Fabrication of Supramolecular Chirality from Achiral Molecules at the

Dec 15, 2017 - We present the investigation into the supramolecular chirality of 5-octadecyloxy-2-(2-pyridylazo)phenol (PARC18) at water/1,2-dichloroe...
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Fabrication of Supramolecular Chirality from Achiral Molecules at the Liquid/Liquid Interface Studied by Second Harmonic Generation Lu Lin,†,‡ Zhen Zhang,‡ Yuan Guo,*,‡,§ and Minghua Liu*,‡ †

National Center for Nanoscience and Technology, Beijing 100190, P. R. China Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China § University of Chinese Academy of Sciences, Beijing 100049, P. R. China ‡

S Supporting Information *

ABSTRACT: We present the investigation into the supramolecular chirality of 5-octadecyloxy-2-(2-pyridylazo)phenol (PARC18) at water/1,2-dichloroethane interface by second harmonic generation (SHG). We observe that PARC18 molecules form supramolecular chirality through self-assembly at the liquid/liquid interface although they are achiral molecules. The bulk concentration of PARC18 in the organic phase has profound effects on the supramolecular chirality. By increasing bulk concentration, the enantiomeric excess at the interface first grows and then decreases until it eventually vanishes. Further analysis reveals that the enantiomeric excess is determined by the twist angle of PARC18 molecules at the interface rather than their orientational angle. At lower and higher bulk concentrations, the average twist angle of PARC18 molecules approaches zero, and the assemblies are achiral; whereas at medium bulk concentrations, the average twist angle is nonzero, so that the assemblies show supramolecular chirality. We also estimate the coverage of PARC18 molecules at the interface versus the bulk concentration and fit it to Langmuir adsorption model. The result indicates that PARC18 assemblies show strongest supramolecular chirality in a half-full monolayer. These findings highlight the opportunities for precise control of supramolecular chirality at liquid/liquid interfaces by manipulating the bulk concentration.

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INTRODUCTION Supramolecular assemblies can find applications in enantioselective catalysis,1,2 nonlinear optics,3−6 and molecular devices.7,8 In the past decades, significant interests have been drawn to the construction of chiral assemblies9−17 and the mechanism of chiral induction, transcription, and amplification.18−25 So far, strategies for the fabrication of self-assemblies with supramolecular chirality have been well established, many of which concern chiral assembly from achiral molecules, referred to as building blocks, through π−π stacking, hydrogen bonding, coordination, and van der Waals interactions.12,26−29 It has been shown that achiral molecules can form special spatial arrangements, typically helices, under certain circumstances and give rise to supramolecular chirality.30 The handedness of the helices is determined by the helical directions in the assemblies, and it can be readily controlled by various methods, including chiral templates,31,32 stirring vortices,33,34 and magnetic forces.16 In contrast, there is very limited report on controlling the enantiomeric excess in supramolecular assemblies. As compared with bulk media, supramolecular chirality can be achieved more readily at interfaces because of the noncentrosymmetric nature in two dimensions.17 Up to now, © XXXX American Chemical Society

although fabrication and control of supramolecular chirality at gas/liquid, gas/solid, and liquid/solid interfaces have been systematically investigated,30,35−38 little information is available on supramolecular chirality at liquid/liquid interfaces. Liquid/ liquid interfaces play important roles in many chemical and biological processes such as membrane transport, electron transfer, solvent extraction, phase-transfer catalysis, and nanoparticle assembly.39−46 Molecules adsorbed at liquid/ liquid interfaces are more likely to form aggregates because the capacity of an liquid/liquid interface is ∼10−10 mol/cm2, almost two orders smaller than that of the air/water interface.47 Watarai and coworkers have carried out pioneering studies in this field, demonstrating that achiral porphyrin derivatives could form chiral aggregates at liquid/liquid interfaces.48−53 Nevertheless, detailed information on the fabrication of supramolecular chirality at liquid/liquid interfaces is still lacking because conventional methods for chirality detection, such as circular dichroism (CD), optical rotatory dispersion (ORD), and scanning probe microscopy (SPM), are not Received: December 7, 2017 Revised: December 14, 2017 Published: December 15, 2017 A

DOI: 10.1021/acs.langmuir.7b04170 Langmuir XXXX, XXX, XXX−XXX

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75° with respect to the surface normal. SHG signals at 400 nm were collected in the reflected direction with a high-gain photomultiplier tube (R585, Hamamatsu) and a gated photon counter (SR400, Stanford Research Systems). The incident polarization was continuously adjusted with a half-wave plate driven by a computercontrolled stepper motor. The output polarization was fixed at either s or p with an analyzer.

suitable for characterization of chirality at liquid/liquid interfaces. In the past two decades, second-order nonlinear optical spectroscopy, including second harmonic generation (SHG) and sum frequency generation (SFG), has proven to be powerful tools in the studies of interfacial chirality due to its interface-selectivity and chiral-sensitivity.54−56 In particular, they are more suitable for in situ probe of supramolecular chirality at the liquid/liquid interfaces. Comparison of the nonlinear optical intensities under different polarization combinations can quantitatively determine the interfacial chirality in terms of the chiral sign and the enantiomeric excess.23,57−67 Besides, molecular orientation and conformation at the interfaces can also be determined through polarization-resolved measurements.68−74 In this report, we employ SHG to investigate the fabrication of supramolecular chirality at water/1,2-dichloroethane interface and its dependence on the bulk concentration of the building blocks in the organic phase. 5-Octadecyloxy-2-(2pyridylazo)phenol (PARC18, Figure 1) is chosen as building

