Self-Assembled Chiral Nanoparticle Superstructures and Identification

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Self-Assembled Chiral Nanoparticles Superstructures and Identification of Their Collective Optical Activity from Ligand Asymmetry Xiang Mao, Zhenyu Wang, Deping Zeng, Hua Cao, Yang Zhan, Yang Wang, Qifeng Li, Yongtao Shen, and Jiefu Wang ACS Nano, Just Accepted Manuscript • Publication Date (Web): 08 Mar 2019 Downloaded from http://pubs.acs.org on March 8, 2019

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Self-Assembled Superstructures

Chiral and

Identification

Nanoparticles of

Their

Collective Optical Activity from Ligand Asymmetry Xiang Mao, ‡* Zhenyu Wang, ‡ Deping Zeng, ‡ Hua Cao, ‡ Yang Zhan, † Yang Wang, § Qifeng Li, §* Yongtao Shen,∥* and Jiefu Wang†*

†. Department of Colorectal Cancer, Tianjin Medical University, Cancer Institute and Hospital (National Clinical Research Center for Cancer), Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300072 (P. R. China).

‡. State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and MOST, College of Biomedical Engineering, Chongqing Medical University, Chongqing, 400016, (P. R. China).

ACS Paragon Plus Environment

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§. School of Precision Instrument and Opto-electronics Engineering, Tianjin University, Tianjin 300072, (P. R. China).

∥. Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin 300072, (P. R. China).

*E-mail: (J. W) [email protected]; (X. M.) [email protected]; (Q. L) [email protected]; (Y. Sh.) [email protected]

ABSTRACT: Spontaneous self-assembly of chiral nanoparticles (NPs) into stationary fabrication has be well interested in technique investigation and science advancement due to its expected apparent properties via orderly collective behaviors. However, this kind of characterization of assembled nanoparticles superstructure (NPS) is rarely report, and which is distinguished with mono-dispersed chiral NPs. In this work, we used L-cysteine (Cys) as the chiral molecule in form of functional surfactant, which was capped CdS/CdTe NPs and treated as linkage bridges for constructing orderly assembled NPS. Among in circular dichrosim (CD) phenomenon, Cys ligands exhibit


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related changes in CD absorption while whole molecules solution is treating in different pH controlling procedures. Synthesized chiral NPs are organized into ordered rodshaped NPS during spontaneous self-assembly process, the CD response of NPS is monitored while in different cultivating times, and it showed a persuasive response appears in sum frequency generation (SFG) spectroscopy. Both of experimental works and theory calculation convey that the ordered stacking of chiral stabilizer and the chirality of NPS, which are identified from chiral molecular status and their collective optical activity originated from ligand asymmetry.

KEYWORDS: chirality; self-assembling; superstructures (SPs); circular dichrosim (CD) spectra; sum frequency generation (SFG)

Chiral nanoparticles (NPs) have attracted particularly interest in the fields of asymmetry amplification in form of chiral catalysts, membrane science and dopant in liquid crystals and so on, which has great importance for the developed nanosystems.1-5 Among in previous investigations, it shows the attractive phenomenon while chiral fabrication is characterized in visible range, Appeared in previous works,

chiral


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molecules mainly exhibit obvious circular dichroism (CD) response in the ultraviolet range and showed the weak response at visible range, this optical activity were well utilized in form of designed device application.6-9 Among in these researches, chiral superstructures (SPs) were well built and showed various related properties during spontaneous self-assembled procedures,

the desired ordered SPs architectures

convey the revolutions in fabricating functional materials too. From synthetic approaches, the intrinsic physical characteristics of assembled chiral SPs can be attributed to their nanometer-sized building blocks in solvent mediums under different reactant condition as well as coupling effect.10-12 These SPs are emerged as a powerful paradigm for designing and fabricating functional materials toward the researches’ clues for applications and shows either a short- or long-range ordered construction. Especially increasing or decreasing the change in dimension of chiral construction, the ordered structures are more easily to understand its chirality and how the mechanisms operation while compared with low dimension chiral materials. Some of researches are still keep exploiting in various dimensions under different experimental conditions. Among in different SPs, there are different sorts and conclusions for the identification of whole CD


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response. The essential of these works are tracking the CD response, the difference between low dimension chiral NPs and their chiral SPs. There have the obvious difference while one chiral unit such as signal particle in properties’ characterizations between nano/ micro-scale fabrications. The observed chirality can be attributed to the collection of optical activity from ligand asymmetry, which is considerable to investigated collective chirality of SPs.

