20) Harada, A.; Okada, M.; Li, J.; Kamachi, M. Preparation and Characterization of Inclusion Complexes of Poly(propylene glycol) with Cyclodextrins. Macromolecules 1995, 28, 8406−8411. (21) Kokkinou, A.; Makedonopoulou, S.; Mentzafos, D. The Crystal Structure of the 1:1 Complex of β-cyclodextrin with Trans-cinnamic Acid. Carbohydr. Res. 2000, 328, 135−140. (22) Harata, K. The Structure of the Cyclodextrin Complex. V. Crystal Structures of α-Cyclodextrin Complexes with p-Nitrophenol and p-Hydroxybenzoic Acid. Bull. Chem. Soc. Jpn. 1977, 50, 1416− 1424. (23) Uekama, K.; Hirayama, F.; Irie, T. Cyclodextrin Drug Carrier Systems. Chem. Rev. 1998, 98, 2045−2076. (24) Hirayama, F.; Uekama, K. Cyclodextrin-Based Controlled Drug Release System. Adv. Drug Delivery Rev. 1999, 36, 125−141. (25) Kurkov, S. V.; Loftsson, T. Cyclodextrins. Int. J. Pharm. 2013, 453, 167−180. (26) Zhang, J.; Ma, P. X. Cyclodextrin-Based Supramolecular Systems for Drug Delivery: Recent Progress and Future Perspective. Adv. Drug Delivery Rev. 2013, 65, 1215−1233. (27) Hu, Q.-D.; Tang, G.-P.; Chu, P. K. Cyclodextrin-Based Host− Guest Supramolecular Nanoparticles for Delivery: From Design to Applications. Acc. Chem. Res. 2014, 47, 2017−2025. (28) Sharma, N.; Baldi, A. Exploring Versatile Applications of Cyclodextrins: An Overview. Drug Delivery 2016, 23, 729−747. (29) Webber, M. J.; Langer, R. Drug Delivery by Supramolecular Design. Chem. Soc. Rev. 2017, DOI: 10.1039/C7CS00391A. (30) Cutrone, G.; Casas-Solvas, J. M.; Vargas-Berenguel, A. Cyclodextrin-Modified Inorganic Materials for the Construction of Nanocarriers. Int. J. Pharm. 2017, 531, 621. (31) Harada, A. Cyclodextrin-Based Molecular Machines. Acc. Chem. Res. 2001, 34, 456−464. (32) Takahashi, K.; Hattori, K. J. Asymmetric Reactions with Cyclodextrins. J. Inclusion Phenom. Mol. Recognit. Chem. 1994, 17, 1− 24. (33) Takahashi, K. Organic Reactions Mediated by Cyclodextrins. Chem. Rev. 1998, 98, 2013−2033. (34) Marinescu, L.; Bols, M. Cyclodextrins as Supramolecular Organo-Catalysts. Curr. Org. Chem. 2010, 14, 1380−1398. (35) Macaev, F.; Boldescu, V. Cyclodextrins in Asymmetric and Stereospecific Synthesis. Symmetry 2015, 7, 1699−1720. (36) Denicourt-Nowicki, A.; Roucoux, A. Noble Metal Nanoparticles Stabilized by Cyclodextrins: A Pertinent Partnership for Catalytic Applications. Curr. Org. Chem. 2010, 14, 1266−1283. (37) Gramage-Doria, R.; Armspach, D.; Matt, D. Metallated Cavitands (calixarenes, resorcinarenes, cyclodextrins) with Internal Coordination Sites. Coord. Chem. Rev. 2013, 257, 776−816.

Arkadiusz Kornowicz received his MSc. degree in Chemistry from the Warsaw University of Technology in 2007 under the supervision of Professor Janusz Lewiń ski. His research interests center on coordination, molecular magnetic properties, activation of small molecules, and metallo-supramolecular chemistry as well as in nanotechnology. He is currently finishing his Ph.D. thesis at his Alma Mater under the supervision of Professor Janusz Lewiński. His dissertation is devoted to the coordinaton chemistry of native cyclodextrins application of CD−metal-based systems in catalysis and materials science. Janusz Lewiński received his Ph.D. degree from the Warsaw University of Technology (WUT) in 1990. Since 2007 he has been Full Professor at the Faculty of Chemistry WUT as well as at the Institute of Physical Chemistry of the Polish Academy of Sciences. His scientific activity has multidisciplinary character as his interests range from fundamental inorganic and organometallic chemistry to catalysis, materials science, and nanoscience. A distinctive feature of research in his team is transferring curiosity-driven molecular-level fundamental research to practical application in the synthesis of functional materials. He has coauthored over 120 papers and 20 patent applications. In 2016, he cofounded Noanoxo Incorporated, a company devoted to the development of heavy-metal-free quantum dots. His research has been recognized with several awards including the Maria SkłodowskaCurie Award of the Polish Academy of Sciences (2008) and the WUT Scientific Prize (2011). He has been a member of the European Academy of Science since 2013 and a Fellow of the Royal Society of Chemistry (2015).

ACKNOWLEDGMENTS The authors acknowledge the Foundation for Polish Science Team Program cofinanced by the European Union under the European Regional Development Fund TEAM/2016-2/14 and the Ministry of Science and Higher Education within the Iuventus Plus Programme (IP/2015 064274; D.P.) for financial support. REFERENCES (1) Gale, P.; Steed, J. Supramolecular Chemistry: From Molecules to Nanomaterials; Wiley-VCH Verlag GmbH & Co. KGaA: Weinheim, 2012. (2) Busseron, E.; Ruff, Y.; Moulin, E.; Giuseppone, N. Supramolecular Self-Assemblies as Functional Nanomaterials. Nanoscale 2013, 5, 7098−7140. (3) Pedersen, C. J. The Discovery of Crown Ethers (Nobel Lecture). Angew. Chem., Int. Ed. Engl. 1988, 27, 1021−1027. (4) Krakowiak, K. E.; Bradshaw, J. S.; Zamecka-Krakowiak, D. J. Synthesis of Aza-crown Ethers. Chem. Rev. 1989, 89, 929−972. (5) Lehn, J.-M. Supramolecular Chemistry-Scope and Perspectives Molecules, Supermolecules, and Molecular Devices (Nobel Lecture). Angew. Chem., Int. Ed. Engl. 1988, 27, 89−112. (6) Wei, A. Calixarene-Encapsulated Nanoparticles: Self-Assembly into Functional Nanomaterials. Chem. Commun. 2006, 1581−1591. (7) Barrow, S. J.; Kasera, S.; Rowland, M. J.; del Barrio, J.; Scherman, O. A. Cucurbituril-Based Molecular Recognition. Chem. Rev. 2015, 115, 12320−12406. (8) Szejtli, J. Introduction and General Overview of Cyclodextrin Chemistry. Chem. Rev. 1998, 98, 1743−1754. (9) Saenger, W.; Jacob, J. l.; Gessler, K.; Steiner, T.; Hoffmann, D.; Sanbe, H.; Koizumi, K.; Smith, S. M.; Takaha, T. Structures of the Common Cyclodextrins and Their Larger Analogues Beyond the Doughnut. Chem. Rev. 1998, 98, 1787−1802. (10) Chen, G.; Jiang, M. Cyclodextrin-Based Inclusion Complexation Bridging Supramolecular Chemistry and Macromolecular SelfAssembly. Chem. Soc. Rev. 2011, 40, 2254−2266. 13493


Chemical Reviews

Review

(38) Hapiot, F.; Bricout, H.; Menuel, S.; Tilloy, S.; Monflier, E. Recent Breakthroughs in Aqueous Cyclodextrin-Assisted Supramolecular Catalysis. Catal. Sci. Technol. 2014, 4, 1899−1908. (39) Noël, S.; Léger, B.; Ponchel, A.; Philippot, K.; DenicourtNowicki, A.; Roucoux, A.; Monflier, E. Cyclodextrin-Based Systems for the Stabilization of Metallic (0) Nanoparticles and their Versatile Applications in Catalysis. Catal. Today 2014, 235, 20−32. (40) Hapiot, F.; Monflier, E. Unconventional Approaches Involving Cyclodextrin-Based, Self-Assembly-Driven Processes for the Conversion of Organic Substrates in Aqueous Biphasic Catalysis. Catalysts 2017, 7, 173. (41) Hapiot, F.; Menuel, S.; Ferreira, M.; Léger, B.; Bricout, H.; Tilloy, S.; Monflier, E. Catalysis in Cyclodextrin-Based Unconventional Reaction Media: Recent Developments and Future Opportunities. ACS Sustainable Chem. Eng. 2017, 5, 3598−3606. (42) Zhang, P.; Meijide Suárez, J.; Driant, T.; Derat, E.; Zhang, Y.; Ménand, M.; Roland, S.; Sollogoub, M. Cyclodextrin Cavity-Induced Mechanistic Switch in Copper-Catalyzed Hydroboration. Angew. Chem., Int. Ed. 2017, 56, 10821. (43) Breslow, R.; Dong, S. D. Biomimetic Reactions Catalyzed by Cyclodextrins and Their Derivatives. Chem. Rev. 1998, 98, 1997−2012. (44) Rizzarelli, E.; Saviano, M.; Vecchio, G. Metal Complexes of Functionalized Cyclodextrins as Enzyme Models and Chiral Receptors. Coord. Chem. Rev. 1999, 188, 343−364. (45) Singleton, M. L.; Reibenspies, J. H.; Darensbourg, M. Y. A Cyclodextrin Host/Guest Approach to a Hydrogenase Active Site Biomimetic Cavity. J. Am. Chem. Soc. 2010, 132, 8870−8871. (46) Bistri, O.; Reinaud, O. Supramolecular Control of Transition Metal Complexes in Water by a Hydrophobic Cavity: A Bio-inspired Strategy. Org. Biomol. Chem. 2015, 13, 2849−2865. (47) Rebilly, J.-N.; Colasson, B.; Bistri, O.; Over, D.; Reinaud, O. Biomimetic Cavity-Based Metal Complexes. Chem. Soc. Rev. 2015, 44, 467−489. (48) Kuah, E.; Toh, S.; Yee, J.; Ma, Q.; Gao, Z. Enzyme Mimics: Advances and Applications. Chem. - Eur. J. 2016, 22, 8404−8430. (49) Bols, M.; Wang, B. Artificial Metallooxidases from Cyclodextrin Diacids. Chem. - Eur. J. 2017, DOI: 10.1002/chem.201702530. (50) Nakahata, M.; Takashima, Y.; Yamaguchi, H.; Harada, A. Redoxresponsive Self-healing Materials Formed from Host−Guest Polymers. Nat. Commun. 2011, 2, 511. (51) Chen, Y.; Liu, Y. Cyclodextrin-based Bioactive Supramolecular Assemblies. Chem. Soc. Rev. 2010, 39, 495−505. (52) Ogoshi, T.; Harada, A. Chemical Sensors Based on Cyclodextrin Derivatives. Sensors 2008, 8, 4961−4982. (53) Villalobos, L. F.; Huang, T.; Peinemann, K.-V. Cyclodextrin Films with Fast Solvent Transport and Shape-Selective Permeability. Adv. Mater. 2017, 29, 1606641. (54) Morin-Crini, N.; Winterton, P.; Fourmentin, S.; Wilson, L. D.; Fenyvesi, É.; Crini, G. Water-Insoluble β-Cyclodextrin−Epichlorohydrin Polymers for Removal of Pollutants From Aqueous Solutions by Sorption Processes using Batch Studies: A Review of Inclusion Mechanisms. Prog. Polym. Sci. 2017, DOI: 10.1016/j.progpolymsci.2017.07.004. (55) Hapiot, F.; Tilloy, S.; Monflier, E. Cyclodextrins as Supramolecular Hosts for Organometallic Complexes. Chem. Rev. 2006, 106, 767−781. (56) Liu, Z.; Schneebeli, S. T.; Stoddart, J. F. Second-Sphere Coordination Revisited. Chimia 2014, 68, 315−320. (57) Wu, Y.; Shi, R.; Wu, Y.-L.; Holcroft, J. M.; Liu, Z.; Frasconi, M.; Wasielewski, M. R.; Li, H.; Stoddart, J. F. Complexation of Polyoxometalates with Cyclodextrins. J. Am. Chem. Soc. 2015, 137, 4111−4118. (58) Chankvetadze, B. Combined Approach Using Capillary Electrophoresis and NMR Spectroscopy for An Understanding of Enantioselective Recognition Mechanisms by Cyclodextrins. Chem. Soc. Rev. 2004, 33, 337−347. (59) Liu, Y.; Chen, Y. Cooperative Binding and Multiple Recognition by Bridged Bis(β-Cyclodextrin)s with Functional Linkers. Acc. Chem. Res. 2006, 39, 681−691.