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RESULTS AND DISCUSSION The interfacial chirality and molecular orientation can be derived from the incident polarization dependence of the SHG intensities. Relations between the SHG intensity and the incident polarization can be expressed as follows60 Is ∝ |a1χxxz sin 2α + a 7χyxz cos2 α|2 Ip ∝ |(a 2χxxz + a3χzxx + a4χzzz ) cos2 α + a5χzxx 2 sin 2 α + a6χyxz sin α cos α|

where χijk are the nonzero tensor elements of the second-order susceptibility for chiral interfaces with in-plane isotropy. The subscript s denotes output polarization parallel to the interface and p denotes polarization in the plane defined by the surface normal and the direction of light propagating; ai (i = 1−7) are the Fresnel coefficients and α is the polarization of the incident light. A detailed description of eq 1 can be found in the Supporting Information. To quantitatively describe the enantiomeric excess, the degree of chiral excess (DCE) has been introduced, which is defined as59,67 2(I45° − I135°) ΔI = I I45° + I135°

(2)

In the following, we will first use s-polarized detection to characterize the supramolecular chirality because previous studies have pointed out that s-polarized detection is more sensitive to interfacial chirality compared with p-polarized detection,59 then we use the combination of s- and p-polarized detection to assess the orientational angle of PARC18 molecules at the interface. Figure 2 shows the s-polarized SHG curves at various bulk concentrations of PARC18 in the organic phase. At medium concentrations (0.025−0.075 mM), there is a remarkable difference between the SHG intensities when the incident polarization is at 45 or 135°, indicating the emergence of supramolecular chirality at the interface resulted from PARC18 stacking. At both lower and higher concentrations, on the contrary, the differences are almost negligible, indicating the absence of supramolecular chirality. Although surface optical activity can also be due to in-plane anisotropy,78,79 it occurs mostly in the case of Langmuir−Blodgett films or crystals. In our experiments, the interface is bounded by centrosymmetric bulk phases that should be with in-plane isotropy.80 Hence the optical activity observed here is from chiral aggregation of PARC18 molecules. These results demonstrate that the supramolecular chirality of PARC18 assemblies at the liquid/ liquid interface is strongly dependent on its bulk concentration in the organic phase. This phenomenon can be explained by considering the molecular densities at the liquid/liquid interface. At lower concentrations, the absence of supramolecular chirality can be ascribed to the relatively low density of PARC18 molecules at the interface where achiral PARC18 molecules mainly exist as monomers instead of assemblies. At higher concentrations, however, the disappearance of supra-

Figure 1. Molecular structure of PARC18 and definitions of orientational angle θ and twist angle ψ.

blocks mainly because PARC18 assemblies display strong supramolecular chirality at the air/aqueous interface.59,75 Herein we show that PARC18 assemblies exhibit supramolecular chirality at water/1,2-dichloroethane interface, and its bulk concentration in the organic phase can modulate this supramolecular chirality. We also estimate the orientational angle and twist angle of PARC18 molecules at the interface and discuss their effects on the supramolecular chirality. The orientational angle changes slightly over the concentration range, and the twist angle determines the supramolecular chirality. On the basis of our observation and analysis, we propose molecular mechanism of PARC18 chiral assembly at the liquid/liquid interface.

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(1)

EXPERIMENTAL SECTION

PARC18 was synthesized and purified as described in the literature.76,77 1,2-Dichloroethane (purity >99.8%) was purchased from Acros Organics and used as received. Ultrapure water (18.2 MΩ· cm) was supplied from a Millipore system. PARC18 was dissolved in 1,2-dichloroethane, and the liquid sample was contained in a square cell made of fused silica. For SHG experiments, a mode-locked femtosecond Ti:sapphire laser (Tsunami 3960C, Spectra-Physics) was used. The pulse width was 80 fs and the repetition rate was 82 MHz. The fundamental wavelength was 800 nm and the incident angle of the laser beam was B

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Figure 2. s-Polarized SHG curves at various bulk concentrations of PARC18 in the organic phase. The circles represent experimental results and the solid lines are fits to eq 1. At medium concentrations, the SHG intensities are different when the incident polarization is at 45 or 135°, indicating the existence of supramolecular chirality, whereas at lower or higher concentrations, the difference is negligible, which means the interface is achiral.

Figure 3. p-Polarized SHG curves at various bulk concentrations of PARC18 in the organic phase. The circles represent experimental results and the solid lines are fits to eq 1.

Obviously, details of the molecular structures at the interface are required to resolve this contradiction. The p-polarized SHG curves together with fits to eq 1 are shown in Figure 3. Combined with fitting of the s-polarized curves, four nonzero independent tensor elements, namely, χzzz, χzxx, χxxz, and χyxz, are obtained, as listed in the Supporting

molecular chirality seems rather counterintuitive. It has been reported that supramolecular chirality is generally more favorable at higher molecular densities in Langmuir monolayers at the air/water interface.13,60 As such, the higher concentrations might also have promoted the formation of the supramolecular chirality at the liquid/liquid interface. C

