Three Cadmium Coordination Polymers with Carboxylate and Pyridine

Article pubs.acs.org/IC

Three Cadmium Coordination Polymers with Carboxylate and Pyridine Mixed Ligands: Luminescent Sensors for FeIII and CrVI Ions in an Aqueous Medium Yanna Lin,† Xiaoping Zhang,† Wenjie Chen,† Wei Shi,*,†,‡,§ and Peng Cheng*,†,‡,§ †

College of Chemistry and Key Laboratory of Advanced Energy Materials Chemistry (MOE) and ‡State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China § Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300071, China S Supporting Information *

ABSTRACT: Three new water-stable luminescent Cd(II) coordination polymers (CPs), {[Cd2(bptc)(2,2′-bipy)2(H2O)2]}n (1), {[Cd2(bptc)(phen)2]·4H2O}n (2), and {[Cd2(bptc)(4,4′-bipy)(H2O)2]·4H2O}n (3), were solvothermally synthesized with mixed ligands of 3,3′,5,5′-biphenyltetracarboxylic acid (H4bptc) and Ndonor ligands (2,2′-bipy = 2,2′-bipyridine; phen = 1,10-phenanthroline; 4,4′-bipy = 4,4′-bipyridine). The CPs 1−3 show structural diversity from a 1D ladder chain to a 2D layer to a 3D porous framework, tuned by different ancillary ligands. Topological analyses reveal that the CP 2 is a 4-connected uninodal 2D net with the Schläfli point symbol {44·62}, while the CP 3 displays a 4,6connected 2-nodal 3D net with the point symbol {3·42·52·6}{32·42· 52·64·74·8}. Luminescent property studies reveal that the CPs 1−3 are promising luminescent sensors that can highly select and sensitively detect ferric and chromate/dichromate ions, in which the CP 1 with a 1D structure showed the best performance, free from the interference of other ions present in an aqueous medium. Moreover, the mechanism for the sensing properties was studied in detail.

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INTRODUCTION Fe ions exist widely in human bodies and play important roles in many biological systems with physiological and biochemical processes, such as electron transfer, hemoglobin formation, DNA replication, and cell cycle.1 Its excess or deficiency can not only interfere with cellular homeostasis and metabolism but also lead to serious diseases such as anemia, methemoglobinemia, and Alzheimer’s.2 As a result, highly selective and sensitive detection of Fe3+ ions in an aqueous medium is very essential for human health. On the other hand, Cr2O72−/CrO42− ions, persistent pollutants to ecosystems, are broadly utilized in industries such as leather tanning, electronic product manufacturing, and agriculture.3 Prolonged exposure to Cr2O72−/CrO42− ions can raise the risk of getting lung cancer and cause adverse reactions such as skin allergy.4 Hence, it is urgent to develop fast and facile methods for detecting those metal ions for the benefit of human beings. Coordination polymers (CPs), as a new generation of molecular materials, are constructed by metal ions/clusters and organic ligands via coordination bonds.5 CPs have received significant interest from chemists because of both their fascinating topological structures and functionalities,6 which give them enormous potential in gas storage and separation,7 catalysis,8 magnetism,9 drug delivery,10 and luminescence.11 The luminescent sensing properties of CPs are mainly

dependent on their compositions, structures, and supramolecular interactions with guest species via coordination bonds, hydrogen-bonding and π−π interactions.11c,e,.12 In comparison with other analysis techniques, such as chromatography,13 atomic absorption spectrometry,14 electrochemical methods,15 and inductively coupled plasma optical emission spectroscopy,16 the luminescence-based sensing method, as a new approach, has the advantages of high selectivity, short response time, and easy portability.17 Luminescent sensors for cations,18 anions,19 small molecules,20 biomarkers,21 nitroaromatic explosives,22 and pH23 based on CPs containing lanthanide and d10 metal ions have been well documented recently.11b To date, most of the luminescent CP sensors for Fe3+ and Cr2O72−/CrO42− ions are studied in nonaqueous solvents, which limits the application of those materials in practical applications.24 To build CPs with the desired structures and luminescent properties, organic aromatic polycarboxylate ligands have been widely used because of their multiple bridging and chelating coordination modes.25 The binding of N-donor ligands with polycarboxylate is a good combination to construct novel and stable structures.26 The coordination spheres of central metal

3+

© XXXX American Chemical Society

Received: July 13, 2017

A

DOI: 10.1021/acs.inorgchem.7b01790 Inorg. Chem. XXXX, XXX, XXX−XXX

Article

Inorganic Chemistry Scheme 1. Synthetic Route of the CPs 1−3

atmosphere. UV−vis spectra were obtained on an Agilent Technologies Cary 100 UV−vis spectrophotometer. Luminescent spectra were measured on an Agilent Cary Eclipse fluorescence spectrophotometer at room temperature. X-ray Crystallography. Single-crystal data of the CPs 1−3 were collected on an Agilent Technologies SuperNova single-crystal diffractometer at 120 K equipped with graphite-monochromated Mo Kα radiation (λ = 0.71073 Å). The structures were solved by SHELXS (direct methods) and refined by SHELXL (full matrix least-squares techniques) in the Olex2 package.30 The disordered guest molecules were removed by PLATON/SQUEEZE,31 and the molecular formula were determined by combining single-crystal structures, TGA, and EA. The crystal parameters, data collection, and refinements are summarized in Table S1. Selected bond lengths and angles are listed in Tables S2−S4. Preparation of Samples for Luminescence Measurements. Each milled sample of the CPs 1−3 (3.0 mg) was immersed in 4.0 mL of 1 × 10−3 M aqueous solutions of AgNO3, MClx (M = Li+, Na+, K+, Mg2+, Ca2+, Sr2+, Ba2+, Cr3+, Mn2+, Fe3+, Co2+, Au3+, Zn2+, Cd2+, Hg2+, Al3+, and Pb2+) or NayX (X = F−, Cl−, Br−, I−, H2PO4−, HPO42−, PO43−, CO32−, HCO32−, SO42−, SO32−, NO2−, C2O42−, ClO4−, CrO42−, and Cr2O72−). The uniform suspensions were obtained after ultrasonication for 30 min. Synthesis. Synthesis of {[Cd2(bptc)(2,2′-bipy)2(H2O)2]}n (1). A mixture of Cd(NO3)2·4H2O (0.0308 g, 0.1 mmol), H4bptc (0.0165 g, 0.05 mmol), 2,2′-bipy (0.0156 g, 0.1 mmol), LiOH·H2O (0.0042 g, 0.1 mmol), N,N-dimethylformamide (DMF)/H2O (1:1; 4 mL), and HNO3 (100 μL, 1.6 mmol) was put into a 25 mL Teflon-lined stainless steel vessel, heated at 130 °C for 72 h, and then cooled to room temperature at a rate of 4 °C h−1. Colorless sheetlike crystals were obtained in 78% yield based on Cd(NO3)2·4H2O. Elem anal. Calcd for C36H26N4O10Cd2 (Mr = 899.42): C, 48.07; H, 2.91; N, 6.23. Found: C, 48.01; H, 3.01; N, 6.10. IR data (KBr, cm−1): 3260 (br), 1552 (m), 1352 (m), 1144 (w), 1016 (w), 899 (w), 837 (w), 770 (s), 733 (s), 659 (m), 411 (m) (Figure S1a). Synthesis of {[Cd2(bptc)(phen)2]·4H2O}n (2). The synthesis of 2 was similar to that of 1 except that 2,2′-bipy (0.0156 g, 0.1 mmol), DMF/ H2O (1:1; 4 mL), and HNO3 (100 μL, 1.6 mmol) were replaced by 1,10-phen (0.0180 g, 0.1 mmol), DMF/H2O (1:2; 4.5 mL), and HNO3 (50 μL, 0.8 mmol). Light-green sheetlike crystals were obtain in 67% yield based on Cd(NO3)2·4H2O. Elem anal. Calcd for C40H30N4O12Cd2 (Mr = 983.51): C, 48.85; H, 3.07; N, 5.70. Found: C, 48.71; H, 3.01; N, 5.88. IR data (KBr, cm−1): 3406 (br), 1741 (w), 1665 (w), 1601 (w), 1545 (m), 1407 (m), 1357 (m), 1137 (w), 1082 (w), 850 (m), 774 (m), 726 (s), 662 (m), 418 (m) (Figure S1b).