(60) Shahgaldian, P.; Pieles, U. Cyclodextrin Derivatives as Chiral Supramolecular Receptors for Enantioselective Sensing. Sensors 2006, 6, 593−615. (61) König, W. A. Gas Chromatographic Enantiomer Separation with Modified Cyclodextrins; Hüthig: Heidelberg, 1992. (62) Scriba, G. K. E. Cyclodextrins in Capillary Electrophoresis Enantioseparations−Recent Developments and Applications. J. Sep. Sci. 2008, 31, 1991−2011. Cserháti, T. New applications of cyclodextrins in electrically driven chromatographic systems: a review. Biomed. Chromatogr. 2008, 22, 563−571. (63) Xiao, Y.; Ng, S.-C.; Tan, T. T.; Wang, Y. Recent Development of Cyclodextrin Chiral Stationary Phases and their Applications in Chromatography. J. Chromatogr. A 2012, 1269, 52−68. (64) Escuder-Gilabert, L.; Martin-Biosca, Y.; Medina-Hernandez, M. J.; Sagrado, S. Cyclodextrins in Capillary Electrophoresis: Recent Developments and New Trends. J. Chromatogr. A 2014, 1357, 2−23. (65) Zhou, J.; Tang, J.; Tang, W. Recent Development of Cationic Cyclodextrins for Chiral Separation. TrAC, Trends Anal. Chem. 2015, 65, 22−29. (66) Zhu, Q.; Scriba, G. K. E. Advances in the Use of Cyclodextrins as Chiral Selectors in Capillary Electrokinetic Chromatography: Fundamentals and Applications. Chromatographia 2016, 79, 1403− 1435. (67) Adly, F. G.; Antwi, N. Y.; Ghanem, A. CyclodextrinFunctionalized Monolithic Capillary Columns: Preparation and Chiral Applications. Chirality 2016, 28, 97−109. (68) Olives, A. I.; Gonzalez-Ruiz, V.; Martín, M. A. Sustainable and Eco-Friendly Alternatives for Liquid Chromatographic Analysis. ACS Sustainable Chem. Eng. 2017, 5, 5618−5634. (69) Schmidt, B. V. K. J.; Barner-Kowollik, C. Dynamic Macromolecular Material Design − The Versatility of Cyclodextrin Based Host/Guest Chemistry. Angew. Chem., Int. Ed. 2017, 56, 8350−8369. (70) Philp, D.; Stoddart, J. F. Self-Assembly in Natural and Unnatural Systems. Angew. Chem., Int. Ed. Engl. 1996, 35, 1154−1196. (71) Xue, M.; Yang, Y.; Chi, X.; Yan, X.; Huang, F. Development of Pseudorotaxanes and Rotaxanes: From Synthesis to StimuliResponsive Motions to Applications. Chem. Rev. 2015, 115, 7398− 7501. (72) Wenz, G.; Han, B.-H.; Müller, A. Cyclodextrin Rotaxanes and Polyrotaxanes. Chem. Rev. 2006, 106, 782−817. (73) Yue, L.; Wang, S.; Zhou, D.; Zhang, H.; Li, B.; Wu, L. Flexible Single-Layer Ionic Organic−Inorganic Frameworks Towards Precise Nano-size Separation. Nat. Commun. 2016, 7, 10742. (74) Girek, T. Cyclodextrin-Based Rotaxanes. J. Inclusion Phenom. Mol. Recognit. Chem. 2012, 74, 1−21. (75) Garcia-Rio, L.; Otero-Espinar, F. J.; Luzardo-Alvarez, A.; BlancoMendez, J. Cyclodextrin Based Rotaxanes, Polyrotaxanes and Polypseudorotaxanes and Their Biomedical Applications. Curr. Top. Med. Chem. 2014, 14, 478−493. (76) Zhao, Q.; Wang, Y.; Yan, Y.; Huang, J. Smart Nanocarrier: SelfAssembly of Bacteria-like Vesicles with Photoswitchable Cilia. ACS Nano 2014, 8, 11341−11349. (77) Zhang, B.; Yue, L.; Wang, Y.; Yang, Y.; Wu, L. A Novel Singleside Azobenzene-grafted Anderson-type Polyoxometalate for Recognition-induced Chiral Migration. Chem. Commun. 2014, 50, 10823− 10826. (78) Zheng, X.; Wang, D.; Shuai, Z.; Zhang, X. Molecular Dynamics Simulations of the Supramolecular Assembly between an AzobenzeneContaining Surfactant and α-Cyclodextrin: Role of Photoisomerization. J. Phys. Chem. B 2012, 116, 823−832. (79) Wang, D.; Wagner, M.; Butt, H.-J.; Wu, S. Supramolecular Hydrogels Constructed by Red-Light-Responsive Host−Guest Interactions for Photo-Controlled Protein Release in Deep Tissue. Soft Matter 2015, 11, 7656−7662. (80) Samanta, A.; Stuart, M. C.; Ravoo, B. J. Photoresponsive Capture and Release of Lectins in Multilamellar Complexes. J. Am. Chem. Soc. 2012, 134, 19909−19914. 13494


Chemical Reviews

Review

(81) Gong, Y.-H.; Yang, J.; Cao, F.-Y.; Zhang, J.; Cheng, H.; Zhuo, R.-X.; Zhang, X.-Z. Photoresponsive Smart Template for Reversible Cell Micropatterning. J. Mater. Chem. B 2013, 1, 2013−2017. (82) Wang, D.; Wu, S. Red-Light-Responsive Supramolecular Valves for Photocontrolled Drug Release from Mesoporous Nanoparticles. Langmuir 2016, 32, 632−636. (83) Song, Q.; Li, F.; Tan, X.; Yang, L.; Wang, Z.; Zhang, X. Supramolecular Polymerization of Supramonomers: A Way for Fabricating Supramolecular Polymers. Polym. Chem. 2014, 5, 5895− 5899. (84) Zhu, L.; Yan, H.; Ang, C. Y.; Nguyen, K. T.; Li, M.; Zhao, Y. Photoswitchable Supramolecular Catalysis by Interparticle Host-Guest Competitive Binding. Chem. - Eur. J. 2012, 18, 13979−13983. (85) Heinzmann, C.; Weder, C.; de Espinosa, L. M. Supramolecular Polymer Adhesives: Advanced Materials Inspired by Nature. Chem. Soc. Rev. 2016, 45, 342−358. (86) Yamaguchi, H.; Kobayashi, Y.; Kobayashi, R.; Takashima, Y.; Hashidzume, A.; Harada, A. Photoswitchable Gel Assembly Based on Molecular Recognition. Nat. Commun. 2012, 3, 603. (87) Tamesue, S.; Takashima, Y.; Yamaguchi, H.; Shinkai, S.; Harada, A. Photoswitchable Supramolecular Hydrogels Formed by Cyclodextrins and Azobenzene Polymers. Angew. Chem., Int. Ed. 2010, 49, 7461−7164. (88) Tomatsu, I.; Hashidzume, A.; Harada, A. Contrast Viscosity Changes upon Photoirradiation for Mixtures of Poly(acrylic acid)Based α-Cyclodextrin and Azobenzene Polymers. J. Am. Chem. Soc. 2006, 128, 2226−2227. (89) Takashima, Y.; Hatanaka, S.; Otsubo, M.; Nakahata, M.; Kakuta, T.; Hashidzume, A.; Yamaguchi, H.; Harada, A. Expansion− Contraction of Photoresponsive Artificial Muscle Regulated by Host−Guest Interactions. Nat. Commun. 2012, 3, 1270. (90) Nakahata, M.; Takashima, Y.; Hashidzume, A.; Harada, A. Redox-Generated Mechanical Motion of a Supramolecular Polymeric Actuator Based on Host-Guest Interactions. Angew. Chem., Int. Ed. 2013, 52, 5731−5735. (91) Nakamura, T.; Takashima, Y.; Hashidzume, A.; Yamaguchi, H.; Harada, A. A Metal−Ion-Responsive Adhesive Material via Switching of Molecular Recognition Properties. Nat. Commun. 2014, 5, 4622. (92) Harada, A.; Takashima, Y.; Nakahata, M. Supramolecular Polymeric Materials via Cyclodextrin−Guest Interactions. Acc. Chem. Res. 2014, 47, 2128−2140. (93) Harada, A.; Takahashi, S. Preparation and Properties of Cyclodextrin−Ferrocene Inclusion Complexes. J. Chem. Soc., Chem. Commun. 1984, 645−646. (94) Fernandes, J. A.; Lima, S.; Braga, S. S.; Ribeiro-Claro, P.; Rodríguez-Borges, J. E.; Teixeira, C.; Pillinger, M.; Teixeira-Dias, J. J. C.; Goncalves, I. S. Inclusion Complex Formation of Diferrocenyldimethylsilane with β-Cyclodextrin. J. Organomet. Chem. 2005, 690, 4801−4808. (95) Fernandes, J. A.; Lima, S.; Braga, S. S.; Pillinger, M.; RibeiroClaro, P.; Rodríguez-Borges, J. E.; Lopes, A. D.; Teixeira-Dias, J. J. C.; Goncalves, I. S. Inclusion Complexation of Dimeric and Trimeric Oligo(ferrocenyldimethylsilanes) with γ-Cyclodextrin. Organometallics 2005, 24, 5673−5677. (96) Yan, Q.; Yuan, J.; Cai, Z.; Xin, Y.; Kang, Y.; Yin, Y. VoltageResponsive Vesicles Based on Orthogonal Assembly of Two Homopolymers. J. Am. Chem. Soc. 2010, 132, 9268−9270. (97) Szillat, F.; Schmidt, B. V. K. J.; Hubert, A.; Barner-Kowollik, C.; Ritter, H. Redox-Switchable Supramolecular Graft Polymer Formation via Ferrocene−Cyclodextrin Assembly. Macromol. Rapid Commun. 2014, 35, 1293−1300. (98) Schmidt, B. V. K. J.; Kugele, D.; von Irmer, J.; Steinkoenig, J.; Mutlu, H.; Rüttiger, C.; Hawker, C. J.; Gallei, M.; Barner-Kowollik, C. Dual-Gated Supramolecular Star Polymers in Aqueous Solution. Macromolecules 2017, 50, 2375−2386. (99) Odagaki, Y.; Hirotsu, K.; Higuchi, T.; Harada, A.; Takahashi, S. X-Ray Structure of the α-Cyclodextrin−Ferrocene (2:1) Inclusion Compound. J. Chem. Soc., Perkin Trans. 1 1990, 1230−1233.