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Langmuir Information. These tensor elements are linear combinations of molecular hyperpolarizabilities βijk. Hence, by appropriately assuming the β terms, the molecular orientational angle can be quantitatively retrieved. At neutral pH, PARC18 adopts a planar geometry,81 which is usually treated as uniaxial with only one dominant molecular hyperpolarizability denoted as βccc.82 However, βccc does not contribute to the macroscopic chiral tensor element χyxz.55,63 Therefore, the uniaxial symmetry is invalid to characterize the supramolecular chirality of PARC18 at the liquid/liquid interface, and additional molecular hyperpolarizability must be taken into account. Considering that PARC18 molecule has approximately C2v symmetry with a planar geometry and contains a transition near resonant with the second harmonic frequency, it is reasonable to suggest another nonzero molecular hyperpolarizability βcaa.83 Then, the macroscopic tensor elements can be related to the molecular hyperpolarizabilities as63

Figure 4. Degree of chiral excess (red, left vertical axis) and molecular orientational angle (blue, right vertical axis) at various bulk concentrations. The supramolecular chirality is first enhanced with increasing bulk concentration and starts decreasing after 0.035 mM. The orientational angle shows a similar trend to that of the supramolecular chirality.

χzzz = Ns(⟨cos3 θ⟩βccc + ⟨sin 2 θ cos θ cos2 ψ ⟩βcaa) 1 Ns(⟨sin 2 θ cos θ⟩βccc + ⟨cos θ sin 2 ψ + cos3 θ cos2 ψ ⟩βcaa) 2 1 = Ns(⟨sin 2 θ cos θ⟩βccc − ⟨sin 2 θ cos θ cos2 ψ ⟩βcaa) 2 1 = Ns(⟨sin 2 θ sin ψ cos ψ ⟩βcaa) 2

χzxx = χxxz χyxz

(3)

where θ is the orientational angle, ψ is the twist angle, and Ns is the number density of PARC18 molecules at the interface. The angular brackets denote the average over the inside variables. In principle, given narrow distributions of the orientational and twist angles, the values of θ and ψ can be determined using eq 3 combined with the fitting results of the macroscopic tensor elements. However, as Simpson and coworkers have pointed out,84 although χyxz can serve as a useful tool for assessing the supramolecular chirality at the interface, directly relating it to the molecular structure is nontrivial. We hence use χzzz, χzxx, and χxxz to evaluate the molecular orientation. Details of the calculations can be found in the Supporting Information. To elucidate the correlation between the molecular orientation and the supramolecular chirality, we also calculate the DCE, an indicator of supramolecular chirality, using χyxz and χxxz. Figure 4 shows the plot of molecular orientation and DCE against the bulk concentration of PARC18. At the lowest concentration of 0.005 mM, the orientational angle is ∼32°, and the interface is nearly achiral. With the increasing bulk concentration, the orientational angle gets larger and reaches a maximum around 36° as the bulk concentration is 0.035 mM. Meanwhile, the DCE also gradually increases to a maximum ∼26%. After that, increasing the bulk concentration gives rise to the decrease in both the orientational angle and the supramolecular chirality. When the bulk concentration approaches 0.3 mM, the orientational angle reaches ∼30° and the supramolecular chirality vanishes. According to the definition, DCE is a function of both the orientation angle θ and the twist angle ψ. The dependence of DCE on θ and ψ is illustrated in Figure 5. For a certain ψ, DCE increases slowly with θ when θ is 45°. The range of the orientational angle can thus be categorized into two regions: insensitive region where DCE depends weakly on θ and sensitive region where DCE depends strongly on θ. In the present case, the value of θ lies in the insensitive region, and changes in θ have little effects on DCE.

Figure 5. 3D plot of DCE against the molecular orientational angle θ and the twist angle ψ. The ratio of βcaa and βccc is assumed to be 0.15. When θ is larger than 45°, DCE grows rapidly with θ; when θ is smaller than 45°, DCE is predominantly determined by ψ.

In other words, the twist angle ψ and its angular distribution predominantly determine the DCE. At a low bulk concentration, PARC18 molecules exist as monomers at the interface and can rotate freely with respect to the molecular axis, resulting in a random distribution of ψ and zero χyxz. As a result, the interface is achiral at a low bulk concentration. At medium bulk concentrations, more PARC18 molecules are adsorbed at the interface, which cause strong interactions between adsorbed molecules. Such intermolecular interactions make PARC18 molecules form assemblies in which they can no longer rotate freely. In the meantime, PARC18 molecules have to tilt to the interface and rotate with respect to its molecular axis to minimize the dipole−dipole repulsions between the head groups,85 which lead to a larger θ and a nonzero ψ with a narrower distribution. As a result, supramolecular chirality gradually appears at medium bulk concentrations. With continually increasing bulk concentration, adsorbed PARC18 molecules at the interface become crowded so that they have to tilt to the surface normal and rotate with respect to the molecular axis to minimize the occupied area. Eventually, PARC18 molecules adopt a face-toface geometry with a smaller orientation angle and a twist angle that is close to zero, followed by the disappearance of D

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Figure 6. Schematic illustration of PARC18 supramolecular chirality at the interface. Green blocks represent conjugated chromophores of PARC18 molecules. At low and high concentrations, PARC18 molecules tilt less to the interface and form achiral structures. At medium concentrations, PARC18 molecules tilt more to the interface and form chiral assemblies.

assemblies during compression 59 because in that case PARC18 molecules tilt more to the surface.87 In fact, at the air/water interface, PARC18 molecules experience weak hydrophobic and hydrophilic forces, which can hardly confine them to a 2D environment so that PARC18 molecules cannot achieve a face-to-face arrangement before the monolayer collapses upon compression. Compression of PARC18 monolayer at the air/water interface can cause decrease in orientational angle that hinders supramolecular chirality and increase in twist angle that promotes supramolecular chirality. The combined effects make the supramolecular chirality remain nearly unchanged through the compression process.