ions can be protected by the N-donor ligands, which block their interactions with water from the environment and result in high hydrostability.27 However, because of the influence of many factors, it is still quite challenging to predict the structures of mixed-ligand systems.28 In this contribution, we used 3,3′,5,5′biphenyltetracarboxylic acid (H4bptc) as the main ligand, which not only contains a conjugated π-electron system but also possesses four carboxylic groups. The ligand H4bptc can be deprotonated to H3bptc−, H2bptc2−, Hbptc3−, and bptc4−, enriching the monodentate and multidentate coordination modes. By using various N-donor ligands as auxiliary ligands, three new water-stable CPs, {[Cd2(bptc)(2,2′-bipy)2(H2O)2]}n (1), {[Cd2(bptc)(phen)2]·4H2O}n (2), and {[Cd2(bptc)(4,4′bipy)(H2O)2]·4H2O}n (3) (2,2′-bipy = 2,2′-bipyridine; phen = 1,10-phenanthroline; 4,4′-bipy = 4,4′-bipyridine), were obtained under solvothermal conditions. The pH tests and timedependent luminescent studies suggest that the CPs 1−3 have good stability and dispersibility in water. Luminescent studies further show that all of these CPs display a highly sensitive and selective sensing for Fe3+ and Cr2O72−/CrO42− ions via significant fluorescence quenching behavior in an aqueous medium. The Ksv value of the CP 1 with a 1D structure is 8.61 × 103 M−1 for sensing Fe3+ ions and 1.17 × 104/7.95 × 103 M−1 for sensing Cr2O72−/CrO42− ions. The detection limits were calculated to be 2.76 ppm toward Fe3+ ions and 2.17/1.51 ppm toward Cr2O72−/CrO42− ions. To the best of our knowledge, it is rather rare for 1D CPs to be used as luminescent sensors with high sensitivity and low detection limit, as well as a good recycle performance, to detect cations/anions free from the interference of other ions present in an aqueous medium.29

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EXPERIMENTAL SECTION

Materials and Methods. All of the reagents and solvents were commercially available and were used without further purification. Elemental analyses (EA) for C, H, and N were carried out on a PerkinElmer 240 CHN elemental analyzer. Fourier transform infrared (FT-IR) spectra were recorded in the range of 500−4000 cm−1 on a Bruker ALPHA spectrophotometer. Powder X-ray diffraction (PXRD) measurements were carried out on a Rigaku D/Max-2500 X-ray diffractometer using Cu Kα radiation. Thermogravimetric analyses (TGA) were performed on a Labsys NETZSCH TG 209 Setaram apparatus at a heating rate of 10 °C min−1 under a nitrogen B


Article

Inorganic Chemistry Synthesis of {[Cd2(bptc)(4,4′-bipy)(H2O)2]·4H2O}n (3). The preparation of 3 was similar to the synthesis of 1 except that 4,4′-bipy (0.0156 g, 0.1 mmol), DMF/H2O (1:1; 4 mL), and HNO3 (100 μL, 1.6 mmol) were replaced by 4,4′-bipy (0.0156 g, 0.1 mmol), DMF/ H2O (1:3; 4 mL), and HNO3 (50 μL, 0.8 mmol). Colorless blockshaped crystals were obtained in 84% yield based on Cd(NO3)2·4H2O. Elem anal. Calcd for C26H26N2O14Cd2 (Mr = 815.29): C, 38.37; H, 3.04; N, 3.48. Found: C, 38.30; H, 3.21; N, 3.44. IR data (KBr, cm−1): 3399 (br), 1606 (m), 1536 (s), 1418 (s), 1366 (s), 1220 (w), 1066 (w), 842 (m), 816 (m), 775 (m), 734 (s), 664 (m), 633 (m), 500 (m), 417 (m) (Figure S1c).

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RESULTS AND DISCUSSION Crystal Structures. The CPs 1−3 were prepared by solvothermal reactions of Cd(NO3)2·4H2O and mixed ligands of H4bptc and various N-donor ligands. A structural study shows that these three CPs display different dimensions of skeleton structures by changing the N-donor ligand (Scheme 1), which is related to the different positions of the coordination sites in the N-donor ligands and different steric hindrance of the N-donor ligands during the self-assembly process.32a In addition, the crystallizations of those CPs rely heavily on the reaction conditions such as temperature, concentration of the starting materials, pH, and the solvents.32b,c For synthesis of the CPs 1−3, the amount of acid and the ratio of DMF/H2O are different. The high pH value facilitates the deprotonation of H4bptc, which can be propitious to its coordination with Cd2+ ions.32d Moreover, the amount of H2O can affect the kinetics of the crystal formation process.32e Therefore, the pH and amount of H2O in the reaction system play important roles in the formation and structure of the CPs 1−3. Structure Description of 1. Single-crystal X-ray diffraction analysis shows that 1 crystallizes in the monoclinic space group P21/c. The asymmetric unit consists of one CdII ion, half of a bptc4− ligand, one 2,2′-bipy, and one coordinated water molecule. The CdII ion is seven-coordinated with a CdO5N2 coordination environment and displays a distorted pentagonalbipyramidal configuration: four carboxylate oxygen atoms from two bptc4− ligands, one oxygen atom from one coordinated water molecule [Cd−O bond lengths ranging from 2.283(5) Å to 2.648(6) Å], and two nitrogen atoms from 2,2′-bipy [Cd−N bond lengths of 2.318(7) and 2.354(8) Å] (Table S2 and Figure 1a). Each CdII ion is connected with five adjacent CdII ions by two bptc4− ligands with a chelating bidentate mode (μ1η1:η1) to form a trapezoidal chain, and the coordinated 2,2′bipy molecules are fixed on both sides of the chain (Figure 1b). The adjacent chains are connected to form a layer structure by hydrogen bonds of O3−H3A···O2 and O3−H3B···O4 formed by coordinated water molecules and carboxyl groups of bptc4− ligands (Figure 1c). The layers were further connected to form a 3D supramolecular framework via another type of hydrogen bond of C11−H11···O5 between 2,2′-bipy molecules and carboxyl groups of the bptc4− ligands (Figures 1d and S2). Structure Description of 2. The CP 2 crystallizes in the monoclinic space group P21/c. The asymmetric unit consists of two CdII ions, one bptc4− ligand, two 1,10-phen ligands, and four guest water molecules. Both Cd1 and Cd2 are sixcoordinated with a CdO4N2 coordination environment to adopt a distorted octahedral geometry and a distorted triprismatic configuration (Figure 2a): four carboxylate oxygen atoms from three bptc4− ligands with Cd−O bond lengths ranging from 2.254(3) to 2.482(3) Å and two nitrogen atoms from one 1,10-phen ligand with Cd−N bond lengths in the

Figure 1. (a) Coordination environment of the CdII ion in 1. (b) Trapezoidal chain. (c) 2D supramolecular network of 1 in the ac plane. (d) Supramolecular structure of 1 along the b axis.

Figure 2. (a) Coordination environments of CdII ions in 2. (b) Wavy layers along the b axis. (c and d) 3D supramolecular frameworks of 2 via π···π interactions of 1,10-phen molecules with a centroid−centroid distance of 3.6968(1) Å along the a and c axes, respectively.

range of 2.292(3)−2.349(4) Å (Table S3). Cd1 and Cd2 are bridged by two μ2-η1:η1 carboxylates of two bptc4− ligands to form a binuclear core with a Cd···Cd distance of 3.9831(2) Å. Each binuclear unit is connected with the adjacent eight binuclear units by 4-connected bptc4− to generate a wavy layered network. The coordinated 1,10-phen molecules are fixed on both sides of the skeleton (Figure 2b). The adjacent layers are further stacked with each other through 1,10-phen molecules via π···π interactions with a centroid−centroid distance of 3.6968(1) Å, forming a 3D supramolecular framework (Figure 2c,d). From a topological view, if all binuclear units and bptc4− can be viewed as 4-connected nodes, the structure is regarded as a topology with the Schläfli point symbol {44·62} (Figure S3). Structure Description of 3. The CP 3 crystallizes in the monoclinic space group C2/c. The asymmetric unit consists of one CdII ion, half of a bptc4− ligand, half of a 4,4′-bipy, one coordinated water molecule, and two lattice water molecules. Each CdII ion is six-coordinated in a distorted triprismatic C