(100) Klingert, B.; Rihs, G. Molecular Encapsulation of Transition Metal Complexes in Cyclodextrins. Part 2. Synthesis and Crystal Structures of 2:1 Adducts between α-Cyclodextrin and Metallocenium Hexafluorophosphates ((η5-C5H5)2M)PF6(M = Fe, Co, Rh). J. Inclusion Phenom. Mol. Recognit. Chem. 1991, 10, 255−265. (101) Klingert, B.; Rihs, G. Molecular Encapsulation of TransitionMetal Complexes in Cyclodextrins. Synthesis and X-ray Crystal Structure of ((η5-C5H5)Fe(η6-C6H6))PF6·2α-CD·8H2O. Organometallics 1990, 9, 1135−1141. (102) Harada, A.; Hu, Y.; Yamamoto, S.; Takahashi, S. Preparation and Properties of Inclusion Compounds of Ferrocene and its Derivatives with Cyclodextrins. J. Chem. Soc., Dalton Trans. 1988, 729−732. (103) Bakhtiar, R.; Kaifer, A. E. Mass Spectrometry Studies on the Complexation of Several Organometallic Complexes by α- and βCyclodextrins. Rapid Commun. Mass Spectrom. 1998, 12, 111−114. (104) Liu, Y.; Zhong, R. Q.; Zhang, H. Y.; Song, H. B. A Unique Tetramer of 4:5 β-Cyclodextrin−Ferrocene in the Solid State. Chem. Commun. 2005, 2211−2213. (105) Lippold, I.; Vlay, K.; Görls, H.; Plass, W. Cyclodextrin Inclusion Compounds of Vanadium Complexes: Structural Characterization and Catalytic Sulfoxidation. J. Inorg. Biochem. 2009, 103, 480− 486. (106) Lippold, I.; Görls, H.; Plass, W. New Aspects for Modeling Supramolecular Interactions in Vanadium Haloperoxidases: β-Cyclodextrin Inclusion Compounds of cis-Dioxovanadium(V) Complexes. Eur. J. Inorg. Chem. 2007, 2007, 1487−1491. (107) Harada, A.; Saeki, K.; Takahashi, S. Preparation and Properties of Inclusion Compounds of (η6-arene)tricarbonylchromium(0) Complexes with Cyclodextrins. Organometallics 1989, 8, 730−733. (108) Harada, A.; Takeuchi, M.; Takahashi, S. Preparation and Properties of Inclusion Compounds of η3-Allylpalladium Complexes with Cyclodextrins. Chem. Lett. 1986, 15, 1893−1894. (109) Harada, A.; Takeuchi, M.; Takahashi, S. Preparation and Properties of Inclusion Compounds of η3-Allylpalladium Complexes with Cyclodextrins. Bull. Chem. Soc. Jpn. 1988, 61, 4367−4370. (110) Alston, D. R.; Slawin, A. M. Z.; Stoddart, J. F.; Williams, D. J. Cyclodextrins as Second Sphere Ligands for Transition Metal Complexes- The X-Ray Crystal Structure of (Rh(cod)(NH3)2·αcyclodextrin) (PF6)·6H2O. Angew. Chem., Int. Ed. Engl. 1985, 24, 786− 787. (111) Alston, D. R.; Ashton, P. R.; Lilley, T. H.; Stoddart, J. F.; Zarzycki, R. Second-Sphere Coordination of Carboplatin and Rhodium Complexes by Cyclodextrins (cyclomalto-oligosaccharides). Carbohydr. Res. 1989, 192, 259−281. (112) Shimada, M.; Harada, A.; Takahashi, S. Reactions of Organometallic Complexes Included in Cyclodextrins: Reactivity of Alkyldicarbonyl(η 5 -Cyclopentadienyl)iron Complexes towards Carbon Monoxide and Sulphur Dioxide in the Solid State. J. Chem. Soc., Chem. Commun. 1991, 114, 263−264. (113) Song, L.; Meng, Q.; You, X. Preparation and Properties of Inclusion Compound of Cyclopentadienylmanganese Tricarbonyl Complex with a SS-Cyclodextrin Dime. J. Organomet. Chem. 1995, 498, C1−C5. (114) Harada, A.; Saeki, K.; Takahashi, S. Preparation and Properties of Inclusion Compounds of (.eta.6-arene)tricarbonylchromium(0) Complexes with Cyclodextrins. Organometallics 1989, 8, 730−733. (115) Braga, S. S.; Gonçalves, I. S.; Lopes, A. D.; Pillinger, M.; Rocha, J.; Romão, C. C.; Teixeira-Dias, J. J. C. Encapsulation of Half-Sandwich Complexes of Molybdenum with β-Cyclodextrin. J. Chem. Soc. Dalt. Trans. 2000, 8, 2964−2968. (116) Braga, S. S.; Mokal, V.; Paz, F. A. A.; Pillinger, M.; Branco, A. F.; Sardão, V. A.; Diogo, C. V.; Oliveira, P. J.; Marques, M. P. M.; Romão, C. C.; et al. Synthesis, Characterisation and Antiproliferative Studies of Allyl(dicarbonyl)(cyclopentadienyl)-molybdenum Complexes and Cyclodextrin Inclusion Compounds. Eur. J. Inorg. Chem. 2014, 2014, 5034−5045. (117) Steinborn, D.; Junicke, H. Carbohydrate Complexes of Platinum-Group Metals. Chem. Rev. 2000, 100, 4283−4318. 13495


Chemical Reviews

Review

Second-Sphere Coordination. J. Am. Chem. Soc. 2016, 138, 11643− 11653. (135) Assaf, K. I.; Ural, M. S.; Pan, F.; Georgiev, T.; Simova, S.; Rissanen, K.; Gabel, D.; Nau, W. M. Water Structure Recovery in Chaotropic Anion Recognition: High-Affinity Binding of Dodecaborate Clusters to γ-Cyclodextrin. Angew. Chem., Int. Ed. 2015, 54, 6852−6856. (136) Warneke, J.; Jenne, C.; Bernarding, J.; Azov, V. A.; Plaumann, M. Evidence for an Intrinsic Binding Force Between Dodecaborate Dianions and Receptors with Hydrophobic Binding Pockets. Chem. Commun. 2016, 52, 6300−6303. (137) Benner, K.; Klüfers, P.; Schuhmacher, J. A Molecular Composite Constructed in Aqueous Alkaline Solution from a Double Six-Ring Silicate and α-Cyclodextrin. Angew. Chem., Int. Ed. Engl. 1997, 36, 743−745. (138) Shibu, E. S.; Pradeep, T. Quantum Clusters in Cavities: Trapped Au15 in Cyclodextrins. Chem. Mater. 2011, 23, 989−999. (139) Moussawi, M. A.; Leclerc-Laronze, N.; Floquet, S.; Abramov, P. A.; Sokolov, M. N.; Cordier, S.; Ponchel, A.; Monflier, E.; Bricout, H.; Landy, D.; Haouas, M.; Marrot, J.; Cadot, E. Polyoxometalate, Cationic Cluster, and γ-Cyclodextrin: From Primary Interactions to Supramolecular Hybrid Materials. J. Am. Chem. Soc. 2017, 139, 12793−12803. (140) Norkus, E. Metal Ion Complexes with Native Cyclodextrins. An Overview. J. Inclusion Phenom. Mol. Recognit. Chem. 2009, 65, 237− 248. (141) Prochowicz, D.; Kornowicz, A.; Justyniak, I.; Lewiński, J. Metal Complexes Based on Cyclodextrins: Synthesis and Structural Diversity. Coord. Chem. Rev. 2016, 306, 331−345. (142) Brusseau, M. L.; Wang, X.; Wang, W.-Z. Simultaneous Elution of Heavy Metals and Organic Compounds from Soil by Cyclodextrin. Environ. Sci. Technol. 1997, 31, 1087−1092. (143) Landy, D.; Mallard, I.; Ponchel, A.; Monflier, E.; Fourmentin, S. Remediation Technologies Using Cyclodextrins: An Overview. Environ. Chem. Lett. 2012, 10, 225−237. (144) Gelb, R. I.; Schwartz, L. M.; Bradshaw, J. J.; Laufer, D. A. Acid Dissociation of Cyclohexaamylose and Cycloheptaamylose. Bioorg. Chem. 1980, 9, 299−304. (145) Kubik, S. Anion Recognition in Water. Chem. Soc. Rev. 2010, 39, 3648−3663. (146) Song, L. X.; Bai, L.; Xu, X. M.; He, J.; Pan, S. Z. Inclusion Complexation, Encapsulation Interaction and Inclusion Number in Cyclodextrin Chemistry. Coord. Chem. Rev. 2009, 253, 1276−1284. (147) Matsui, Y.; Kurita, T.; Date, Y. Complexes of Copper(II) with Cyclodextrins. Bull. Chem. Soc. Jpn. 1972, 45, 3229. (148) Matsui, Y.; Kurita, T.; Yagi, M.; Okayama, T.; Mochida, K.; Date, Y. The Formation and Structure of Copper(II) Complexes with Cyclodextrins in an Alkaline Solution. Bull. Chem. Soc. Jpn. 1975, 48, 2187−2191. (149) Mochida, K.; Matsui, Y. Kinetic Study on The Formation of a Binuclear Complex Between Copper(II) and Cyclodextrin. Chem. Lett. 1976, 5, 963−966. (150) McNamara, M.; Russell, N. R. FT-IR and Raman Spectra of a Series of Metallo-β-Cyclodextrin Complexes. J. Inclusion Phenom. Mol. Recognit. Chem. 1991, 10, 485−495. (151) Bose, P. K.; Polavarapu, P. L. Evidence for Covalent Binding between Copper Ions and Cyclodextrin Cavity: A Vibrational Circular Dichroism Study. Carbohydr. Res. 2000, 323, 63−72. (152) Matsui, Y.; Kinugawa, K. Spectrophotometric and Polarimetric Investigations on Complex Formation between Copper(II) and Cyclodextrins in an Alkaline Solution. Bull. Chem. Soc. Jpn. 1985, 58, 2981−2986. (153) Norkus, E.; Grincien, G.; Vuorinen, T.; Butkus, E.; Vaitkus, R. Stability of a Dinuclear Cu(II)−β-Cyclodextrin Complex. Supramol. Chem. 2003, 15, 425−431. (154) Velasco, M.; Krapacher, C.; de Rossi, R.; Rossi, L. I. Structure Characterization of the Non-Crystalline Complexes of Copper Salts with Native Cyclodextrins. Dalton. Trans. 2016, 45, 10696−10707.