In order to illustrate the correspondence of individual chiral molecules attribution in whole fabricated constructions, in which, molecular systems show mostly strong chirality in the UV spectral range. As in examples, pure surfactants such as DNA, chiral protein, and other chiral molecules have the CD bands in the range of 150–300 nm, the mechanisms of these optical activities in NPs and their SPs cannot be easily identified about chirality recognition. It was also demonstrated that NPs show very broad band between 370 and 710 nm with the maximum wavelength in the range of 485–505 nm in CD spectra, which can be ascribed to size-increasing and defects or trap states on the surfaces of the NPs. The collective chirality will be confused in the broaden CD peak of


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NPS. Therefore, there have not efficient approaches to evaluate the bulk construction, in which, chirality and chiral inducement function should be well understood and provide the foreseeable tool to construction states. Thus, the identification of collective chirality toward SPs is still one significant field in understanding the CD recognition and absorption response from various chiral constructions. Sum frequency generation (SFG) spectroscopy has been established as a efficient tool for investigating bulk chiral researches in this paper.13, 14

Scheme 1. Synthetic mono-dispersed CdS/CdTe nanoparticles (NPs) and selfassembling procedures of chiral superstructure (SPs).

RESULTS AND DISCUSSION


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The chiral response from the bulk constructions was considered as the origination from the intrinsic chirality of the chiral candidates. Without electronic resonance, chiral SFG is surface-specific with sub-monolayer sensitivity for surface chirality probing.15 Here, we investigated the self-assembled rod-shaped chiral SPs for follow two reasons in principle: (1) the optical absorption response of chiral substances in different solution environments, the chirality is adjusted in whole mediums, in which , the chiral response is arised from the chiral surfactants, organic materials, or chiral intermediate products, which gives the rise to different kinds chiral SPs;16 (2) collected interactions between chiral NPs and 3D ordered SPs, the related simulation of self-assemble activity reflected the chiral response is raised from chiral molecules accumulation-induced effect, which is different with the bulk constructions, the chirality from the surface can also origin from the chiral spatial arrangements of achiral molecular according to previous theory expanding.17 Based on above point of departure, we try to design and prepared the chiral NPs and SPs for deeply investigation, the optical CD response could be monitored and then be easily influenced before and after self-assembling procedures. Lcysteine (Cys) is used as the chiral both of surfactant and reducer in synthesis mono-


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dispersed CdS/CdTe NPs and their SPs together. And then, the original CD optical response and SFG methods were used to characterize the collection and non-collection chirality of nanoparticle and self-assembled SPs, respectively. Chiral SFG has been widely used for recognizing surface chirality of biomolecules.18-20 I It will greatly contribute to the researches of nanoscale chirality. The ordered SPs are synthesized by the method of hydrothermal reaction,24-27 and the full procedure can be realized as showed in scheme 1. In main chemical and real mechanisms, the chirality origin from the spatial arrangements is regarded as their collective optical activity from ligand asymmetry phenomenon. 21-23


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Figure 1. a) TEM images of rod-shaped superstructures (SPs). b) SEM images of rodshaped SPs. c) HR-TEM image of the terminal of the rod-shaped SPs. The inset image in b) is the selected area electron diffraction (SAED) patterns. d) Energy dispersive spectroscopy (EDS) of rod-shaped SPs.

The typical transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of Cys capped SPs are shown in Figures 1(a) and Figure 1(b), respectively. The rod-shaped SPs are considered as high dimensional


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construction, and it was well constructed in water solvent medium under different cultivating atmospheres. From images exhibition, as appeared end of rod SPs, there has rough surface and the crystal morphology like as wedge tips which can be ascribed to the spontaneous procedure, Especially in the whole assembling processes, the medium environment is one of key points in influencing chiral molecules functions with different functional groups and making essential linkage between different precursors or resulted NPs. In self-assembling process, the generally reducing the amount of Cys per particle in a net characterization which can decrease the charge repulsion and increase the possibility of particles' attraction energy such as fcc accumulation, which induces the individual particle's self-assembly action. In spontaneous assemble process, Cys should be cross-linked with metal ions in aqueous and considered similar as the coordination procedure, that is effected by various medium atmosphere. In chiral candidate synthetic work, Cys could dissociate in negative charge system, it appears the same phenomenon for the anion sulfur integrating with original systems. It has report mentioned about S2- can be released into CdTe NPs and the Te element can be replaced by S while the mechanism of this replacement was proved and realized.28 As a