supramolecular chirality. Figure 6 illustrates possible arrangements of PARC18 molecules at the liquid/liquid interface. The proposed mechanism that crowded adsorption makes supramolecular chirality vanish is supported by previous studies on phospholipid monolayers at the air/water interface.86 In the liquid-expanded phase with moderate surface pressure, enantiomerically pure phospholipid molecules can form chiral aggregates, whereas in the liquid-condensed phase with high surface pressure they merely form achiral domains.86 One may expect multilayer adsorption of PARC18 molecules at the liquid/liquid interface when the bulk concentration is sufficiently high. To confirm whether there is multilayer, we estimate the relative density of PARC18 molecules at the interface using χzzz/cos3 θ, which is approximately proportional to Ns according to eq 3. The plot of the density against the bulk concentration can be well-fitted by Langmuir adsorption model (Figure 7), from which the

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CONCLUSIONS We investigate the supramolecular chirality of PARC18 assemblies and the orientation of PARC18 molecules at the water/1,2-dichloroethane interface as well as their dependence on the bulk concentration of PARC18 in the organic phase. It turns out that at low surface densities, PARC18 molecules at the interface exist mainly as monomers and the interface is achiral. At moderately higher surface densities around half-full coverage, PARC18 molecules tilt to the interface and form chiral assemblies to reduce the dipole−dipole repulsions between the headgroups, while near a fully covered monolayer PARC18 molecules tilt to the surface normal and adopt a faceto-face geometry, giving rise to achiral assemblies. The results presented here provide in-depth understanding of the formation of supramolecular chirality at the molecular level and benefit the modulation of supramolecular chirality. Because supramolecular chirality originates from asymmetric arrangement of the building blocks, it should be controlled by tuning the molecular orientation and twist. Liquid/liquid interface can provide suitable environment for controlling the molecular arrangement by adjusting the bulk concentration, the composition of the organic phase, and the pH or the ionic strength in the aqueous phase. It is thus expected that supramolecular chirality can be manipulable at the liquid/ liquid interface. Future work will be focused on precise and dynamic control of supramolecular chirality at liquid/liquid interfaces, which will be of general interest.

Figure 7. Coverage of PARC18 at the interface plotted against the bulk concentration. The circles represent the calculated coverage and the solid line is fit to the Langmuir model. The coverage is obtained by dividing the density with the maximum adsorption density from the fitting.

coverage is obtained by dividing the density with the maximum adsorption density. Details of the fitting can be found in the Supporting Information. Figures 7 and 4 indicate that the supramolecular chirality is more likely to form in a half-full monolayer. It is worth emphasizing that although similar trends for the orientational angle and supramolecular chirality have been observed, change in the supramolecular chirality here is subject to the twist angle of the PARC18 molecules rather than their orientation. This insight can interpret the different dependence of supramolecular chirality of PARC18 assemblies on bulk concentration or molecular density between monolayers at the liquid/liquid interface and at the air/water interface. At the air/water interface, surface pressure or molecular density has little effects on the supramolecular chirality of PARC18

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ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.langmuir.7b04170. Detailed description of eq 1, fitting results of SHG curves, calculations of orientational angle, and Langmuir fitting of the adsorption. (PDF) E