(118) Harada, A.; Takahashi, S. Preparation and Properties of Inclusion Compounds of Transition Metal Complexes of Cyclo-Octa1,5-Diene and Norbornadiene with Cyclodextrins. J. Chem. Soc., Chem. Commun. 1986, 100, 1229. (119) Harada, A.; Yamamoto, S.; Takahashi, S. Preparation and Properties of Inclusion Compounds of Transition-Metal Complexes of Cycloocta-1,5-Diene and Norbornadiene with Cyclodextrins. Organometallics 1989, 8, 2560−2563. (120) Lewis, L. N.; Sumpter, C. A. Cyclodextrin Modification of the Hydrosilylation Reaction. J. Mol. Catal. A: Chem. 1996, 104, 293−297. (121) Six, N.; Guerriero, A.; Landy, D.; Peruzzini, M.; Gonsalvi, L.; Hapiot, F.; Monflier, E. Supramolecularly Controlled Surface Activity of an Amphiphilic Ligand. Application to Aqueous Biphasic Hydroformylation of Higher Olefins. Catal. Sci. Technol. 2011, 1, 1347−1353. (122) Qi, M.; Tan, P. Z.; Xue, F.; Malhi, H. S.; Zhang, Z.-X.; Young, D. J.; Hor, T. S. A. A Supramolecular Recyclable Catalyst for Aqueous Suzuki−Miyaura Coupling. RSC Adv. 2015, 5, 3590−3596. (123) Farras, P.; Waller, H.; Benniston, A. C. Enhanced Photostability of a Ruthenium(II) Polypyridyl Complex under Highly Oxidizing Aqueous Conditions by Its Partial Inclusion into a Cyclodextrin. Chem. - Eur. J. 2016, 22, 1133−1140. (124) Cousin, K.; Menuel, S.; Monflier, E.; Hapiot, F. Hydroformylation of Alkenes in a Planetary Ball Mill: From AdditiveControlled Reactivity to Supramolecular Control of Regioselectivity. Angew. Chem., Int. Ed. 2017, 56, 10564−10568. (125) Anconi, C. P. A.; da Silva Delgado, L.; Alves dos Reis, J. B.; De Almeida, W. B.; Costa, L. A. S.; Dos Santos, H. F. Inclusion Complexes of α-Cyclodextrin and the Cisplatin Analogues Oxaliplatin, Carboplatin and Nedaplatin: A Theoretical Approach. Chem. Phys. Lett. 2011, 515, 127−131. (126) Ravera, M.; Gabano, E.; Bianco, S.; Ermondi, G.; Caron, G.; Vallaro, M.; Pelosi, G.; Zanellato, I.; Bonarrigo, I.; Cassino, C.; et al. Host−guest Inclusion Systems of Pt(IV)-Bis(benzoato) Anticancer Drug Candidates and Cyclodextrins. Inorg. Chim. Acta 2015, 432, 115−127. (127) Shi, Y.; Dabrowiak, J. C. Host−Guest Interactions Involving Platinum Anticancer Agents. DNA Binding and Cytotoxicity of a βCyclodextrin-Adamantane-Pt(IV) Complex. Inorg. Chim. Acta 2012, 393, 337−339. (128) Kahwajy, N.; Nematollahi, A.; Kim, R. R.; Church, W. B.; Wheate, N. J. Comparative Macrocycle Binding of the Anticancer Drug Phenanthriplatin by Cucurbit[n]urils, β-Cyclodextrin and Parasulfonatocalix[4]arene: A 1H NMR and Molecular Modelling Study. J. Inclusion Phenom. Macrocyclic Chem. 2017, 87, 251−258. (129) Braga, S. S.; Marques, J.; Fernandes, J. A.; Paz, F. A. A.; Marques, M. P. M.; Santos, T. M.; Silva, A. M. S. Supramolecular Adducts of Native and Permethylated β-Cyclodextrins with (2,2′dipyridylamine)chlorido(1,4,7-trithiacyclononane)ruthenium(II) Chloride: Solid-State and Biological Activity Studies. Chem. Pap. 2017, 71, 1235−1248. (130) Alston, D. R.; Lilley, T. H.; Stoddart, J. F. The Binding of Cyclobutane-1,1-Dicarboxylatodiamineplatinum(II) by α-Cyclodextrin in Aqueous Solution. J. Chem. Soc., Chem. Commun. 1985, 71, 1600− 1602. (131) Alston, D. R.; Slawin, A. M. Z.; Stoddart, J. F.; Williams, D. J. The X-Ray Crystal Structure of a 1:1 Adduct between α-Cyclodextrin and Cyclobutane-1,1-Dicarboxylatodiammineplationum(II). J. Chem. Soc., Chem. Commun. 1985, 71, 1602−1604. (132) Raynal, M.; Ballester, P.; Vidal-Ferran, A.; van Leeuwen, P. W. N. M. Supramolecular Catalysis. Part 1: Non-Covalent Interactions as a Tool for Building and Modifying Homogeneous Catalysts. Chem. Soc. Rev. 2014, 43, 1660−1733. (133) Liu, Z.; Frasconi, M.; Lei, J.; Brown, Z. J.; Zhu, Z.; Cao, D.; Iehl, J.; Liu, G.; Fahrenbach, A. C.; Botros, Y. Y.; Farha, O. K.; Hupp, J. T.; Mirkin, C. A.; Stoddart, J. F. Selective Isolation of Gold Facilitated by Second-Sphere Coordination with α-Cyclodextrin. Nat. Commun. 2013, 4, 1855. (134) Liu, Z.; Samanta, A.; Lei, J.; Sun, J.; Wang, Y.; Stoddart, J. F. Cation-Dependent Gold Recovery with α-Cyclodextrin Facilitated by 13496