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Inorganic Chemistry

Luminescence Properties. The luminescence of CPs with d10 transition metals is well documented recently.33 At room temperature, under excitation at 320 nm (1), 375 nm (2), and 340 nm (3), the emission spectra of the CPs 1−3 were recorded in the solid state, to show emission peaks at 355, 420, and 456 nm, respectively. The emission spectra of free ligands of the CPs 1−3 were carried out with the same excitation, and intraligand (π* → n or π* → π) emission was observed (Figure S8). In comparison with free ligands, the emissions of the CPs 1−3 can be assigned to ligand-centered luminescence instead of charge transfer between ligands and metals (LMCT/MLCT) because it is difficult for a CdII ion with a d10 configuration to be oxidized or reduced.11e,26d,34 The obvious red shifts of emission maxima for the CP 3 may originate from the coordination interactions of the organic ligands to the CdII ions.35 In addition, PXRD patterns of the CPs 1−3 suggest that the three CPs possess high water stability in wide pH ranges from 1 to 12 (1), from 2 to 12 (2), and from 1 to 13 (3), and the luminescent intensities of the CPs 1−3 are almost unchanged in the range of pH 4−10 (Figure S9). The timedependent luminescent studies show that the luminescent intensities of the CPs 1−3 suspended in an aqueous solution are almost independent of the testing time, which suggests that the CPs 1−3 have good dispersibility and stability in water (Figure S10). These phenomena encourage us to explore their luminescent sensing properties in water directly. Selective Detection of Cations. To further study the properties of the CPs 1−3 to detect metal cations, 10−3 M aqueous solutions containing AgNO3 or MClx (M = Li+, Na+, K+, Mg2+, Ca2+, Sr2+, Ba2+, Cr3+, Mn2+, Fe3+, Co2+, Ag+, Au3+, Zn2+, Cd2+, Hg2+, Al3+, and Pb2+) were prepared individually. Then, suspensions of 3 mg of the CPs 1−3 in 4 mL of each of these solutions were prepared. The luminescent intensities of these CP suspensions were recorded at room temperature. As shown in Figures 4 and S11, most cations possess different

configuration with a CdO5N coordination environment (Figure 3a): four carboxylate oxygen atoms from three bptc4− ligands

Figure 3. (a) Coordination environment of the CdII ion in 3. (b) Binuclear core. (c) 3D framework of 3 along the a axis. (d) Simplified topological net of 3.

and one oxygen atom from one coordinated water molecule with Cd−O bond lengths ranging from 2.232(6) to 2.472(6) Å and one nitrogen atom from 4,4′-bipy with a Cd−N bond length of 2.264(7) Å (Table S4). The carboxylate groups of fully deprotonated bptc4− ligands display chelating bidentate (μ1-η1:η1) and bridging bidentate (μ2-η1:η1) coordination modes. Two six-coordinated CdII ions are bridged by two μ2η1:η1 carboxylates of two bptc4− ligands to form a binuclear core with a Cd···Cd distance of 4.2596(1) Å (Figure 3b). One binuclear unit is connected with the eight adjacent binuclear units by four 4-connected bptc4− and two bridging 4,4′-bipy ligands to give a 3D framework (Figure 3c). The phenyl rings in bptc4− and 4,4′-bipy are noncoplanar with dihedral angles of 38.6° and 32.5°, respectively (Figure S4). A simplified network has been obtained by topological analysis, in which each binuclear CdII unit is regarded as a 6-connected node, all bptc4− ligands are considered as 4-connected nodes, and each bridging 4,4′-bipy ligand is viewed as a linker. As a result, the framework is a 4,6-connected network with the point symbol {3·42·52· 6}{32·42·52·64·74·8} (Figures 3d and S5). PXRD and TGA Analyses. PXRD were performed to confirm the phase purity of the CPs 1−3. As shown in Figure S6, the diffraction peaks of the CPs 1−3 are well-consistent with the simulated ones from the single-crystal data, implying high phase purity. In addition, TGA tests were carried out to study the thermal stabilities of the CPs 1−3 (Figure S7). For 1, the first weight loss of 4.06% (40−340 °C) corresponds to the loss of two coordinated water molecules (calcd 3.78%). For 2, the first weight loss of 7.18% (40−410 °C) is due to the loss of four lattice water molecules (calcd 7.32%). For 3, the first two weight losses of 9.04% (40−125 °C) and 4.38% (125−400 °C) are attributed to the loss of four lattice water molecules (calcd 8.84%) and two coordinated water molecules (calcd 4.42%), respectively. After 340 (1), 410 (2), and 400 °C (3), the skeletons of the CPs 1−3 begin to collapse because of decomposition of the organic ligands.

Figure 4. Changes of the luminescent intensities with the maximum emission peaks of the CPs 1−3 suspended in aqueous solutions with different metal cations (1 × 10−3 M).

effects on the emission of the CPs 1−3, while only Fe3+ ions exhibits an extreme quenching effect on the luminescence, with quenching efficiencies of 99% (1), 71% (2), and 88% (3) [quenching efficiency = (I0 − I)/I0 × 100%, where I0 and I are the maximum luminescent intensities before and after addition of the targeted species]. The result indicates that the CPs 1−3 can act as promising chemical sensors for Fe3+ ions. Luminescence titration experiments were carried out further to explore the detection capability of the CPs 1−3 for Fe3+ D


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Inorganic Chemistry

Figure 5. Emission spectra and SV plots of the CPs 1 (a and b), 2 (c and d), and 3 (e and f) in aqueous solutions with different concentrations of Fe3+ ions.

an energy-transfer process or self-absorption.38 Additionally, the nonlinear S−V plots indicate that the quenching behaviors for the Fe3+ ions of the CPs 1 and 3 combine static quenching with dynamic quenching, which can be fitted by an exponential quenching equation, I0/I = a exp(k[M]) + b, where a, b, and k are constants and [M] is the molar concentration of the Fe3+ ion.20c,39 For the CPs 1 and 3, these plots can be fitted to I0/I = 2.10 exp(4.10[M]) − 2.48 and I0/I = 7.96 exp(0.78[M]) − 8.19, respectively. On the basis of the values of a and k, the quenching constants for the Fe3+ ions were found to be 8.61 × 103 M−1 (1) and 6.21 × 103 M−1 (3), while for the CP 2, the S−V plot for the Fe3+ ions is linear at all concentrations, indicating that the quenching process for the Fe3+ ion is static quenching with a quenching constant of 3.07 × 103 M−1 (Figure 5d).40 The quenching constants for the Fe3+ ions of the CPs 1−3 are comparable to those of the previously reported CP sensors (Table S6). In comparison with the CPs 2 and 3, the CP 1 exhibits a maximum quenching efficiency for Fe3+ ions. Hence, interference experiments were further carried out for the CP 1. Fe3+ ions (10−2 M, 0.4 mL) and other metal ions (10−2 M, 0.4 mL) were introduced into aqueous solutions (3.2 mL) of the CP 1 to form suspensions (4 mL) containing Fe3+ ions and other metal ions with a final concentration of

ions. Figures 5a,c,e and S13 show that the luminescent intensities decrease as the concentrations of Fe3+ ions gradually increase for the CPs 1−3. When the concentrations were up to 250 ppm (1), 700 ppm (2), and 600 ppm (3), the quenching efficiencies reach 99% (1), 90% (2), and 98% (3) (Figure S12). Furthermore, as shown in the insets of Figure S13, for the CPs 1−3, the luminescent intensities and the concentrations of Fe3+ ions at lower concentrations show good linear relationships. Accordingly, the detection limits are calculated to be 2.76 ppm (1.02 × 10−5 M; 1), 5.85 ppm (2.17 × 10−5 M; 2), and 5.49 ppm (2.03 × 10−5 M; 3) by 3σ/k (σ = standard deviation of fluorescent tests for 10 blank solutions; k = slope of the calibration curve),36 which are among the best sensors in the other reported works for the Fe3+ ion (Table S6). Moreover, the luminescent quenching efficiency was quantitatively analyzed by the Stern−Volmer (S−V) equation, I0/I = Ksv[M] + 1,37 where I0 and I are the maximum luminescent intensities before and after the addition of Fe3+ ions, [M] is the molar concentration of Fe3+ ions, and KSV is the quenching constant (M−1). For the CPs 1 (Figure 5b) and 3 (Figure 5f), the S−V plots for Fe3+ ions were nearly linear at low concentrations and then deviated from linearity to increase exponentially at higher concentrations, which may be caused by E


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Inorganic Chemistry

Figure 6. (a) Luminescent intensities of 1 with mixed-metal cations (1 × 10−3 M). (b) Five cycle tests of the CP 1 for sensing Fe3+ ions.