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(14) Jiménez-Millan, E.; Giner-Casares, J. J.; Martín-Romero, M. T.; Brezesinski, G.; Camacho, L. Chiral Textures inside 2D Achiral Domains. J. Am. Chem. Soc. 2011, 133, 19028−19031. (15) Kim, J.; Lee, J.; Kim, W. Y.; Kim, H.; Lee, S.; Lee, H. C.; Lee, Y. S.; Seo, M.; Kim, S. Y. Induction and Control of Supramolecular Chirality by Light in Self-Assembled Helical Nanostructures. Nat. Commun. 2015, 6, 6959. (16) Micali, N.; Engelkamp, H.; Van Rhee, P.; Christianen, P.; Scolaro, L. M.; Maan, J. Selection of Supramolecular Chirality by Application of Rotational and Magnetic Forces. Nat. Chem. 2012, 4, 201−207. (17) Fang, Y.; Ghijsens, E.; Ivasenko, O.; Cao, H.; Noguchi, A.; Mali, K. S.; Tahara, K.; Tobe, Y.; De Feyter, S. Dynamic Control over Supramolecular Handedness by Selecting Chiral Induction Pathways at the Solution-Solid Interface. Nat. Chem. 2016, 8, 711−717. (18) van Dijken, D. J.; Beierle, J. M.; Stuart, M. C.; Szymański, W.; Browne, W. R.; Feringa, B. L. Autoamplification of Molecular Chirality through the Induction of Supramolecular Chirality. Angew. Chem. 2014, 126, 5173−5177. (19) Lauceri, R.; Purrello, R. Transfer, Memory and Amplification of Chirality in Porphyrin Aggregates. Supramol. Chem. 2005, 17, 61−66. (20) Chen, P.; Ma, X.; Duan, P.; Liu, M. Chirality Amplification of Porphyrin Assemblies Exclusively Constructed from Achiral Porphyrin Derivatives. ChemPhysChem 2006, 7, 2419−2423. (21) Palmans, A. R. A.; Meijer, E. W. Amplification of Chirality in Dynamic Supramolecular Aggregates. Angew. Chem., Int. Ed. 2007, 46, 8948−8968. (22) Monti, D.; Venanzi, M.; Stefanelli, M.; Sorrenti, A.; Mancini, G.; Di Natale, C.; Paolesse, R. Chiral Amplification of Chiral Porphyrin Derivatives by Templated Heteroaggregation. J. Am. Chem. Soc. 2007, 129, 6688−6689. (23) Lv, K.; Lin, L.; Wang, X.; Zhang, L.; Guo, Y.; Lu, Z.; Liu, M. Significant Chiral Signal Amplification of Langmuir Monolayers Probed by Second Harmonic Generation. J. Phys. Chem. Lett. 2015, 6, 1719−1723. (24) Wang, J.; Ding, D.; Zeng, L.; Cao, Q.; He, Y.; Zhang, H. Transformation, Memorization and Amplification of Chirality in Cationic Co (III) Complex-Porphyrin Aggregates. New J. Chem. 2010, 34, 1394−1400. (25) Zhu, Y.; Xu, Y.; Zou, G.; Zhang, Q. Chirality Transfer and Modulation in LB Films Derived From the Diacetylene/Melamine Hydrogen-Bonded Complex. Chirality 2015, 27, 492−499. (26) Prins, L. J.; Huskens, J.; de Jong, F.; Timmerman, P.; Reinhoudt, D. N. Complete Asymmetric Induction of Supramolecular Chirality in a Hydrogen-Bonded Assembly. Nature 1999, 398, 498− 502. (27) Wang, T.; Liu, M. Langmuir-Schaefer Films of a Set of Achiral Amphiphilic Porphyrins: Aggregation and Supramolecular Chirality. Soft Matter 2008, 4, 775−783. (28) Liu, L.; Li, T.; Lee, M. Chiral Assemblies of Achiral RigidFlexible Molecules at the Air/Water Interface Induced by Silver (I) Coordination. ChemPhysChem 2012, 13, 578−582. (29) Yang, D.; Duan, P.; Zhang, L.; Liu, M. Chirality and Energy Transfer Amplified Circularly Polarized Luminescence in Composite Nanohelix. Nat. Commun. 2017, 8, 15727. (30) Liu, M.; Zhang, L.; Wang, T. Supramolecular Chirality in SelfAssembled Systems. Chem. Rev. 2015, 115, 7304−7397. (31) Onouchi, H.; Miyagawa, T.; Morino, K.; Yashima, E. Assisted Formation of Chiral Porphyrin Homoaggregates by an Induced Helical Poly (Phenylacetylene) Template and Their Chiral Memory. Angew. Chem. 2006, 118, 2441−2444. (32) Li, A.; Zhao, L.; Hao, J.; Ma, R.; An, Y.; Shi, L. Aggregation Behavior of the Template-Removed 5, 10, 15, 20-Tetrakis (4sulfonatophenyl) porphyrin Chiral Array Directed by Poly (ethylene glycol)-block-poly (l-lysine). Langmuir 2014, 30, 4797−4805. (33) Arteaga, O.; Canillas, A.; Crusats, J.; El-Hachemi, Z.; Llorens, J.; Sacristan, E.; Ribo, J. M. Emergence of Supramolecular Chirality by Flows. ChemPhysChem 2010, 11, 3511−3516.

AUTHOR INFORMATION

Corresponding Authors

*Y.G.: E-mail: [email protected]. *M.L.: E-mail: [email protected]. ORCID

Lu Lin: 0000-0003-1308-9158 Yuan Guo: 0000-0001-9644-0470 Minghua Liu: 0000-0002-6603-1251 Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS We thank the Natural Science Foundation of China (NSFC 21227802, 21503235, 21673251) and the Ministry of Science and Technology of China (MOST 2013CB834504) for financial support.