Chemical Reviews

Review

(155) Norkus, E.; Grinciene, G.; Vaitkus, R. Interaction of Lead(II) with β-Cyclodextrin in Alkaline Solutions. Carbohydr. Res. 2002, 337, 1657−1661. (156) Fatin-Rouge, N.; Bünzli, J.-C. G. Thermodynamic and Structural Study of Inclusion Complexes between Trivalent Lanthanide Ions and Native Cyclodextrins. Inorg. Chim. Acta 1999, 293, 53−60. (157) Nair, B. U.; Dismukes, G. C. Models for the Photosynthetic Water Oxidizing Enzyme. A Binuclear Manganese(III)-β-Cyclodextrin Complex. J. Am. Chem. Soc. 1983, 105, 124−125. (158) McNamara, M.; Russell, N. R. Polynuclear Hydroxy-Bridged Structure in Metallo-β-Cyclodextrin Complexes: A Study of Magnetic Susceptibility Versus Temperature. J. Inclusion Phenom. Mol. Recognit. Chem. 1992, 13, 145−154. (159) Benner, K.; Ihringer, J.; Klüfers, P. Cyclodextrin Bucket Wheels: An Oligosaccharide Assembly Accommodates Metal(IV) Centers. Angew. Chem., Int. Ed. 2006, 45, 5818−5822. (160) Ribeiro, A. C. F.; Lobo, V. M. M.; Valente, A. J. M.; Simões, S. M. N.; Sobral, A. J. F. N.; Ramos, M. L.; Burrows, H. D. Association between Ammonium Monovanadate and β-Cyclodextrin as Seen by NMR and Transport Techniques. Polyhedron 2006, 25, 3581−3587. (161) Chung, J. W.; Kwak, S.-Y. Iron-Induced Cyclodextrin SelfAssembly into Size-Controllable Nanospheres. Langmuir 2010, 26, 2418−2423. (162) Kurokawa, G.; Sekii, M.; Ishida, T.; Nogami, T. Crystal Structure of a Molecular Complex from Native β-Cyclodextrin and Copper(II) Chloride. Supramol. Chem. 2004, 16, 381−384. (163) Nicolis, I.; Coleman, A. W.; Charpin, P.; de Rango, C. A Molecular Composite Containing Organic and Inorganic Components-A Complex from β-Cyclodextrin and Hydrated Magnesium Chloride. Angew. Chem., Int. Ed. Engl. 1995, 34, 2381−2383. (164) Nicolis, I.; Coleman, A. W.; Selkti, M.; Villain, F.; Charpin, P.; de Rango, C. Molecular Composites Based on First-Sphere Coordination of Calcium Ions by a Cyclodextrin. J. Phys. Org. Chem. 2001, 14, 35−37. (165) Li, S.-L.; Lan, Y.-Q.; Ma, J.-F.; Yang, J.; Zhang, M.; Su, Z.-M. Unprecedented Dinuclear Tin Derivative of Deprotonated β-Cyclodextrins. Inorg. Chem. 2008, 47, 2931−2933. (166) Klüfers, P.; Schuhmacher, J. Sixteenfold Deprotonated γCyclodextrin Tori as Anions in a Hexadecanuclear Lead(II) Alkoxide. Angew. Chem., Int. Ed. Engl. 1994, 33, 1863−1865. (167) Wei, Y.; Sun, D.; Yuan, D.; Liu, Y.; Zhao, Y.; Li, X.; Wang, S.; Dou, J.; Wang, X.; Hao, A. Pb(II) Metal−Organic Nanotubes based on Cyclodextrins: Biphasic Synthesis, Structures and Properties. Chem. Sci. 2012, 3, 2282−2287. (168) Klüfers, P.; Piotrowski, H.; Uhlendorf, J. Homoleptic Cuprates (II) with Multiply Deprotonated α-Cyclodextrin Ligands. Chem. - Eur. J. 1997, 3, 601−608. (169) Bagabas, A. A.; Frasconi, M.; Iehl, J.; Hauser, B.; Farha, O. K.; Hupp, J. T.; Hartlieb, K. J.; Botros, Y. Y.; Stoddart, J. F. γ-Cyclodextrin Cuprate Sandwich-Type Complexes. Inorg. Chem. 2013, 52, 2854− 2861. (170) Geisselmann, A.; Klüfers, P.; Kropfgans, C.; Mayer, P.; Piotrowski, H. Carbohydrate-Metal Interactions Shaped by Supramolecular Assembling. Angew. Chem., Int. Ed. 2005, 44, 924−927. (171) Nedelko, N.; Kornowicz, A.; Justyniak, I.; Aleshkevych, P.; ́ Prochowicz, D.; Krupiński, P.; Dorosh, O.; Slawska-Waniewska, A.; Lewiński, J. Supramolecular Control over Molecular Magnetic Materials: γ-Cyclodextrin-Templated Grid of Cobalt(II) Single-Ion Magnets. Inorg. Chem. 2014, 53, 12870−12876. (172) McKeown, N. B. Nanoporous Molecular Crystals. J. Mater. Chem. 2010, 20, 10588−10597. (173) Zhang, G.; Mastalerz, M. Organic Cage Compounds − From Shape-Persistency to Function. Chem. Soc. Rev. 2014, 43, 1934−1947. (174) Lewiński, J.; Kaczorowski, T.; Prochowicz, D.; Lipińska, T.; Justyniak, I.; Kaszkur, Z.; Lipkowski, J. Cinchona Alkaloid-Metal Complexes: Noncovalent Porous Materials with Unique Gas Separation Properties. Angew. Chem., Int. Ed. 2010, 49, 7035−7039.

(175) Sokołowski, K.; Bury, W.; Fairen-Jimenez, D.; Justyniak, I.; Sołtys, K.; Prochowicz, D.; Yang, S.; Schröder, M.; Lewiński, J. Permanent Porosity Derived from the Self-Assembly of Highly Luminescent Molecular Zinc Carbonate Nanoclusters. Angew. Chem., Int. Ed. 2013, 52, 13414−13418. (176) Janczak, J.; Prochowicz, D.; Lewiński, J.; Fairen-Jimenez, D.; Bereta, T.; Lisowski, J. Trinuclear Cage-Like Zn(II) Macrocyclic Complexes: Enantiomeric Recognition and Gas Adsorption Properties. Chem. - Eur. J. 2016, 22, 598−609. (177) Li, G.; Yu, W.; Ni, J.; Liu, T.; Liu, Y.; Sheng, E.; Cui, Y. SelfAssembly of a Homochiral Nanoscale Metallacycle from a Metallosalen Complex for Enantioselective Separation. Angew. Chem., Int. Ed. 2008, 47, 1245−1249. (178) Kaboudin, B.; Abedi, Y.; Yokomatsu, T. One-pot Synthesis of 1,2,3-Triazoles from Boronic Acids in Water Using Cu(II)−βCyclodextrin Complex as a Nanocatalyst. Org. Biomol. Chem. 2012, 10, 4543−4548. (179) Decottignies, A.; Fihri, A.; Azemar, G.; Djedaini-Pilard, F.; Len, C. Ligandless Suzuki−Miyaura Reaction in Neat Water With or Without Native β-Cyclodextrin as Additive. Catal. Commun. 2013, 32, 101−107. (180) Kaboudin, B.; Abedi, Y.; Yokomatsu, T. CuII−β-Cyclodextrin Complex as a Nanocatalyst for the Homo- and Cross-Coupling of Arylboronic Acids under Ligand- and Base-Free Conditions in Air: Chemoselective Cross-Coupling of Arylboronic Acids in Water. Eur. J. Org. Chem. 2011, 2011, 6656−6662. (181) Kaboudin, B.; Mostafalu, R.; Yokomatsu, T. Fe3O4 Nanoparticle-Supported Cu(II)-β-Cyclodextrin Complex as a Magnetically Recoverable and Reusable Catalyst for the Synthesis of Symmetrical Biaryls and 1,2,3-Triazoles from Aryl Boronic Acids. Green Chem. 2013, 15, 2266−2274. (182) Girish, Y. R.; Sharath Kumar, K. S.; Muddegowda, U.; Lokanath, N. K.; Rangappa, K. S.; Shashikanth, S. ZrO2-Supported Cu(II)−β-Cyclodextrin Complex: Construction of 2,4,5-trisubstituted1,2,3-Triazoles via Azide−Chalcone Oxidative Cycloaddition and PostTriazole Alkylation. RSC Adv. 2014, 4, 55800−55806. (183) Kaboudin, B.; Salemi, H.; Mostafalu, R.; Kazemi, F.; Yokomatsu, T. Pd(II)-β-cyclodextrin complex: Synthesis, Characterization and Efficient Nanocatalyst for the Selective Suzuki-Miyaura Coupling Reaction in Water. J. Organomet. Chem. 2016, 818, 195−199. (184) Han, C.; Luo, J.; Xu, J.; Zhang, Y.; Zhao, Y.; Xu, X.; Kong, L. Enantioseparation of Aromatic α-Hydroxycarboxylic Acids: The application of a Dinuclear Cu2(II)-β-cyclodextrin Complex as a Chiral Selector in High Speed Counter-Current Chromatography Compared with Native β-Cyclodextrin. J. Chromatography A 2015, 1375, 82−91. (185) Xin, X.; Wang, J.; Gong, Ch.; Xu, H.; Wang, R.; Ji, S.; Dong, H.; Meng, Q.; Zhang, L.; Dai, F.; Sun, D. Cyclodextrin-Based MetalOrganic Nanotube as Fluorescent Probe for Selective Turn-On Detection of Hydrogen Sulfide in Living Cells Based on H2S-Involved Coordination Mechanism. Sci. Rep. 2016, 6, 21951. (186) Xin, X.; Dai, F.; Li, F.; Jin, X.; Wang, R.; Sun, D. A Visual Test Paper Based on Pb(II) Metal−Organic Nanotubes Utilized as a H2S Sensor with High Selectivity and Sensitivity. Anal. Methods 2017, 9, 3094−3098. (187) Ma, H.; Li, X.; Yan, T.; Li, Y.; Liu, H.; Zhang, Y.; Wu, D.; Du, B.; Wei, Q. Sensitive Insulin Detection based on Electrogenerated Chemiluminescence Resonance Energy Transfer between Ru(bpy)32+ and Au Nanoparticle-Doped β-Cyclodextrin-Pb (II) Metal−Organic Framework. ACS Appl. Mater. Interfaces 2016, 8, 10121−10127. (188) Craig, G. A.; Murrie, M. 3d Single-Ion Magnets. Chem. Soc. Rev. 2015, 44, 2135−2147. (189) McNamara, M.; Russell, N. R. Polynuclear Hydroxy-Bridged Structure in Metallo-β-Cyclodextrin Complexes: A Study of Magnetic Susceptibility versus Temperature. J. Inclusion Phenom. Mol. Recognit. Chem. 1992, 13, 145−154. (190) Hoshino, N.; Nakano, M.; Nojiri, H.; Wernsdorfer, W.; Oshio, H. Templating Odd Numbered Magnetic Rings: Oxovanadium Heptagons Sandwiched by β-Cyclodextrins. J. Am. Chem. Soc. 2009, 131, 15100−15101. 13497