10−3 M. Then, the emissions were recorded at room temperature. As shown in Figure 6a, after other cations were introduced, the significant quenching effect of the Fe3+ ions is not changed, which further confirms that the CP 1 has the ability of high-selective sensing for Fe3+ ions among the various cations. To study the recycling performance of the CP 1 for sensing Fe3+ ions, the sample was immersed in an aqueous solution containing 1 × 10−3 M Fe3+ ions. The emission intensity of the CP 1 can be restored by centrifuging the suspension and then washing with water several times. After five cycles, the luminescent intensities remain almost unchanged, and PXRD tests confirm the structural integrity of the recycled CP 1 (Figures 6b and S14). To study the luminescent quenching mechanism caused by Fe3+ ions, PXRD of the CPs 1−3 after sensing for Fe3+ ions was performed and is well-consistent with their simulated data (Figure S15). Thus, luminescent quenching resulting from the collapse of the frameworks can be ruled out. As we know, competitive absorption for irradiated light between the analytes and CPs can cause luminescent quenching if the absorption band of the analyte has an effective overlap with that of the CP. The extent of overlap of absorption spectra determines the probability of competitive absorption for irradiated light between the analytes and CPs.41a Moreover, in the case that the fluorophores and detected analytes are close to each other and the absorption spectra of the analytes overlap effectively with the emission spectra of the fluorophores, resonance energy transfer can occur from fluorophores to analytes, which can greatly enhance the luminescent quenching efficiency and improve the sensitivity of the luminescent sensors.41b Hence, UV−vis spectra of various metal ions in water were measured to further investigate the luminescent quenching mechanism caused by Fe3+ ions. As shown in Figure S16a, Fe3+ ions in water show the absorption range from 260 to 400 nm, which covers the absorption bands of the CPs 1−3 (240−370 nm) and, hence, there is a competitive absorption of the exciting light between the Fe3+ ions and the CPs 1−3. Upon excitation, the Fe3+ ions can essentially filter light adsorption of the CPs 1−3, thus resulting in quenching of the luminescence of the CPs 1−3. Furthermore, the absorption spectra of the Fe3+ ions partly overlap with the emission spectra of the CP 1, while they overlap a little with the emission spectra of the CPs 2 and 3 (Figure S16b), which indicates that a resonance energy-transfer mechanism may also work for sensing Fe3+ ions by the CP 1 and may be the main reason for the CP 1 having maximum quenching constants for Fe3+ ions compared with the CPs 2 and 3.38c,42 Selective Detection of Anions. Meanwhile, various anions were selected to investigate the function of the CPs

1−3 for the detection of anions. As shown in Figures 7 and S17, the Cr2O72− and CrO42− ions cause significant luminescent

Figure 7. Changes of the luminescent intensities with the maximum emission peaks of the CPs 1−3 suspended in aqueous solutions containing various anions (1 × 10−3 M).

quenching effects, with the quenching efficiencies of 98% and 92% (1), 70% and 69% (2), and 92% and 78% (3), respectively, while other anions possess a slight effect on the luminescent intensities. For the CPs 1−3, luminescence titration experiments were carried out to study the sensitivity for Cr2O72− and CrO42− ions. The titration plots revealed that the emission intensities of the CPs 1−3 decreased with increasing concentrations of the Cr 2 O 7 2− /CrO 4 2− ions. For the Cr2O72−/CrO42− ions, when their concentrations were up to 300/500 ppm (1) (Figure 8a,c), 600/900 ppm (2) (Figure S18a,c), and 400/700 ppm (3) (Figure S19a,c), the quenching efficiencies could reach 99% (1), 97% (2), and 98% (3) (Figure S20). The insets of Figure S21 show that there are good linear relationships between the emission intensities of the CPs 1−3 and the lower concentrations of the Cr2O72−/CrO42− ions. Similarly, the detection limits are calculated as 2.17 ppm (7.38 × 10−6 M; 1), 17.34 ppm (5.89 × 10−5 M; 2), and 3.98 ppm (1.36 × 10−5 M; 3) for Cr2O72− ions and 1.51 ppm (7.79 × 10−6 M; 1), 20.66 ppm (1.06 × 10−4 M; 2), and 3.10 ppm (1.60 × 10−5 M; 3) for CrO42− ions by 3σ/k (σ = standard deviation of the fluorescent tests for 10 blank solutions; k = slope of the calibration curve).36 As shown in Table S7, the detection limits of the CPs 1−3 for Cr2O72−/CrO42− ions are comparable to those of other known luminescent sensors. Furthermore, the S−V plots for Cr2O72−/CrO42− ions were both nonlinear for the CPs 1 (Figure 8b,d), 2 (Figure S18b,d), and 3 (Figure S19b,d), which could be caused by the energy-transfer process or self-absorption.38 The results indicate that the sensing for Cr2O72−/CrO42− ions of the CPs 1−3 is the process of a F


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Inorganic Chemistry

Figure 8. Emission spectra and S−V plots of 1 in aqueous solution with different concentrations of Cr2O72− (a and b) and CrO42− (c and d) ions.

Figure 9. (a and b) Luminescent intensities of 1 with mixed-metal cations (1 × 10−3 M). (c and d) Five cycle tests of the CP 1 for sensing CrO42− and Cr2O72− ions.

CrO42− ions. According to the constants a and k of these fitted S−V plots, the quenching constants KSV for the Cr2O72−/ CrO42− ions were obtained as 1.17 × 104 M−1 (1), 2.09 × 103 M−1 (2), and 9.34 × 103 M−1 (3) for Cr2O72− ions and 7.95 × 103 M−1 (1), 1.09 × 103 M−1 (2), and 5.38 × 103 M−1 (3) for CrO42− ions, which are comparable to those for other reported CP sensors with excellent performance (Table S7). Given that various types of anions always exist in wastewater and the CP 1 is the most sensitive to Cr2O72−/CrO42− ions with the highest quenching efficiency, it is necessary to explore the effect of mixed anions on the emission. The experimental details are

combination of static and dynamic quenching.20c These phenomena are similar to the CPs 1 and 3 for sensing Fe3+ ions. The exponential quenching equations mentioned above, I0/I = a exp(k[M]) + b, where a, b, and k are constants and [M] is the molar concentration of the Cr2O72−/CrO42− ions, can be used for fitting of these S−V plots to give the relationships between I0/I versus [M]: I0/I = 3.89 exp(3.02[M]) − 4.77 (1), I0/I = 2.75 exp(0.76[M]) − 2.87 (2), and I0/I = 5.40 exp(1.73[M]) − 5.96 (3) for Cr2O72− ions and I0/I = 9.24 exp(0.86[M]) − 9.40 (1), I0/I = 1.84 exp(0.59[M]) − 1.92 (2), and I0/I = 10.15 exp(0.53[M]) − 10.58 (3) for G


Article

Inorganic Chemistry similar to those of other cations interfering with Fe3+ ions, and only Cr2O72−/CrO42− ions are used instead of Fe3+ ions. The sharp quenching effect of the Cr2O72−/CrO42− ions on the CP 1 is not changed after the addition of other anions, which suggests that 1 can selectively detect Cr2O72−/CrO42− ions among the various anions (Figure 9a,b). Moreover, after the detection of Cr2O72−/CrO42− ions, the sample can also be recycled for five runs by simple centrifugation and washing with water (Figure 9c,d). PXRD patterns of the recycled samples still well correspond with the simulated data of the CP 1 (Figure S14). To investigate the luminescent quenching mechanism caused by Cr2O72−/CrO42− ions, PXRD of the CPs 1−3 after sensing for Cr2O72−/CrO42− ions was performed. Figure S15 shows that, after detecting Cr2O72−/CrO42− ions, the skeletons of the CPs 1−3 remain intact. UV−vis absorption spectra of various anions in aqueous solution were further recorded. As shown in Figure S22, Cr2O72−/CrO42− ions in aqueous solution show two broad absorption bands from 230 to 420 nm: 257 and 360 nm for Cr2O72− ions and 273 and 372 nm for CrO42− ions, which cover the absorption bands of the CPs 1−3 (240−370 nm), indicating that there is competitive absorption of the exciting light between the Cr2O72−/CrO42− ions and the CPs 1−3. Besides, the emission spectra of the CPs 1−3 coincide with the absorption bands of the Cr2O72−/CrO42− ions to different degrees. Among them, the emission spectra of the CP 1 almost completely covers the absorption bands of Cr2O72− at 360 nm and of CrO42− at 372 nm, which is also the main reason that the CP 1 possesses higher sensitivity and quenching efficiency constant than the CPs 2 and 3. Hence, for the CPs 1−3, the luminescence quenching by Cr2O72−/CrO42− ions may be the process involving competitive absorption on light excitation between the Cr2O72−/CrO42− ions and the CPs 1−3 as well as energy resonance transfer from donors (CPs 1−3) to acceptors (Cr2O72−/CrO42− ions).29,43

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CONCLUSIONS

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ASSOCIATED CONTENT

Crystallographic data, additional crystal structure diagrams, PXRD and TGA patterns, excitation and emission spectra of CPs, and UV−vis spectra of different ions (PDF) Accession Codes

CCDC 1551327−1551329 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing [email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.