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REFERENCES

(1) Seo, J. S.; Whang, D.; Lee, H.; Jun, S. I.; Oh, J.; Jeon, Y. J.; Kim, K. A Homochiral Metal-Organic Porous Material for Enantioselective Separation and Catalysis. Nature 2000, 404, 982−986. (2) Nimri, S.; Keinan, E. Antibody-Metalloporphyrin Catalytic Assembly Mimics Natural Oxidation Enzymes. J. Am. Chem. Soc. 1999, 121, 8978−8982. (3) Cui, L.; Tokarz, D.; Cisek, R.; Ng, K. K.; Wang, F.; Chen, J.; Barzda, V.; Zheng, G. Organized Aggregation of Porphyrins in Lipid Bilayers for Third Harmonic Generation Microscopy. Angew. Chem., Int. Ed. 2015, 54, 13928−13932. (4) Esembeson, B.; Scimeca, M. L.; Michinobu, T.; Diederich, F.; Biaggio, I. A High-Optical Quality Supramolecular Assembly for Third-Order Integrated Nonlinear Optics. Adv. Mater. 2008, 20, 4584−4587. (5) Beels, M. T.; Fleischman, M. S.; Biaggio, I.; Breiten, B.; Jordan, M.; Diederich, F. Compact TCBD Based Molecules and Supramolecular Assemblies for Third-Order Nonlinear Optics. Opt. Mater. Express 2012, 2, 294−303. (6) Verbiest, T.; Van Elshocht, S.; Kauranen, M.; Hellemans, L.; Snauwaert, J.; Nuckolls, C.; Katz, T. J.; Persoons, A. Strong Enhancement of Nonlinear Optical Properties through Supramolecular Chirality. Science 1998, 282, 913−915. (7) Credi, A.; Balzani, V.; Langford, S. J.; Stoddart, J. F. Logic Operations at the Molecular Level. An XOR Gate Based on a Molecular Machine. J. Am. Chem. Soc. 1997, 119, 2679−2681. (8) Liu, C.; Yang, D.; Jin, Q.; Zhang, L.; Liu, M. A Chiroptical Logic Circuit Based on Self-Assembled Soft Materials Containing Amphiphilic Spiropyran. Adv. Mater. 2016, 28, 1644−1649. (9) Zhang, L.; Lu, Q.; Liu, M. Fabrication of Chiral LangmuirSchaefer Films from Achiral TPPS and Amphiphiles through the Adsorption at the Air/Water Interface. J. Phys. Chem. B 2003, 107, 2565−2569. (10) Huang, X.; Li, C.; Jiang, S.; Wang, X.; Zhang, B.; Liu, M. SelfAssembled Spiral Nanoarchitecture and Supramolecular Chirality in Langmuir-Blodgett Films of an Achiral Amphiphilic Barbituric Acid. J. Am. Chem. Soc. 2004, 126, 1322−1323. (11) Zhang, Y.; Chen, P.; Liu, M. A General Method for Constructing Optically Active Supramolecular Assemblies from Intrinsically Achiral Water-Insoluble Free-Base Porphyrins. Chem. Eur. J. 2008, 14, 1793−1803. (12) Shen, Z.; Wang, T.; Liu, M. Macroscopic Chirality of Supramolecular Gels Formed from Achiral Tris (ethyl cinnamate) Benzene-1, 3, 5-tricarboxamides. Angew. Chem., Int. Ed. 2014, 53, 13424−13428. (13) Liu, L.; Hong, D.-J.; Lee, M. Chiral Assembly from Achiral Rod-Coil Molecules Triggered by Compression at the Air-Water Interface. Langmuir 2009, 25, 5061−5067. F

DOI: 10.1021/acs.langmuir.7b04170 Langmuir XXXX, XXX, XXX−XXX

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Langmuir (34) D’Urso, A.; Randazzo, R.; Lo Faro, L.; Purrello, R. Vortexes and Nanoscale Chirality. Angew. Chem., Int. Ed. 2010, 49, 108−112. (35) De Feyter, S.; De Schryver, F. C. Two-Dimensional Supramolecular Self-Assembly Probed by Scanning Tunneling Microscopy. Chem. Soc. Rev. 2003, 32, 139−150. (36) Elemans, J. A.; De Cat, I.; Xu, H.; De Feyter, S. TwoDimensional Chirality at Liquid-Solid Interfaces. Chem. Soc. Rev. 2009, 38, 722−736. (37) Humblot, V.; Barlow, S. M.; Raval, R. Two-Dimensional Organisational Chirality through Supramolecular Assembly of Molecules at Metal Surfaces. Prog. Surf. Sci. 2004, 76, 1−19. (38) Gellman, A. J. Chiral Surfaces: Accomplishments and Challenges. ACS Nano 2010, 4, 5−10. (39) Benjamin, I. Mechanism and Dynamics of Ion Transfer. Science 1993, 261, 1558−1560. (40) Li, F.; Unwin, P. R. Scanning Electrochemical Microscopy (SECM) of Photoinduced Electron Transfer Kinetics at Liquid/ Liquid Interfaces. J. Phys. Chem. C 2015, 119, 4031−4043. (41) Watarai, H. What’s Happening at the Liquid-Liquid Interface in Solvent Extraction Chemistry? TrAC, Trends Anal. Chem. 1993, 12, 313−318. (42) Uchiyama, Y.; Kitamori, T.; Sawada, T.; Tsuyumoto, I. Role of the Liquid/Liquid Interface in a Phase-Transfer Catalytic Reaction as Investigated by in Situ Measurements Using the Quasi-Elastic Laser Scattering Method. Langmuir 2000, 16, 6597−6600. (43) Russell, J. T.; et al. Self-Assembly and Cross-Linking of Bionanoparticles at Liquid-Liquid Interfaces. Angew. Chem., Int. Ed. 2005, 44, 2420−2426. (44) Gu, H.; Yang, Z.; Gao, J.; Chang, C.; Xu, B. Heterodimers of Nanoparticles: Formation at a Liquid-Liquid Interface and ParticleSpecific Surface Modification by Functional Molecules. J. Am. Chem. Soc. 2005, 127, 34−35. (45) Binder, W. H. Supramolecular Assembly of Nanoparticles at Liquid-Liquid Interfaces. Angew. Chem., Int. Ed. 2005, 44, 5172−5175. (46) Lin, Y.; Skaff, H.; Emrick, T.; Dinsmore, A. D.; Russell, T. P. Nanoparticle Assembly and Transport at Liquid-Liquid Interfaces. Science 2003, 299, 226−229. (47) Watarai, H.; Adachi, K. Measuring the Optical Chirality of Molecular Aggregates at Liquid-Liquid Interfaces. Anal. Bioanal. Chem. 2009, 395, 1033−1046. (48) Takechi, H.; Canillas, A.; Ribó, J. M.; Watarai, H. Alignment and Chirality of Porphyrin J Aggregates Formed at the Liquid-Liquid Interface of a Centrifugal Liquid Membrane Cell. Langmuir 2013, 29, 7249−7256. (49) Takechi, H.; Adachi, K.; Monjushiro, H.; Watarai, H. Linear Dichroism of Zn (II)- Tetrapyridylporphine Aggregates Formed at the Toluene/Water Interface. Langmuir 2008, 24, 4722−4728. (50) Wada, S.; Fujiwara, K.; Monjushiro, H.; Watarai, H. Optical Chirality of Protonated Tetraphenylporphyrin J-Aggregate Formed at the Liquid-Liquid Interface in a Centrifugal Liquid Membrane Cell. J. Phys.: Condens. Matter 2007, 19, 375105. (51) Adachi, K.; Chayama, K.; Watarai, H. Formation of Helical Jaggregate of Chiral Thioether-Derivatized Phthalocyanine Bound by Palladium (II) at the Toluene/Water Interface. Langmuir 2006, 22, 1630−1639. (52) Adachi, K.; Chayama, K.; Watarai, H. Control of Optically Active Structure of Thioether-Phthalocyanine Aggregates by Chiral Pd (II)-BINAP Complexes in Toluene and at the Toluene/Water Interface. Chirality 2006, 18, 599−608. (53) Fujiwara, K.; Monjushiro, H.; Watarai, H. Nonlinear Optical Activity of Porphyrin Aggregate at the Liquid/Liquid Interface. Chem. Phys. Lett. 2004, 394, 349−353. (54) Yan, E. C. Y.; Fu, L.; Wang, Z.; Liu, W. Biological Macromolecules at Interfaces Probed by Chiral Vibrational Sum Frequency Generation Spectroscopy. Chem. Rev. 2014, 114, 8471− 8498. (55) Haupert, L. M.; Simpson, G. J. Chirality in Nonlinear Optics. Annu. Rev. Phys. Chem. 2009, 60, 345−365.