Chemical Reviews

Review

Ibuprofen in CD-MOF and Related Bioavailability Studies. Mol. Pharmaceutics 2017, 14, 1831−1839. (211) Li, H.; Hill, M. R.; Huang, R.; Doblin, C.; Lim, S.; Hill, A. J.; Babarao, R.; Falcaro, P. Facile Stabilization of Cyclodextrin Metal− Organic Frameworks under Aqueous Conditions via the Incorporation of C60 in their Matrices. Chem. Commun. 2016, 52, 5973−5976. (212) Singh, V.; Guo, T.; Xu, H.; Wu, L.; Gu, J.; Wu, C.; Gref, R.; Zhang, J. Moisture Resistant and Biofriendly CD-MOF Nanoparticles Obtained via Cholesterol Shielding. Chem. Commun. 2017, 53, 9246− 9249. (213) Furukawa, Y.; Ishiwata, T.; Sugikawa, K.; Kokado, K.; Sada, K. Nano- and Microsized Cubic Gel Particles from Cyclodextrin MetalOrganic Frameworks. Angew. Chem., Int. Ed. 2012, 51, 10566−10569. (214) Gassensmith, J. J.; Furukawa, H.; Smaldone, R. A.; Forgan, R. S.; Botros, Y. Y.; Yaghi, O. M.; Stoddart, J. F. Strong and Reversible Binding of Carbon Dioxide in a Green Metal−Organic Framework. J. Am. Chem. Soc. 2011, 133, 15312−15315. (215) Gassensmith, J. J.; Kim, J. Y.; Holcroft, J. M.; Farha, O. K.; Stoddart, J. F.; Hupp, J. T.; Jeong, N. Ch. A Metal−Organic Framework-Based Material for Electrochemical Sensing of Carbon Dioxide. J. Am. Chem. Soc. 2014, 136, 8277−8282. (216) Holcroft, J. M.; Hartlieb, K. J.; Moghadam, P. Z.; Bell, J. G.; Barin, G.; Ferris, D. P.; Bloch, E. D.; Algaradah, M. M.; Nassar, M. S.; Botros, Y. Y.; Thomas, K. M.; Long, J. R.; Snurr, R. Q.; Stoddart, J. F. Carbohydrate-Mediated Purification of Petrochemicals. J. Am. Chem. Soc. 2015, 137, 5706−5719. (217) Hartlieb, K. J.; Holcroft, J. M.; Moghadam, P. Z.; Vermeulen, N. A.; Algaradah, M. M.; Nassar, M. S.; Botros, Y. Y.; Snurr, R. Q.; Stoddart, J. F. CD-MOF: A Versatile Separation Medium. J. Am. Chem. Soc. 2016, 138, 2292−2301. (218) Han, S.; Wei, Y.; Valente, C.; Forgan, R. S.; Gassensmith, J. J.; Smaldone, R. A.; Nakanishi, H.; Coskun, A.; Stoddart, J. F.; Grzybowski, B. A. Imprinting Chemical and Responsive Micropatterns into Metal-Organic Frameworks. Angew. Chem., Int. Ed. 2011, 50, 276−279. (219) Yang, C.-X.; Zheng, Y.-Z.; Yan, X.-P. γ-Cyclodextrin Metal− Organic Framework for Efficient Separation of Chiral Aromatic Alcohols. RSC Adv. 2017, 7, 36297−36301. (220) Moon, H. R.; Lim, D.-W.; Suh, M. P. Fabrication of Metal Nanoparticles in Metal−Organic Frameworks. Chem. Soc. Rev. 2013, 42, 1807−1824. (221) Wei, Y.; Han, S.; Walker, D. A.; Fuller, P. E.; Grzybowski, B. A. Nanoparticle Core/Shell Architectures within MOF Crystals Synthesized by Reaction Diffusion. Angew. Chem., Int. Ed. 2012, 51, 7435− 7439. (222) Han, S.; Warren, S. C.; Yoon, S. M.; Malliakas, C. D.; Hou, X.; Wei, Y.; Kanatzidis, M. G.; Grzybowski, B. A. Tunneling Electrical Connection to the Interior of Metal−Organic Frameworks. J. Am. Chem. Soc. 2015, 137, 8169−8175. (223) Han, S.; Wei, Y.; Grzybowski, B. A. A Metal-Organic Framework Stabilizes an Occluded Photocatalyst. Chem. - Eur. J. 2013, 19, 11194−11198. (224) Yoon, S. M.; Warren, S. C.; Grzybowski, B. A. Storage of Electrical Information in Metal−Organic-Framework Memristors. Angew. Chem. 2014, 126, 4526−4530. (225) Ma, Z.; Moulton, B. Recent Advances of Discrete Coordination Complexes and Coordination Polymers in Drug Delivery. Coord. Chem. Rev. 2011, 255, 1623−1641. (226) Horcajada, P.; Gref, R.; Baati, T.; Allan, P. K.; Maurin, G.; Couvreur, P.; Ferey, G.; Morris, R. E.; Serre, C. Metal−Organic Frameworks in Biomedicine. Chem. Rev. 2012, 112, 1232−1268. (227) Bernini, M. C.; Fairen-Jimenez, D.; Pasinetti, M.; RamirezPastor, A. J.; Snurr, R. Q. Screening of Bio-Compatible Metal−Organic Frameworks as Potential Drug Carriers using Monte Carlo Simulations. J. Mater. Chem. B 2014, 2, 766−774. (228) Li, H.; Lv, N.; Li, X.; Liu, B.; Feng, J.; Ren, X.; Guo, T.; Chen, D.; Stoddart, J. F.; Gref, R.; Zhang, J. Composite CD-MOF Nanocrystals-Containing Microspheres for Sustained Drug Delivery. Nanoscale 2017, 9, 7454−7463.

(191) Jiang, H.-L.; Xu, Q. Porous Metal−Organic Frameworks as Platforms for Functional Applications. Chem. Commun. 2011, 47, 3351−3370. (192) Suh, M. P.; Park, H. J.; Prasad, T. K.; Lim, D.-W. Hydrogen Storage in Metal−Organic Frameworks. Chem. Rev. 2012, 112, 782− 835. (193) Falcaro, P.; Ricco, R.; Doherty, C. M.; Liang, K.; Hill, A. J.; Styles, M. J. MOF Positioning Technology and Device Fabrication. Chem. Soc. Rev. 2014, 43, 5513−5560. (194) Lu, W.; Wei, Z.; Gu, Z.-Y.; Liu, T.-F.; Park, J.; Park, J.; Tian, J.; Zhang, M.; Zhang, Q.; Gentle, T., III; Bosch, M.; Zhou, H.-C. Tuning the Structure and Function of Metal−Organic Frameworks via Linker Design. Chem. Soc. Rev. 2014, 43, 5561−5593. (195) Silva, P.; Vilela, S. M. F.; Tomé, J. P. C.; Almeida Paz, F. A. Multifunctional Metal−Organic Frameworks: From Academia to Industrial Applications. Chem. Soc. Rev. 2015, 44, 6774−6803. (196) Schoedel, A.; Li, M.; Li, D.; O’Keeffe, M.; Yaghi, O. M. Structures of Metal−Organic Frameworks with Rod Secondary Building Units. Chem. Rev. 2016, 116, 12466−12535. (197) Huang, Y.-B.; Liang, J.; Wang, X.-S.; Cao, R. Multifunctional Metal−Organic Framework Catalysts: Synergistic Catalysis and Tandem Reactions. Chem. Soc. Rev. 2017, 46, 126−157. (198) Kitagawa, S.; Kitaura, R.; Noro, S.-i. Functional Porous Coordination Polymers. Angew. Chem., Int. Ed. 2004, 43, 2334−2375. (199) Lin, Z.-J.; Lu, J.; Hong, M.; Cao, R. Metal−Organic Frameworks based on Flexible Ligands (FL-MOFs): Structures and Applications. Chem. Soc. Rev. 2014, 43, 5867−5895. (200) Cook, T. R.; Zheng, Y.-R.; Stang, P. J. Metal−Organic Frameworks and Self-Assembled Supramolecular Coordination Complexes: Comparing and Contrasting the Design, Synthesis, and Functionality of Metal−Organic Materials. Chem. Rev. 2013, 113, 734−777. (201) Smaldone, R. A.; Forgan, R. S.; Furukawa, H.; Gassensmith, J. J.; Slawin, A. M. Z.; Yaghi, O. M.; Stoddart, J. F. Metal-Organic Frameworks from Edible Natural Products. Angew. Chem., Int. Ed. 2010, 49, 8630−8634. (202) Forgan, R. S.; Smaldone, R. A.; Gassensmith, J. J.; Furukawa, H.; Cordes, D. B.; Li, Q.; Wilmer, C. E.; Botros, Y. Y.; Snurr, R. Q.; Slawin, A. M. Z.; Stoddart, J. F. Nanoporous Carbohydrate Metal− Organic Frameworks. J. Am. Chem. Soc. 2012, 134, 406−417. (203) Patel, H. A.; Islamoglu, T.; Liu, Z.; Nalluri, S. K. M.; Samanta, A.; Anamimoghadam, O.; Malliakas, C. D.; Farha, O. K.; Stoddart, J. F. Noninvasive Substitution of K+ Sites in Cyclodextrin Metal−Organic Frameworks by Li+ Ions. J. Am. Chem. Soc. 2017, 139, 11020−11023. (204) Hartlieb, K. J.; Peters, A. W.; Wang, T. C.; Deria, P.; Farha, O. K.; Hupp, J. T.; Stoddart, J. F. Functionalised Cyclodextrin-Based Metal-Organic Frameworks. Chem. Commun. 2017, 53, 7561−7564. (205) Gassensmith, J. J.; Smaldone, R. A.; Forgan, R. S.; Wilmer, C. E.; Cordes, D. B.; Botros, Y. Y.; Slawin, A. M. Z.; Snurr, R. Q.; Stoddart, J. F. Polyporous Metal-Coordination Frameworks. Org. Lett. 2012, 14, 1460−1463. (206) Lu, H.; Yang, X.; Li, S.; Zhang, Y.; Sha, J.; Li, C.; Sun, J. Study on a New Cyclodextrin based Metal−Organic Framework with Chiral Helices. Inorg. Chem. Commun. 2015, 61, 48−52. (207) Sha, J.-Q.; Wu, L.-H.; Li, S.-X.; Yang, X.-N.; Zhang, Y.; Zhang, Q.-N.; Zhu, P.-P. Synthesis and Structure of New Carbohydrate Metal−Organic Frameworks and Inclusion Complexes. J. Mol. Struct. 2015, 1101, 14−20. (208) Liu, J.; Bao, T.-Y.; Yang, X.-Y.; Zhu, P.-P.; Wu, L.-H.; Sha, J.Q.; Zhang, L.; Dong, L.-Z.; Cao, X.-L.; Lan, Y.-Q. Controllable Porosity Conversion of Metal-Organic Frameworks Composed of Natural Ingredients for Drug Delivery. Chem. Commun. 2017, 53, 7804−7807. (209) Xu, H.; Rodríguez-Hermida, S.; Pérez-Carvajal, P.; Juanhuix, J.; Imaz, I.; Maspoch, D. A First Cyclodextrin-Transition Metal Coordination Polymer. Cryst. Growth Des. 2016, 16, 5598−5602. (210) Hartlieb, K. J.; Ferris, D. P.; Holcroft, J. M.; Kandela, I.; Stern, C. L.; Nassar, M. S.; Botros, Y. Y.; Stoddart, J. F. Encapsulation of 13498