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AUTHOR INFORMATION

Corresponding Authors

*E-mail: [email protected]. *E-mail: [email protected]. ORCID

Wei Shi: 0000-0001-6130-1227 Peng Cheng: 0000-0003-0396-1846 Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (Grants 21622105 and 91422302), the Ministry of Education of China (Grant B12015), the Natural Science Foundation of Tianjin (Grant 15JCYBJC47000) and the Fundamental Research Funds for the Central Universities.

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REFERENCES

(1) (a) Carter, K. P.; Young, A. M.; Palmer, A. E. Fluorescent Sensors for Measuring Metal Ions in Living Systems. Chem. Rev. 2014, 114, 4564−4601. (b) Barba-Bon, A.; Costero, A. M.; Gil, S.; Parra, M.; Soto, J.; Martinez-Manez, R.; Sancenon, F. A new selective fluorogenic probe for trivalent cations. Chem. Commun. 2012, 48, 3000−3002. (2) (a) Zhou, W. H.; Saran, R.; Liu, J. W. Metal Sensing by DNA. Chem. Rev. 2017, 117, 8272−8325. (b) Liu, X. F.; Theil, E. C. Ferritins: Dynamic Management of Biological Iron and Oxygen Chemistry. Acc. Chem. Res. 2005, 38, 167−175. (3) (a) Thompson, C. M.; Kirman, C. R.; Proctor, D. M.; Haws, L. C.; Suh, M.; Hays, S. M.; Hixon, J. G.; Harris, M. A. A chronic oral reference dose for hexavalent chromium-induced intestinal cancer. J. Appl. Toxicol. 2014, 34, 525−536. (b) Zhitkovich, A. Importance of chromium−DNA adducts in mutagenicity and toxicity of chromium (VI). Chem. Res. Toxicol. 2005, 18, 3−11. (4) Manning, F. C.; Blankenship, L. J.; Wise, J. P.; Xu, J.; Bridgewater, L. C.; Patierno, S. R. Induction of internucleosomal DNA fragmentation by carcinogenic chromate: relationship to DNA damage, genotoxicity, and inhibition of macromolecular synthesis. Environ. Health Persp. 1994, 102, 159−167. (5) (a) Zhou, H. C.; Kitagawa, S. Metal-Organic Frameworks (MOFs). Chem. Soc. Rev. 2014, 43, 5415−5418. (b) Heine, J.; MüllerBuschbaum, K. Engineering metal-based luminescence in coordination polymers and metal-organic frameworks. Chem. Soc. Rev. 2013, 42, 9232−9242. (6) (a) Islamoglu, T.; Goswami, S.; Li, Z. Y.; Howarth, A. J.; Farha, O. K.; Hupp, J. T. Postsynthetic Tuning of Metal-Organic Frameworks for Targeted Applications. Acc. Chem. Res. 2017, 50, 805−813. (b) 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. (c) Li, M.; Li, D.; O’Keeffe, M.; Yaghi, O. M. Topological Analysis of MetalOrganic Frameworks with Polytopic Linkers and/or Multiple Building

In summary, three new luminescent water-stable cadmium CPs with the structural dimensions from a 1D ladder chain to a 2D layer to a 3D porous framework have been solvothermally synthesized by a mixed-ligand strategy. The research on the luminescent properties shows that the CPs 1−3 can be an excellent discriminative probe for the highly selective and sensitive detection of Fe3+ and Cr2O72−/CrO42− ions in water, especially the CP 1 with a 1D structure. For the CPs 1−3, the luminescent quenching mechanism involves competitive absorption upon light excitation between the Fe3+/Cr2O72−/ CrO42− ions and the CPs 1−3 as well as energy resonance transfer from donors (CPs 1 and 3) to acceptors (Fe3+/ Cr2O72−/CrO42− ions). The mechanism of the CP 2 for sensing Fe3+ ions involves only competitive absorption upon light excitation between the Fe3+ ions and the CP 2. This work illustrated that even using 1D CPs as fluorescent sensors with highly selective and sensitive detection of cations/anions in an aqueous medium is rather rare, to the best of our knowledge, but it should be paid more attention in the future.

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.7b01790. H


Article

Inorganic Chemistry Units and the Minimal Transitivity Principle. Chem. Rev. 2014, 114, 1343−1370. (7) (a) Zhai, Q. G.; Bu, X. H.; Zhao, X.; Li, D. S.; Feng, P. Y. Pore Space Partition in Metal-Organic Frameworks. Acc. Chem. Res. 2017, 50, 407−417. (b) Férey, G.; Serre, C.; Devic, T.; Maurin, G.; Jobic, H.; Llewellyn, P. L.; De Weireld, G.; Vimont, A.; Daturi, M.; Chang, J. S. Why hybrid porous solids capture greenhouse gases? Chem. Soc. Rev. 2011, 40, 550−562. (c) Murray, L. J.; Dinca, M.; Long, J. R. Hydrogen storage in metal-organic frameworks. Chem. Soc. Rev. 2009, 38, 1294− 1314. (8) (a) Liu, J. W.; Chen, L. F.; Cui, H.; Zhang, J. Y.; Zhang, L.; Su, C. Y. Applications of metal-organic frameworks in heterogeneous supramolecular catalysis. Chem. Soc. Rev. 2014, 43, 6011−6061. (b) Dhakshinamoorthy, A.; Garcia, H. Metal-organic frameworks as solid catalysts for the synthesis of nitrogen-containing heterocycles. Chem. Soc. Rev. 2014, 43, 5750−5765. (c) Zhang, T.; Lin, W. B. Metalorganic frameworks for artificial photosynthesis and photocatalysis. Chem. Soc. Rev. 2014, 43, 5982−5993. (9) (a) Liu, K.; Zhang, X. J.; Meng, X. X.; Shi, W.; Cheng, P.; Powell, A. K. Constraining the coordination geometries of lanthanide centers and magnetic building blocks in frameworks: a new strategy for molecular nanomagnets. Chem. Soc. Rev. 2016, 45, 2423−2439. (b) Zhang, X. J.; Vieru, V.; Feng, X. W.; Liu, J. L.; Zhang, Z. J.; Na, B.; Shi, W.; Wang, B. W.; Powell, A. K.; Chibotaru, L. F.; Gao, S.; Cheng, P.; Long, J. R. Influence of Guest Exchange on the Magnetization Dynamics of Dilanthanide Single-Molecule-Magnet Nodes within a Metal-Organic Framework. Angew. Chem., Int. Ed. 2015, 54, 9861− 9865. (10) (a) Horcajada, P.; Chalati, T.; Serre, C.; Gillet, B.; Sebrie, C.; Baati, T.; Eubank, J. F.; Heurtaux, D.; Clayette, P.; Kreuz, C.; Chang, J. S.; Hwang, Y. K.; Marsaud, V.; Bories, P. N.; Cynober, L.; Gil, S.; Férey, G.; Couvreur, P.; Gref, R. Porous metal-organic-framework nanoscale carriers as a potential platform for drug delivery and imaging. Nat. Mater. 2010, 9, 172−178. (b) Huxford, R. C.; deKrafft, K. E.; Boyle, W. S.; Liu, D.; Lin, W. B. Lipid-coated nanoscale coordination polymers for targeted delivery of antifolates to cancer cells. Chem. Sci. 2012, 3, 198−304. (c) Horcajada, P.; Gref, R.; Baati, T.; Allan, P. K.; Maurin, G.; Couvreur, P.; Férey, G.; Morris, R. E.; Serre, C. Metal-organic frameworks in biomedicine. Chem. Rev. 2012, 112, 1232−1268. (11) (a) Hu, Z. C.; Deibert, B. J.; Li, J. Luminescent metal-organic frameworks for chemical sensing and explosive detection. Chem. Soc. Rev. 2014, 43, 5815−5840. (b) Lustig, W. P.; Mukherjee, S.; Rudd, N. D.; Desai, A. V.; Li, J.; Ghosh, S. K. Metal-organic frameworks: functional luminescent and photonic materials for sensing applications. Chem. Soc. Rev. 2017, 46, 3242−3285. (c) Cui, Y. J.; Yue, Y. F.; Qian, G. D.; Chen, B. L. Luminescent functional metal-organic frameworks. Chem. Rev. 2012, 112, 1126−1162. (d) Chen, L.; Ye, J. W.; Wang, H. P.; Pan, M.; Yin, S. Y.; Wei, Z. W.; Zhang, L. Y.; Wu, K.; Fan, Y. N.; Su, C. Y. Ultrafast water sensing and thermal imaging by a metal-organic framework with switchable luminescence. Nat. Commun. 2017, 8, 15985−15994. (e) Wenger, O. S. Vapochromism in organometallic and coordination complexes: chemical sensors for volatile organic compounds. Chem. Rev. 2013, 113, 3686−3733. (f) Allendorf, M. D.; Bauer, C. A.; Bhakta, R. K.; Houk, R. J. T. Luminescent metal-organic frameworks. Chem. Soc. Rev. 2009, 38, 1330−1352. (12) (a) Tanaka, D.; Horike, S.; Kitagawa, S.; Ohba, M.; Hasegawa, M.; Ozawa, Y.; Toriumi, K. Anthracene array-type porous coordination polymer with host-guest charge transfer interactions in excited states. Chem. Commun. 2007, 30, 3142−3144. (b) Chen, B. L.; Wang, L. B.; Zapata, F.; Qian, G. D.; Lobkovsky, E. B. A luminescent microporous metal-organic framework for the recognition and sensing of anions. J. Am. Chem. Soc. 2008, 130, 6718−3719. (c) Karmakar, A.; Manna, B.; Desai, A. V.; Joarder, B.; Ghosh, S. K. Dynamic Metal-Organic Framework with Anion-Triggered Luminescence Modulation Behavior. Inorg. Chem. 2014, 53, 12225−12227. (d) Chen, B. L.; Yang, Y.; Zapata, F.; Lin, G.; Qian, G.; Lobkovsky, E. B. Luminescent open metal sites within a metal-organic framework for sensing small molecules. Adv. Mater. 2007, 19, 1693−1696. (e) Qiu, Y.; Liu, Z.; Li,