(56) Sioncke, S.; Verbiest, T.; Persoons, A. Second-Order Nonlinear Optical Properties of Chiral Materials. Mater. Sci. Eng., R 2003, 42, 115−155. (57) Lin, L.; Wang, T.; Lu, Z.; Liu, M.; Guo, Y. In Situ Measurement of the Supramolecular Chirality in the Langmuir Monolayers of Achiral Porphyrins at the Air/Aqueous Interface by Second Harmonic Generation Linear Dichroism. J. Phys. Chem. C 2014, 118, 6726− 6733. (58) Lin, L.; Liu, A.; Guo, Y. Heterochiral Domain Formation in Homochiral α-Dipalmitoylphosphatidylcholine (DPPC) Langmuir Monolayers at the Air/Water Interface. J. Phys. Chem. C 2012, 116, 14863−14872. (59) Xu, Y.-y.; Rao, Y.; Zheng, D.-s.; Guo, Y.; Liu, M.-h.; Wang, H.-f. Inhomogeneous and Spontaneous Formation of Chirality in the Langmuir Monolayer of Achiral Molecules at the Air/Water Interface Probed by in Situ Surface Second Harmonic Generation Linear Dichroism. J. Phys. Chem. C 2009, 113, 4088−4098. (60) Martin-Gassin, G.; Benichou, E.; Bachelier, G.; RussierAntoine, I.; Jonin, C.; Brevet, P.-F. Compression Induced Chirality in Dense Molecular Films at the Air-Water Interface Probed by Second Harmonic Generation. J. Phys. Chem. C 2008, 112, 12958− 12965. (61) Verbiest, T.; Kauranen, M.; Maki, J. J.; Teerenstra, M.; Schouten, A.; Nolte, R.; Persoons, A. Linearly Polarized Probes of Surface Chirality. J. Chem. Phys. 1995, 103, 8296−8298. (62) Petralli-Mallow, T.; Wong, T.; Byers, J.; Yee, H.; Hicks, J. Circular Dichroism Spectroscopy at Interfaces: A Surface Second Harmonic Generation Study. J. Phys. Chem. 1993, 97, 1383−1388. (63) Simpson, G. J. Structural Origins of Circular Dichroism in Surface Second Harmonic Generation. J. Chem. Phys. 2002, 117, 3398−3410. (64) Wang, J.; Chen, X.; Clarke, M. L.; Chen, Z. Detection of Chiral Sum Frequency Generation Vibrational Spectra of Proteins and Peptides at Interfaces in Situ. Proc. Natl. Acad. Sci. U. S. A. 2005, 102, 4978−4983. (65) Fu, L.; Zhang, Y.; Wei, Z.-H.; Wang, H.-F. Intrinsic Chirality and Prochirality at Air/R-(+)-and S-(−)-Limonene Interfaces: Spectral Signatures with Interference Chiral Sum-Frequency Generation Vibrational Spectroscopy. Chirality 2014, 26, 509−520. (66) Wei, F.; Xu, Y.-y.; Guo, Y.; Liu, S.-l.; Wang, H.-f Quantitative Surface Chirality Detection with Sum Frequency Generation Vibrational Spectroscopy: Twin Polarization Angle Approach. Chin. J. Chem. Phys. 2009, 22, 592−600. (67) Maki, J. J.; Verbiest, T.; Kauranen, M.; Elshocht, S. V.; Persoons, A. Comparison of Linearly and Circularly Polarized Probes of Second-Order Optical Activity of Chiral Surfaces. J. Chem. Phys. 1996, 105, 767−772. (68) Svechkarev, D.; Kolodezny, D.; Mosquera-Vázquez, S.; Vauthey, E. Complementary Surface Second Harmonic Generation and Molecular Dynamics Investigation of the Orientation of Organic Dyes at a Liquid/Liquid Interface. Langmuir 2014, 30, 13869−13876. (69) Watry, M. R.; Richmond, G. L. Orientation and Conformation of Amino Acids in Monolayers Adsorbed at an Oil/Water Interface as Determined by Vibrational Sum-Frequency Spectroscopy. J. Phys. Chem. B 2002, 106, 12517−12523. (70) Higgins, D. A.; Naujok, R. R.; Corn, R. M. Second Harmonic Generation Measurements of Molecular Orientation and Coadsorption at the Interface between Two Immiscible Electrolyte Solutions. Chem. Phys. Lett. 1993, 213, 485−490. (71) Grubb, S.; Kim, M. W.; Rasing, T.; Shen, Y. Orientation of Molecular Monolayers at the Liquid-Liquid Interface as Studied by Optical Second Harmonic Generation. Langmuir 1988, 4, 452−454. (72) Naujok, R. R.; Higgins, D. A.; Hanken, D. G.; Com, R. M. Optical Second-Harmonic Generation Measurements of Molecular Adsorption and Orientation at the Liquid/Liquid Electrochemical Interface. J. Chem. Soc., Faraday Trans. 1995, 91, 1411−1420. (73) Perrenoud-Rinuy, J.; Brevet, P.-F.; Girault, H. H. Second Harmonic Generation Study of Myoglobin and Hemoglobin and G