Chemical Reviews

Review

Sensitive Fluorescent Detection of Dopamine. Sens. Actuators, B 2018, 254, 1017−1024. (249) Kochkar, H.; Aouine, M.; Ghorbel, A.; Berhault, G. ShapeControlled Synthesis of Silver and Palladium Nanoparticles using βCyclodextrin. J. Phys. Chem. C 2011, 115, 11364−11373. (250) Joseph, D.; Geckeler, K. E. Surfactant-Directed Multiple Anisotropic Gold Nanostructures: Synthesis and Surface-Enhanced Raman Scattering. Langmuir 2009, 25, 13224−13231. (251) Huang, T.; Meng, F.; Qi, L. Controlled Synthesis of Dendritic Gold Nanostructures Assisted by Supramolecular Complexes of Surfactant with Cyclodextrin. Langmuir 2010, 26, 7582−7589. (252) Jia, H.; Schmitz, D.; Ott, A.; Pich, A.; Lu, Y. Cyclodextrin Modified Microgels as ″Nanoreactor″ for the Generation of Au Nanoparticles with Enhanced Catalytic Activity. J. Mater. Chem. A 2015, 3, 6187−6195. (253) Amiens, C.; Ciuculescu-Pradines, D.; Philippot, K. Controlled Metal Nanostructures: Fertile Ground for Coordination Chemists. Coord. Chem. Rev. 2016, 308, 409−432. (254) Wang, D.; Astruc, D. The Recent Development of Efficient Earth-Abundant Transition-Metal Nanocatalysts. Chem. Soc. Rev. 2017, 46, 816−854. (255) Hapiot, F.; Ponchel, A.; Tilloy, S.; Monflier, E. Cyclodextrins and Their Applications in Aqueous-Phase Metal-Catalyzed Reactions. C. R. Chim. 2011, 14, 149−166. (256) Denicourt-Nowicki, A.; Roucoux, A. Noble Metal Nanoparticles Stabilized by Cyclodextrins: A Pertinent Partnership for Catalytic Applications. Curr. Org. Chem. 2010, 14, 1266−1283. (257) Xue, C.; Palaniappan, K.; Arumugam, G.; Hackney, S. A.; Liu, J.; Liu, H. Y. Sonogashira Reactions Catalyzed by Water-Soluble, βCyclodextrin-Capped Palladium Nanoparticles. Catal. Lett. 2007, 116, 94−100. (258) Zhao, X.; Liu, X.; Lu, M. β-cyclodextrin-Capped Palladium Nanoparticle-Catalyzed Ligand-Free Suzuki and Heck Couplings in Low-Melting β-Cyclodextrin/NMU Mixtures. Appl. Organomet. Chem. 2014, 28, 635−640. (259) Léger, B.; Menuel, S.; Ponchel, A.; Hapiot, F.; Monflier, E. Nanoparticle-Based Catalysis using Supramolecular Hydrogels. Adv. Synth. Catal. 2012, 354, 1269−1272. (260) Denicourt-Nowicki, A.; Ponchel, A.; Monflier, E.; Roucoux, A. Methylated Cyclodextrins: An Efficient Protective Agent in Water for Zerovalent Ruthenium Nanoparticles and a Supramolecular Shuttle in Alkene and Arene Hydrogenation Reactions. Dalton Trans. 2007, 5714−5719. (261) Wang, M.; Wang, J.; Wang, Y.; Liu, C.; Liu, J.; Qiu, Z.; Xu, Y.; Lincoln, S. F.; Guo, X. Synergetic Catalytic Effect of α-cyclodextrin on Silver Nanoparticles Loaded in Thermosensitive Hydrogel. Colloid Polym. Sci. 2016, 294, 1087−1095. (262) Stiles, P. L.; Dieringer, J. A.; Shah, N. C.; Van Duyne, R. P. Surface-Enhanced Raman Spectroscopy. Annu. Rev. Anal. Chem. 2008, 1, 601−626. (263) Huang, T.; Meng, F.; Qi, L. Facile Synthesis and OneDimensional Assembly of Cyclodextrin-Capped Gold Nanoparticles and their Applications in Catalysis and Surface-Enhanced Raman Scattering. J. Phys. Chem. C 2009, 113, 13636−13642. (264) Prasad, P. N. Nanophotonics; Wiley-Interscience: New York, 2004. (265) Somers, R. C.; Bawendi, M. G.; Nocera, D. G. CdSe Nanocrystal based Chem-/Bio- Sensors. Chem. Soc. Rev. 2007, 36, 579−591. (266) Ling, D.; Hackett, M. J.; Hyeon, T. Surface Ligands in Synthesis, Modification, Assembly and Biomedical Applications of Nanoparticles. Nano Today 2014, 9, 457−477. (267) Boles, M. A.; Ling, D.; Hyeon, T.; Talapin, D. V. The Surface Science of Nanocrystals. Nat. Mater. 2016, 15, 141−153. (268) Gui, H. R.; Jin, H.; Wang, Z.; Tan, L. Recent Advances in Synthetic Methods and Applications of Colloidal Silver Chalcogenide Quantum Dots. Coord. Chem. Rev. 2015, 296, 91−124.

(229) Hervés, P.; Pérez-Lorenzo, M.; Liz-Márzan, L. M.; Dzubiella, J.; Lu, Y.; Ballauff, M. Catalysis by Metallic Nanoparticles in Aqueous Solution: Model Reactions. Chem. Soc. Rev. 2012, 41, 5577−5587. (230) Taladriz-Blanco, P.; Hervés, J.; Pérez-Juste, J. Supported Pd Nanoparticles for Carbon−Carbon Coupling Reactions. Top. Catal. 2013, 56, 1154−1170. (231) Doria, G.; Conde, J.; Veigas, B.; Giestas, L.; Almeida, C.; Assunçaõ , M.; Rosa, J.; Baptista, P. V. Noble Metal Nanoparticles for Biosensing Applications. Sensors 2012, 12, 1657−1687. (232) Dreaden, E. C.; Alkilany, A. M.; Huang, X.; Murphy, C. J.; ElSayed, M. A. The Golden Age: Gold Nanoparticles for Biomedicine. Chem. Soc. Rev. 2012, 41, 2740−2779. (233) Alvarez, J.; Liu, J.; Román, E.; Kaifer, A. E. Water-Soluble Platinum and Palladium Nanoparticles Modified with Thiolated βCyclodextrin. Chem. Commun. 2000, 1151−1152. (234) Liu, Z.; Jiang, M. Reversible Aggregation of Gold Nanoparticles Driven by Inclusion Complexation. J. Mater. Chem. 2007, 17, 4249−4254. (235) Komiyama, M.; Hirai, H. Colloidal Rhodium Dispersions Protected by Cyclodextrins. Bull. Chem. Soc. Jpn. 1983, 56, 2833− 2834. (236) Liu, Y.; Male, K. B.; Bouvrette, P.; Luong, J. H. T. Control of the Size and Distribution of Gold Nanoparticles by Unmodified Cyclodextrins. Chem. Mater. 2003, 15, 4172−4180. (237) Sylvestre, J.-P.; Kabashin, A. V.; Sacher, E.; Meunier, M.; Luong, J. H. T. Stabilization and Size Control of Gold Nanoparticles during Laser Ablation in Aqueous Cyclodextrins. J. Am. Chem. Soc. 2004, 126, 7176−7177. (238) Aswathy, B.; Avadhani, G. S.; Suji, S.; Sony, G. Synthesis of βCyclodextrin Functionalized Gold Nanoparticles for the Selective Detection of Pb2+ Ions from Aqueous Solution. Front. Mater. Sci. 2012, 6, 168−175. (239) Menuel, S.; Léger, B.; Addad, A.; Monflier, E.; Hapiot, F. Cyclodextrins as Effective Additives in AuNPs-Catalyzed Reduction of Nitrobenzene Derivatives in a Ball-Mill. Green Chem. 2016, 18, 5500− 5509. (240) Ng, C. H. B.; Yang, J.; Fan, W. Y. Synthesis and Self-Assembly of One-Dimensional Sub-10 nm Ag Nanoparticles with Cyclodextrin. J. Phys. Chem. C 2008, 112, 4141−4145. (241) Amiri, S.; Duroux, L.; Larsen, K. L. Silver Nanoparticle Colloids with γ-Cyclodextrin: Enhanced Stability and Gibbs− Marangoni Flow. J. Nanopart. Res. 2015, 17, 21. (242) Giuffrida, S.; Ventimiglia, G.; Petralia, S.; Conoci, S.; Sortino, S. Facile Light-Triggered One-Step Synthesis of Small and Stable Platinum Nanoparticles in an Aqueous Medium from a β-Cyclodextrin Host−Guest Inclusion Complex. Inorg. Chem. 2006, 45, 508−510. (243) Ventimiglia, G.; Motta, A. A Facile and Green Synthesis of Small Silver Nanoparticles in β-Cyclodextrins Performing as Chemical Microreactors and Capping Agents. Sens. Transducers J. 2012, 146, 59− 68. (244) Mori, K.; Yoshioka, N.; Kondo, Y.; Takeuchi, T.; Yamashita, H. Catalytically Active, Magnetically Separable, and Water-Soluble FePt Nanoparticles Modified with Cyclodextrin for Aqueous Hydrogenation Reactions. Green Chem. 2009, 11, 1337−1342. (245) Zhao, Y.; Zhu, H.; Zhu, Q.; Huang, Y.; Xia, Y. Three-in-One: Sensing, Self-Assembly, and Cascade Catalysis of Cyclodextrin Modified Gold Nanoparticles. J. Am. Chem. Soc. 2016, 138, 16645− 16654. (246) Pande, S.; Ghosh, K.; Praharaj, S.; Panigrahi, S.; Basu, S.; Jana, S.; Pal, A.; Tsukuda, T.; Pal, T. Synthesis of Normal and Inverted Gold−Silver Core−Shell Architectures in β-Cyclodextrin and their Applications in SERS. J. Phys. Chem. C 2007, 111, 10806−10813. (247) Premkumar, T.; Geckeler, K. E. Facile Synthesis of Silver Nanoparticles using Unmodified Cyclodextrin and their SurfaceEnhanced Raman Scattering Activity. New J. Chem. 2014, 38, 2847− 2855. (248) Halawa, M. I.; Wu, F.; Fereja, T. H.; Lou, B.; Xu, G. One-pot Green Synthesis of Supramolecular β-Cyclodextrin Functionalized Gold Nanoclusters and Their Application for Highly Selective and 13499