Y.; Deng, H.; Zeng, R.; Zeller, M. Reversible Anion Exchange and Sensing in Large Porous Materials Built from 4,4’-Bipyridine via π···π and H-Bonding Interactions. Inorg. Chem. 2008, 47, 5122−5128. (13) Fatima, N.; Mohammad, A. Thin-Layer Chromatography of Metal Ions in Formic Acid Medium on Impregnated and Unimpregnated Silica Gel G: Semiquantitative Determination of Fe3+, Cd2+, Th4+, Al3+, Zn2+, UO22+, VO2+, Ce4+, and Ni2+. Sep. Sci. Technol. 1984, 19, 429−443. (14) (a) Feldman, F. J.; Knoblock, E. C.; Purdy, W. C. The determination of chromium in biological materials by atomic absorption spectroscopy. Anal. Chim. Acta 1967, 38, 489−497. (b) Sun, Z.; Liang, P. Determination of Cr (III) and total chromium in water samples by cloud point extraction and flame atomic absorption spectrometry. Microchim. Acta 2008, 162, 121−125. (15) (a) Prakash, A.; Chandra, S.; Bahadur, D. Structural, magnetic, and textural properties of iron oxide-reduced graphene oxide hybrids and their use for the electrochemical detection of chromium. Carbon 2012, 50, 4209−4219. (b) Lin, D.; Wu, J.; Wang, M.; Yan, F.; Ju, H. Triple Signal Amplification of Graphene Film, Polybead Carried Gold Nanoparticles as Tracing Tag and Silver Deposition for Ultrasensitive Electrochemical Immunosensing. Anal. Chem. 2012, 84, 3662−3668. (16) Seby, F.; Charles, S.; Gagean, M.; Garraud, H.; Donard, O. F. X. Chromium speciation by hyphenation of high-performance liquid chromatography to inductively coupled plasma-mass spectrometry study of the influence of interfering ions. J. Anal. At. Spectrom. 2003, 18, 1386−1390. (17) Shi, P. F.; Zhao, B.; Xiong, G.; Hou, Y. L.; Cheng, P. Fast capture and separation of, and luminescent probe for, pollutant chromate using a multi-functional cationic heterometal-organic framework. Chem. Commun. 2012, 48, 8231−8233. (18) (a) Cao, L. H.; Shi, F.; Zhang, W. M.; Zang, S. Q.; Mak, T. C. W. Selective Sensing of Fe3+ and Al3+ Ions and Detection of 2,4,6Trinitrophenol by a Water-Stable Terbium-Based Metal-Organic Framework. Chem. - Eur. J. 2015, 21, 15705−15712. (b) Wen, L. L.; Zheng, X. F.; Lv, K.; Wang, C. G.; Xu, X. Y. Two Amino-Decorated Metal-Organic Frameworks for Highly Selective and Quantitatively Sensing of HgII and CrVI in Aqueous Solution. Inorg. Chem. 2015, 54, 7133−7135. (c) Zhou, Y. Y.; Shi, Y.; Geng, B.; Bo, Q. B. Highly Water-Stable Novel Lanthanide Wheel Cluster Organic Frameworks Featuring Coexistence of Hydrophilic Cagelike Chambers and Hydrophobic Nanosized Channels. ACS Appl. Mater. Interfaces 2017, 9, 5337−5347. (19) (a) Wong, K. L.; Law, G. L.; Yang, Y. Y.; Wong, W. T. A highly porous luminescent terbium-organic framework for reversible anion sensing. Adv. Mater. 2006, 18, 1051−1054. (b) Xu, H.; Cao, C. S.; Zhao, B. A water-stable lanthanide-organic framework as a recyclable luminescent probe for detecting pollutant phosphorus anions. Chem. Commun. 2015, 51, 10280−10283. (20) (a) Yin, S. Y.; Zhu, Y. X.; Pan, M.; Wei, Z. W.; Wang, H. P.; Fan, Y. N.; Su, C. Y. Nanosized NIR-Luminescent Ln Metal-Organic Cage for Picric Acid Sensing. Eur. J. Inorg. Chem. 2017, 3, 646−650. (b) Wang, F.; Wang, Y. T.; Yu, H.; Chen, J. X.; Gao, B. B.; Lang, J. P. One Unique 1D Silver(I)-Bromide-Thiol Coordination Polymer Used for Highly Efficient Chemiresistive Sensing of Ammonia and Amines in Water. Inorg. Chem. 2016, 55, 9417−9423. (c) Gong, W. J.; Ren, Z. G.; Li, H. X.; Zhang, J. G.; Lang, J. P. Cadmium(II) Coordination Polymers of 4-Pyr-poly-2-ene and Carboxylates: Construction, Structure, and Photochemical Double [2 + 2] Cycloaddition and Luminescent Sensing of Nitroaromatics and Mercury(II) Ions. Cryst. Growth Des. 2017, 17, 870−881. (d) Zhou, J. M.; Li, H. H.; Zhang, H.; Li, H. M.; Shi, W.; Cheng, P. A Bimetallic Lanthanide Metal-Organic Material as a Self-Calibrating Color-Gradient Luminescent Sensor. Adv. Mater. 2015, 27, 7072−7077. (e) Zhang, H.; Ma, J. G.; Chen, D. M.; Zhou, J. M.; Zhang, S. W.; Shi, W.; Cheng, P. Microporous heterometal-organic framework as a sensor for BTEX with high selectivity. J. Mater. Chem. A 2014, 2, 20450−20453. (f) Wang, L.; Fan, G. L.; Xu, X. F.; Chen, D. M.; Wang, L.; Shi, W.; Cheng, P. Detection of polychlorinated benzenes (persistent organic pollutants) I