DOI: 10.1021/acs.langmuir.7b04170 Langmuir XXXX, XXX, XXX−XXX

Article

Langmuir Their Protoporphyrin IX Chromophore at the Water/1, 2-Dichloroethane Interface. Phys. Chem. Chem. Phys. 2002, 4, 4774−4781. (74) Licari, G.; Brevet, P.-F.; Vauthey, E. Fluorescent DNA Probes at Liquid/Liquid Interfaces Studied by Surface Second Harmonic Generation. Phys. Chem. Chem. Phys. 2016, 18, 2981−2992. (75) Wang, X. Y.; Li, L.; Lin, L.; Zhang, Z.; Lu, Z.; Liu, M. H.; Guo, Y. Chiral Transformation of PARC18 Assemblies on NaOH Solution Subphase. Spectrosc. Spect. Anal. 2016, 36, 47−50. (76) Liu, M.; Ushida, K.; Nakahara, H.; Kira, A. Novel Photorecording Langmuir-Blodgett Films. Adv. Mater. 1997, 9, 1099−1101. (77) Liu, M.; Ushida, K.; Kira, A.; Nakahara, H. Complex Formation between Amphiphilic Organic Ligands and Transition Metal Ions in Monolayers and LB Multilayers. Thin Solid Films 1998, 327, 491− 494. (78) Verbiest, T.; Kauranen, M.; van Rompaey, Y.; Persoons, A. Optical Activity of Anisotropic Achiral Surfaces. Phys. Rev. Lett. 1996, 77, 1456−1459. (79) Verbiest, T.; Kauranen, M.; Persoons, A. Optical Activity of Anisotropic Achiral Surfaces. J. Opt. Soc. Am. B 1998, 15, 451−457. (80) Eisenthal, K. B. Liquid Interfaces Probed by Second-Harmonic and Sum-Frequency Spectroscopy. Chem. Rev. 1996, 96, 1343−1360. (81) Wei, F.; Ye, S. Molecular-Level Insights into N-N π-Bond Rotation in the pH-Induced Interfacial Isomerization of 5Octadecyloxy-2-(2-pyridylazo) phenol Monolayer Investigated by Sum Frequency Generation Vibrational Spectroscopy. J. Phys. Chem. C 2012, 116, 16553−16560. (82) Rao, Y.; Tao, Y.-S.; Zheng, D.-s.; Wang, H.-f. New Phenomena in Phase Transition and Accurate Determination of Orientational Order in Langmuir Monolayer. Optical Science and Technology, SPIE’s 48th Annual Meeting, 2003; pp 177−186. (83) Moad, A. J.; Simpson, G. J. A Unified Treatment of Selection Rules and Symmetry Relations for Sum-Frequency and Second Harmonic Spectroscopies. J. Phys. Chem. B 2004, 108, 3548−3562. (84) Burke, B. J.; Moad, A. J.; Polizzi, M. A.; Simpson, G. J. Experimental Confirmation of the Importance of Orientation in the Anomalous Chiral Sensitivity of Second Harmonic Generation. J. Am. Chem. Soc. 2003, 125, 9111−9115. (85) Zhang, Z.; Guo, Y.; Lu, Z.; Velarde, L.; Wang, H.-f. Resolving Two Closely Overlapping- CN Vibrations and Structure in the Langmuir Monolayer of the Long-Chain Nonadecanenitrile by Polarization Sum Frequency Generation Vibrational Spectroscopy. J. Phys. Chem. C 2012, 116, 2976−2987. (86) Nandi, N.; Vollhardt, D. Effect of Molecular Chirality on the Morphology of Biomimetic Langmuir Monolayers. Chem. Rev. 2003, 103, 4033−4076. (87) Xu, Y.-y. Investigation of Molecular Chirality and Orientation by in-Situ Optical Second Harmonic Generation. Ph.D. Thesis, Institute of Chemistry, Chinese Academy of Sciences, 2009.

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DOI: 10.1021/acs.langmuir.7b04170 Langmuir XXXX, XXX, XXX−XXX