Chemical Reviews

Review

(290) Zhang, X.; Yang, Z.; Li, X.; Deng, N.; Qian, S. β-Cyclodextrin’s Orientation onto TiO 2 and Its Paradoxical Role in Guest’s Photodegradation. Chem. Commun. 2013, 49, 825−827. (291) Lu, P.; Wu, F.; Deng, N. Enhancement of TiO2 Photocatalytic Redox Ability by β-Cyclodextrin in Suspended Solutions. Appl. Catal., B 2004, 53, 87−93. (292) Attarchi, N.; Montazer, M.; Toliyat, T. Ag/TiO2/β-CD Nanocomposite: Preparation and Photo Catalytic Properties for Methylene Blue Degradation. Appl. Catal., A 2013, 467, 107−116. (293) Rajalakshmi, S.; Pitchaimuthu, S.; Kannan, N.; Velusamy, P. Enhanced Photocatalytic Activity of Metal Oxides/β-Cyclodextrin Nanocomposites for Decoloration of Rhodamine B Dye Under Solar Light Irradiation. Appl. Water Sci. 2017, 7, 115−127. (294) Krupiński, P.; Kornowicz, A.; Sokołowski, K.; Cieślak, A. M.; Lewiński, J. Applying Mechanochemistry for Bottom-Up Synthesis and Host-Guest Surface Modification of Semiconducting Nanocrystals: A Case of Water-Soluble β-Cyclodextrin-Coated Zinc Oxide. Chem. Eur. J. 2016, 22, 7817−7823. (295) Lim, S. Y.; Shen, W.; Gao, Z. Carbon Quantum Dots and Their Applications. Chem. Soc. Rev. 2015, 44, 362−381. (296) Zhou, S.; Xu, H.; Gan, W.; Yuan, Q. Graphene Quantum Dots: Recent Progress in Preparation and Fluorescence Sensing Applications. RSC Adv. 2016, 6, 110775−110788. (297) Mondal, S.; Purkayastha, P. α-Cyclodextrin Functionalized Carbon Dots: Pronounced Photoinduced Electron Transfer by Aggregated Nanostructures. J. Phys. Chem. C 2016, 120, 14365− 14371. (298) Xiao, Q.; Lu, S.; Huang, C.; Su, W.; Huang, S. Novel N-Doped Carbon Dots/β-Cyclodextrin Nanocomposites for Enantioselective Recognition of Tryptophan Enantiomers. Sensors 2016, 16, 1874. (299) Ou, J.; Zhu, Y.; Kong, Y.; Ma, J. Graphene Quantum Dots/βCyclodextrin Nanocomposites: A Novel Electrochemical Chiral Interface for Tryptophan Isomer Recognition. Electrochem. Commun. 2015, 60, 60−63. (300) Shadjou, N.; Hasanzadeh, M.; Talebi, F.; Marjani, A. P. Integration of β-Cyclodextrin into Graphene Quantum Dot NanoStructure and its Application towards Detection of Vitamin C at Physiological pH: A New Electrochemical Approach. Mater. Sci. Eng., C 2016, 67, 666−674. (301) Wei, M.; Tian, D.; Liu, S.; Zheng, X.; Duan, S.; Zhou, C. βCyclodextrin Functionalized Graphene Material: A Novel Electrochemical Sensor for Simultaneous Determination of 2-chlorophenol and 3-chlorophenol. Sens. Actuators, B 2014, 195, 452−458. (302) Hasanzadeh, M.; Shadjou, N.; Marandi, M. Graphene Quantum Dot Functionalized by Chitosan and Beta-Cyclodextrin as a New Support Nanocomposite Material for Efficient Methanol Electrooxidation. J. Alloys Compd. 2016, 688, 171−186. (303) Hasanzadeh, M.; Shadjou, N.; Marandi, M. Graphene Quantum Dots Functionalized by Chitosan and β-Cyclodextrin: An Advanced Nanocomposite for Sensing of Multi-Analytes at Physiological pH. J. Nanosci. Nanotechnol. 2017, 17, 4598−4607. (304) Zhan, F.; Gao, F.; Wang, X.; Xie, L.; Gao, F.; Wang, Q. Determination of Lead(II) by Adsorptive Stripping Voltammetry Using a Glassy Carbon Electrode Modified with β-Cyclodextrin and Chemically Reduced Graphene Oxide Composite. Microchim. Acta 2016, 183, 1169−1176. (305) Li, Z.; Zhang, L.; Huang, X.; Ye, L.; Lin, S. Shape-Controlled Synthesis of Pt Nanoparticles via Integration of Graphene and βCyclodextrin and Using as a Novel Electrocatalyst for Methanol Oxidation. Electrochim. Acta 2014, 121, 215−222. (306) Bonacchi, D.; Caneschi, A.; Dorignac, D.; Falqui, A.; Gatteschi, D.; Rovai, D.; Sangregorio, C.; Sessoli, R. Nanosized Iron Oxide Particles Entrapped in Pseudo-Single Crystals of γ-Cyclodextrin. Chem. Mater. 2004, 16, 2016−2020. (307) Feng, M.; Lu, Y.; Yang, Y.; Zhang, M.; Xu, Y.-J.; Gao, H.-L.; Dong, L.; Xu, W.-P.; Yu, S.-H. Bioinspired Greigite Magnetic Nanocrystals: Chemical Synthesis and Biomedicine Applications. Sci. Rep. 2013, 3, 2994.

(269) Medintz, I. L.; Uyeda, H. T.; Goldman, E. R.; Mattoussi, H. Quantum Dot Bioconjugates for Imaging, Labelling and Sensing. Nat. Mater. 2005, 4, 435−446. (270) Zhou, J.; Yang, Y.; Zhang, C.-Y. Toward Biocompatible Semiconductor Quantum Dots: From Biosynthesis and Bioconjugation to Biomedical Application. Chem. Rev. 2015, 115, 11669−11717. (271) Freeman, R.; Willner, I. Optical Molecular Sensing with Semiconductor Quantum Dots (QDs). Chem. Soc. Rev. 2012, 41, 4067−4085. (272) Yu, W. W.; Chang, E.; Drezek, R.; Colvin, V. L. Water-Soluble Quantum Dots for Biomedical Applications. Biochem. Biophys. Res. Commun. 2006, 348, 781−786. (273) Jing, L.; Kershaw, S. V.; Li, Y.; Huang, X.; Li, Y.; Rogach, A. L.; Gao, M. Aqueous Based Semiconductor Nanocrystals. Chem. Rev. 2016, 116, 10623−10730. (274) Palaniappan, K.; Xue, C. H.; Arumugam, G.; Hackney, S. A.; Liu, J. Water-Soluble, Cyclodextrin-Modified CdSe-CdS Core-Shell Structured Quantum Dots. Chem. Mater. 2006, 18, 1275−1280. (275) Dorokhin, D.; Hsu, S.-H.; Tomczak, N.; Reinhoudt, D. N.; Huskens, J.; Velders, A. H.; Vancso, G. J. Fabrication and Luminescence of Designer Surface Patterns with β-Cyclodextrin Functionalized Quantum Dots via Multivalent Supramolecular Coupling. ACS Nano 2010, 4, 137−142. (276) Palaniappan, K.; Hackney, S. A.; Liu, J. Supramolecular Control of Complexation-Induced Fluorescence Change of Watersoluble, β-cyclodextrin-Modified CdS Quantum Dots. Chem. Commun. 2004, 23, 2704−2705. (277) Li, H.; Han, C. Sonochemical Synthesis of Cyclodextrin-coated Quantum Dots for Optical Detection of Pollutant Phenols in Water. Chem. Mater. 2008, 20, 6053−6059. (278) Dorokhin, D.; Tomczak, N.; Han, M.; Reinhoudt, D. N.; Velders, A. H.; Vancso, G. J. Reversible Phase Transfer of (CdSe/ZnS) Quantum Dots between Organic and Aqueous Solutions. ACS Nano 2009, 3, 661−667. (279) Shang, Z. B.; Hu, S.; Wang, Y.; Jin, W. J. Interaction of βCyclodextrin-Capped CdSe Quantum Dots with Inorganic Anions and Cations. Luminescence 2011, 26, 585−591. (280) Freeman, R.; Finder, T.; Bahshi, L.; Willner, I. β-CyclodextrinModified CdSe/ZnS Quantum Dots for Sensing and Chiroselective Analysis. Nano Lett. 2009, 9, 2073−2076. (281) Durán, G. M.; Abellán, C.; Contento, A. M.; Ríos, A. Discrimination of Penicillamine Enantiomers Using β-Cyclodextrin Modified CdSe/ZnS Quantum Dots. Microchim. Acta 2017, 184, 815− 824. (282) Han, C.; Li, H. Chiral Recognition of Amino Acids Based on Cyclodextrin-Capped Quantum Dots. Small 2008, 4, 1344−1350. (283) Durán, G. M.; Contento, A. M.; Ríos, A. A Continuous Method Incorporating β-Cyclodextrin Modified CdSe/ZnS Quantum Dots for Determination of Ascorbic Acid. Anal. Methods 2015, 7, 3472−3479. (284) Hu, T.; Na, W.; Yan, X.; Su, X. Sensitive Fluorescence Detection of ATP Based on Host-Guest Recognition Between NearInfrared β-Cyclodextrin-CuInS2 QDs and Aptamer. Talanta 2017, 165, 194−200. (285) Feng, J.; Miedaner, A.; Ahrenkiel, P.; Himmel, M. E.; Curtis, C.; Ginley, D. Self-Assembly of Photoactive TiO2−Cyclodextrin Wires. J. Am. Chem. Soc. 2005, 127, 14968−14969. (286) Han, S.; Yoon, S.; Nichols, W. T. Sunlight-Initiated SelfAssembly of Cyclodextrin Networks. Appl. Surf. Sci. 2012, 261, 730− 734. (287) Nichols, W. T.; Yoon, S. Cyclodextrin Directed Self-Assembly of TiO2 Nanoparticles. Appl. Surf. Sci. 2013, 285, 517−523. (288) Lang, X.; Chen, X.; Zhao, J. Heterogeneous Visible Light Photocatalysis for Selective Organic Transformations. Chem. Soc. Rev. 2014, 43, 473−486. (289) Kakroudi, M. A.; Kazemi, F.; Kaboudin, B. β-CyclodextrinTiO2: Green Nest for Reduction of Nitroaromatic Compounds. RSC Adv. 2014, 4, 52762−52769. 13500


Chemical Reviews

Review

(308) Kong, L.; Yan, L.; Qu, Z.; Yan, N.; Li, L. β-Cyclodextrin Stabilized Magnetic Fe3S4 Nanoparticles for Efficient Removal of Pb(II). J. Mater. Chem. A 2015, 3, 15755−15763.

13501


Interactions of Native Cyclodextrins with Metal Ions and Inorganic

Recommend Documents