Article

Inorganic Chemistry by a luminescent sensor based on a lanthanide metal-organic framework. J. Mater. Chem. A 2017, 5, 5541−5549. (21) (a) Zhang, S. Y.; Shi, W.; Cheng, P.; Zaworotko, M. J. A MixedCrystal Lanthanide Zeolite-like Metal-Organic Framework as a Fluorescent Indicator for Lysophosphatidic Acid, a Cancer Biomarker. J. Am. Chem. Soc. 2015, 137, 12203−12206. (b) Hao, J. N.; Yan, B. Determination of Urinary 1-Hydroxypyrene for Biomonitoring of Human Exposure to Polycyclic Aromatic Hydrocarbons Carcinogens by a Lanthanide-functionalized Metal-Organic Framework Sensor. Adv. Funct. Mater. 2017, 27, 1603856−1603863. (22) Pramanik, S.; Zheng, C.; Zhang, X.; Emge, T. J.; Li, J. New microporous metal-organic framework demonstrating unique selectivity for detection of high explosives and aromatic compounds. J. Am. Chem. Soc. 2011, 133, 4153−4155. (23) (a) Lu, Y.; Yan, B. A ratiometric fluorescent pH sensor based on nanoscale metal-organic frameworks (MOFs) modified by europium (III) complexes. Chem. Commun. 2014, 50, 13323−13326. (b) Li, H. Y.; Wei, Y. L.; Dong, X. Y.; Zang, S. Q.; Mak, T. C. W. Novel Tb-MOF Embedded with Viologen Species for Multi-Photofunctionality: Photochromism, Photomodulated Fluorescence, and Luminescent pH Sensing. Chem. Mater. 2015, 27, 1327−1331. (c) Xu, X. Y.; Yan, B. An efficient and sensitive fluorescent pH sensor based on amino functional metal-organic frameworks in aqueous environment. Dalton Trans. 2016, 45, 7078−7084. (24) (a) Lv, R.; Wang, J.; Zhang, Y.; Li, H.; Yang, L.; Liao, S.; Gu, W.; Liu, X. An amino-decorated dual-functional metal-organic framework for highly selective sensing of Cr(III) and Cr(VI) ions and detection of nitroaromatic explosives. J. Mater. Chem. A 2016, 4, 15494−15500. (b) Huang, W. H.; Li, J. Z.; Liu, T.; Gao, L. S.; Jiang, M.; Zhang, Y. N.; Wang, Y. Y. A stable 3D porous coordination polymer as multichemosensor to Cr(IV) anion and Fe(III) cation and its selective adsorption of malachite green oxalate dye. RSC Adv. 2015, 5, 97127− 97132. (c) Feng, X.; Li, R.; Wang, L.; Ng, S. W.; Qin, G.; Ma, L. A series of homonuclear lanthanide coordination polymers based on a fluorescent conjugated ligand: syntheses, luminescence and sensor for pollutant chromate anion. CrystEngComm 2015, 17, 7878−7887. (d) Li, G. P.; Liu, G.; Li, Y. Z.; Hou, L.; Wang, Y. Y.; Zhu, Z. Uncommon Pyrazoyl-Carboxyl Bifunctional Ligand-Based Microporous Lanthanide Systems: Sorption and Luminescent Sensing Properties. Inorg. Chem. 2016, 55, 3952−3959. (e) Xiang, Z.; Fang, C.; Leng, S.; Cao, D. An amino group functionalized metal-organic framework as a luminescent probe for highly selective sensing of Fe3+ ions. J. Mater. Chem. A 2014, 2, 7662−7665. (f) Zhou, X. H.; Li, L.; Li, H. H.; Li, A.; Yang, T.; Huang, W. A flexible Eu(III)-based metalorganic framework: turn-off luminescent sensor for the detection of Fe(III) and picric acid. Dalton Trans. 2013, 42, 12403−12409. (g) Zhao, X. L.; Tian, D.; Gao, Q.; Sun, H. W.; Xu, J.; Bu, X. H. A chiral lanthanide metal-organic framework for selective sensing of Fe (III) ions. Dalton Trans. 2016, 45, 1040−1046. (25) (a) Meng, Q. G.; Xin, X. L.; Zhang, L. L.; Dai, F. N.; Wang, R. M.; Sun, D. F. A multifunctional Eu MOF as a fluorescent pH sensor and exhibiting highly solvent-dependent adsorption and degradation of rhodamine B. J. Mater. Chem. A 2015, 3, 24016−24021. (b) Zhang, S. Y.; Zhang, X. P.; Li, H. M.; Niu, Z.; Shi, W.; Cheng, P. DualFunctionalized Metal-Organic Frameworks Constructed from Hexatopic Ligand for Selective CO2 Adsorption. Inorg. Chem. 2015, 54, 2310−2314. (c) Zhang, L. Y.; Song, T. Y.; Xu, J. N.; Sun, J. Y.; Zeng, S. L.; Wu, Y. C.; Fan, Y.; Wang, L. Polymorphic Ln (III) and BPTCbased porous metal-organic frameworks with visible, NIR photoluminescent and magnetic properties. CrystEngComm 2014, 16, 2440− 2451. (d) He, H. J.; Zhang, L. N.; Deng, M. L.; Chen, Z. X.; Ling, Y.; Chen, J. X.; Zhou, Y. M. Acid-induced Zn (ii)-based metal-organic frameworks for encapsulation and sensitization of lanthanide cations. CrystEngComm 2015, 17, 2294−2300. (26) (a) Wang, R. W.; Meng, Q. G.; Zhang, L. L.; Wang, H. F.; Dai, F. N.; Guo, W. Y.; Zhao, L. M.; Sun, D. F. Investigation of the effect of pore size on gas uptake in two fsc metal-organic frameworks. Chem. Commun. 2014, 50, 4911−4914. (b) Xu, B.; Lin, X.; He, Z. Z.; Lin, Z. J.; Cao, R. A unique 2D→3D polycatenation cobalt(II)-based

molecule magnet showing coexistence of paramagnetism and canted antiferromagnetism. Chem. Commun. 2011, 47, 3766−3768. (c) Chen, Z.; Gao, D. L.; Diao, C. H.; Liu, Y.; Ren, J.; Chen, J.; Zhao, B.; Shi, W.; Cheng, P. Syntheses, Structures Tuned by 4,4’-Bipyridine and Magnetic Properties of a Series of Transition Metal Compounds Containing o-Carboxylphenoxyacetate Acid. Cryst. Growth Des. 2012, 12, 1201−1211. (d) Sun, D.; Han, L. L.; Yuan, S.; Deng, Y. K.; Xu, M. Z.; Sun, D. F. Four new Cd (II) coordination polymers with mixed multidentate N-donors and biphenyl-based polycarboxylate ligands: syntheses, structures, and photoluminescent properties. Cryst. Growth Des. 2013, 13, 377−385. (e) Ma, L. F.; Li, C. P.; Wang, L. Y.; Du, M. CoII and ZnII coordination frameworks with benzene-1,2,3-tricarboxylate tecton and flexible dipyridyl co-ligand: a new type of entangled architecture and a unique 4-connected topological network. Cryst. Growth Des. 2011, 11, 3309−3312. (27) Li, H. H.; Shi, W.; Zhao, K. N.; Li, H.; Bing, Y. M.; Cheng, P. Enhanced Hydrostability in Ni-Doped MOF-5. Inorg. Chem. 2012, 51, 9200−9207. (28) (a) Gadzikwa, T.; Zeng, B. S.; Hupp, J. T.; Nguyen, S. T. Ligand-elaboration as a strategy for engendering structural diversity in porous metal-organic framework compounds. Chem. Commun. 2008, 31, 3672−3674. (b) Du, M.; Jiang, X. J.; Zhao, X. J. Molecular Tectonics of Mixed-Ligand Metal-Organic Frameworks: Positional Isomeric Effect, Metal-Directed Assembly, and Structural Diversification. Inorg. Chem. 2007, 46, 3984−3995. (29) Liu, J. J.; Ji, G. F.; Xiao, J. N.; Liu, Z. L. Ultrastable 1D Europium Complex for Simultaneous and Quantitative Sensing of Cr(III) and Cr(VI) Ions in Aqueous Solution with High Selectivity and Sensitivity. Inorg. Chem. 2017, 56, 4197−4205. (30) (a) Sheldrick, G. M. A short history of SHELX. Acta Crystallogr., Sect. A: Found. Crystallogr. 2008, 64, 112−122. (b) Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J.; Howard, J. A. K.; Puschmann, H. OLEX2: a complete structure solution, refinement and analysis program. J. Appl. Crystallogr. 2009, 42, 339−341. (31) Spek, A. L. PLATON, A Multipurpose Crystallographic Tool; Utrecht University: Utrecht, The Netherlands, 2001. (32) (a) Maity, D. K.; Halder, A.; Ghosh, S.; Ghoshal, D. Azo Functionalized 5-Nitro-1,3-benzenedicarboxylate Based Coordination Polymers with Different Dimensionality and Functionality. Cryst. Growth Des. 2016, 16, 4793−4804. (b) Ramanan, A.; Whittingham, M. S. How Molecules Turn into Solids: the Case of Self-Assembled MetalOrganic Frameworks. Cryst. Growth Des. 2006, 6, 2419−2412. (c) Sonnauer, A.; Hoffmann, F.; Fröba, M.; Kienle, L.; Duppel, V.; Thommes, M.; Serre, C.; Férey, G.; Stock, N. Giant Pores in a Chromium 2,6-Naphthalenedicarboxylate Open-Framework Structure with MIL-101 Topology. Angew. Chem., Int. Ed. 2009, 48, 3791−3794. (d) Wu, S. T.; Long, L. S.; Huang, R. B.; Zheng, L. S. pH-Dependent Assembly of Supramolecular Architectures from 0D to 2D Networks. Cryst. Growth Des. 2007, 7, 1746−1752. (e) Zahn, G.; Zerner, P.; Lippke, J.; Kempf, F. L.; Lilienthal, S.; Schröder, C. A.; Schneider, A. M.; Behrens, P. Insight into the mechanism of modulated syntheses: in situ synchrotron diffraction studies on the formation of Zr-fumarate MOF. CrystEngComm 2014, 16, 9198−9207. (33) (a) Kumar, P.; Paul, A. K.; Deep, A. A luminescent nanocrystal metal organic framework for chemosensing of nitro group containing organophosphate pesticides. Anal. Methods 2014, 6, 4095−4101. (b) Lim, K. S.; Jeong, S. Y.; Kang, D. W.; Song, J. H.; Jo, H.; Lee, W. R.; Phang, W. J.; Moon, D.; Hong, C. S. Luminescent Metal-Organic Framework Sensor: Exceptional Cd2+ Turn-On Detection and First In Situ Visualization of Cd2+ Ion Diffusion into a Crystal. Chem. - Eur. J. 2017, 23, 4946. (c) Wang, Z. J.; Qin, L.; Chen, J. X.; Zheng, H. G. HBonding Interactions Induced Two Isostructural Cd(II) MetalOrganic Frameworks Showing Different Selective Detection of Nitroaromatic Explosives. Inorg. Chem. 2016, 55, 10999−11005. (d) Hu, F. L.; Shi, Y. X.; Chen, H. H.; Lang, J. P. A Zn(II) coordination polymer and its photocycloaddition product: syntheses, structures, selective luminescence sensing of iron(III) ions and selective absorption of dyes. Dalton Trans. 2015, 44, 18795−18803. (e) Chen, M. M.; Chen, L.; Li, H. X.; Brammer, L.; Lang, J. P. Highly J


Article

Inorganic Chemistry selective detection of Hg2+ and MeHgI by di-pyridin-2-yl-[4-(2pyridin-4-yl-vinyl)-phenyl]-amine and its zinc coordination polymer. Inorg. Chem. Front. 2016, 3, 1297−1305. (f) Cepeda, J.; RodríguezDiéguez, A. Tuning the luminescence performance of metal-organic frameworks based on d10 metal ions: from an inherent versatile behaviour to their response to external stimuli. CrystEngComm 2016, 18, 8556−8573. (g) Qiao, C. F.; Qu, X. N.; Yang, Q.; Wei, Q.; Xie, G.; Chen, S. P.; Yang, D. S. Instant high-selectivity Cd-MOF chemosensor for naked-eye detection of Cu(II) confirmed using in situ microcalorimetry. Green Chem. 2016, 18, 951−956. (34) Zhang, Y.; Liu, Q. F.; Geng, H. M. Solvent Molecule Controlled Zinc (II) Metal-Organic Frameworks with Different Topology. Z. Anorg. Allg. Chem. 2015, 641, 2380−2383. Chen, W. J.; Lin, Y. N.; Zhang, X. P.; Xu, N.; Cheng, P. A new cadmium-organic framework fluorescent sensor for Al3+ and Ca2+ ions in aqueous medium. Inorg. Chem. Commun. 2017, 79, 29−32. (35) (a) Hua, J. A.; Zhao, Y.; Kang, Y. S.; Lu, Y.; Sun, W. Y. Solventdependent zinc(II) coordination polymers with mixed ligands: selective sorption and fluorescence sensing. Dalton Trans. 2015, 44, 11524−11532. (b) Buragohain, A.; Yousufuddin, M.; Sarma, M.; Biswas, S. 3D Luminescent Amide-Functionalized Cadmium Tetrazolate Framework for Selective Detection of 2,4,6-Trinitrophenol. Cryst. Growth Des. 2016, 16, 842−851. (36) (a) Wu, J. X.; Yan, B. A dual-emission probe to detect moisture and water in organics based on green-Tb3+ post-coordinated metalorganic frameworks with red-carbon dots. Dalton Trans. 2017, 46, 7098−7105. (b) Recommendations for the Definition, Estimation and Use of the Detection Limit. Analyst 1987, 112, 199−20410.1039/ an9871200199. (37) Wen, G. X.; Wu, Y. P.; Dong, W. W.; Zhao, J.; Li, D. S.; Zhang, J. An Ultrastable Europium(III)-Organic Framework with the Capacity of Discriminating Fe2+/Fe3+ Ions in Various Solutions. Inorg. Chem. 2016, 55, 10114−10117. (38) (a) Zhang, S. R.; Du, D. Y.; Qin, J. S.; Bao, S. J.; Li, S. L.; He, W. W.; Lan, Y. Q.; Shen, P.; Su, Z. M. A fluorescent sensor for highly selective detection of Nitroaromatic explosives based on a 2D, extremely stable, metal-organic framework. Chem. - Eur. J. 2014, 20, 3589−3594. (b) Ma, H. L.; Wang, L.; Chen, J. H.; Zhang, X. J.; Wang, L.; Xu, N.; Yang, G. M.; Cheng, P. A multi-responsive luminescent sensor for organic small-molecule pollutants and metal ions based on a 4d-4f metal-organic framework. Dalton Trans. 2017, 46, 3526−3534. (c) Nagarkar, S. S.; Joarder, B.; Chaudhari, A. K.; Mukherjee, S.; Ghosh, S. K. Highly selective detection of nitro explosives by a luminescent metal-organic framework. Angew. Chem., Int. Ed. 2013, 52, 2881−2885. (39) (a) Sun, X. C.; He, J. K.; Meng, Y. T.; Zhang, L. C.; Zhang, S. C.; Ma, X. Y.; Dey, S.; Zhao, J.; Lei, Y. Microwave-assisted ultrafast and facile synthesis of fluorescent carbon nanoparticles from a single precursor: preparation, characterization and their application for the highly selective detection of explosive picric acid. J. Mater. Chem. A 2016, 4, 4161−4171. (b) Liu, J. Z.; Zhong, Y. C.; Lu, P.; Hong, Y. N.; Lam, J. W. Y.; Faisal, M.; Yu, Y.; Wong, K. S.; Tang, B. A superamplification effect in the detection of explosives by a fluorescent hyperbranched poly(silylenephenylene) with aggregation-enhanced emission characteristics. Polym. Chem. 2010, 1, 426−429. (40) Jin, J. C.; Pang, L. Y.; Yang, G. P.; Hou, L.; Wang, Y. Y. Two porous luminescent metal-organic frameworks: quantifiable evaluation of dynamic and static luminescent sensing mechanisms towards Fe3+. Dalton Trans. 2015, 44, 17222−17228. (41) (a) Zhao, D.; Liu, X. H.; Zhao, Y.; Wang, P.; Liu, Y.; Azam, M.; Al-Resayes, S. I.; Lu, Y.; Sun, W. Y. Luminescent Cd(II)-organic frameworks with chelating NH2 sites for selective detection of Fe(III) and antibiotics. J. Mater. Chem. A 2017, 5, 15797−15807. (b) Nagarkar, S. S.; Joarder, B.; Chaudhari, A. K.; Mukherjee, S.; Ghosh, S. K. Highly Selective Detection of Nitro Explosives by a Luminescent MetalOrganic Framework. Angew. Chem. 2013, 125, 2953−2957. (42) (a) Xing, B.; Li, H. Y.; Zhu, Y. Y.; Zhao, Z.; Sun, Z. G.; Yang, D.; Li, J. Two fluorescent lead phosphonates for highly selective sensing of nitroaromatics (NACs), Fe3+ and MnO4− ions. RSC Adv. 2016, 6,

110255−110265. (b) Wang, B.; Yang, Q.; Guo, C.; Sun, Y. X.; Xie, L. H.; Li, J. R. Stable Zr(IV)-Based Metal-Organic Frameworks with PreDesigned Functionalized Ligands for Highly Selective Detection of Fe(III) Ions in Water. ACS Appl. Mater. Interfaces 2017, 9, 10286− 10295. (43) (a) Parmar, B.; Rachuri, Y.; Bisht, K. K.; Laiya, R.; Suresh, E. Mechanochemical and Conventional Synthesis of Zn(II)/Cd(II) Luminescent Polymers Coordination: Dual Sensing Probe for Selective Detection of Chromate Anions and TNP in Aqueous Phase. Inorg. Chem. 2017, 56, 2627−2638. (b) Gu, T. Y.; Dai, M.; Young, D. J.; Ren, Z. G.; Lang, J. P. Luminescent Zn(II) Coordination Polymers for Highly Selective Sensing of Cr(III) and Cr(VI) in Water. Inorg. Chem. 2017, 56, 4668−4678.

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