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result of the considerable loss of the Te, the primary CdTe NPs is gradually transformed and finally comes to CdTe / CdS SPs through the spontaneous self-assembly approach. The rod-shaped SPs are composed of individual NPs as shown by the HRTEM images (Figure 1c). From this, we can clearly observe that the superstructure is composed of individual NPs. The inset of Figure 1(c) the SAED pattern of the bundle structures also gives evidence to the composite of the SPs. Three characteristic diffraction patterns for the most bright three circles are respectively (d = 0.32 nm), (d = 0.19 nm), and (d = 0.17 nm), and these do not match any stable CdS and CdTe crystal structures.29 it is well correspond with elemental replacement in synthetic procedure and proved the doped CdS/CdTe NPs is obtained. Energy dispersive spectroscopy reveals the composition of the rod-like superstructure, and the atomic Cd : Te : S ratio was 48.7 : 1.7: 49.6, as shown in Figure 1(D) and shows the phase of CdS is dominant constitution in final construction. Undergoing different solution environment, the –C-S-Cd could be transfer to C-S-H and Cd2+, thus the 3D ordered SPs can be obtained. This charge repulsion lead to the face-face attractive accumulation, which induces the self-assembled construction finished and showed higher dimensional features.


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Figure 2. CdS/CdTe superstructures (SPs) analysis under different condition, a) Aggregated NPs into rod morphology, the inset image is mono-dispersed NPs at present period in self-assembling process, b) Obtained SPs and intermediated product, c) Assembled CdS/CdTe SPs and d) Tips' area morphology.

The synthetic CdS/CdTe nanoparticles and assembled intermediate product are characterized as showed in Figure 2. It clearly observes that the mono-dispersed NPs


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at present period in self-assemble process, and the aggregated units as showed in Figure 2a, which implied the fabricated final construction showed it is consisted of individual CdS/CdTe nanoparticles and it can be attributed to S replacing Te in the SPs and enhanced the between each of NPs. In which, it conveys that chemical reaction is accompanied by the assembly process, it appears that small units aggregated and among in growth process. With reacted time increasing, mono-dispersed CdS/CdTe nanoparticle synthesized in water solvent medium by following the Ostwald ripening principle, and the fluorescence property as shown in Figure S1. Among in different growth time, the intermediate structure and self-constructed SPs, both of these product can be monitored and the self-assembling structure is formed during in this spontaneous procedure (Figure 2b). In order to understand the structure of SPs detail, a discovery at SPs' tip crystalline observation, it showed the individual particle with several layers (Figure 2c, 2d). Particularly, due to the existence of amount of the organic capping agents around the inorganic CdS/CdTe nanoparticles, it is of feasibility to get stable dispersing NPs colloid in alkaline condition. However, this stable tendency is just contrary to our goal to generate the process of self-assembly, in which, the SPs


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are constructed via individual nanoparticle.30-32 In this aqueous system, the process of transformation from individual nanoparticle to SPs will be modulated through control the capping agents on NPs, which is mainly influenced by the solution atmosphere such as pH value and adjusting the competitive relation between repulsion and attractions. By considering about the duplicate characterization (three times) of this self-assemble processes, there have not attractive influence while the mono-dispersed NPs were kept at same cultivated atmosphere. Especially among resultant products, the rod-shaped SPs can be well established and tips of these structures have less sharp area, which can be ascribed to individual particle aggregated naturally because it rod-shaped SPs implied the higher energy distribution than middle part.


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Figure 3. SEM images of self-assembled SPs while duplicate characterized three times, first time (a, b, c); second time (d, e, f); third time (g, h, i), respectively.

By considering more details of the chiral SPs, there are two possible models can be assumed in the growth of SPs: one is achiral surface is absorbed by chiral networks which is fabricated through chiral molecule cross linking approach; another type is achiral surface integrated with chiral molecule forming chiral SPs.33-35 Chiral molecule and achiral NPs are separated, which implies two speculations make big difference in


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bonds on their surface. In order to certain the structure, the infrared spectra (IR) is performed, which demonstrates that all surfactant molecules are capping on the inorganic core by –S-Cd- bonds. IR results of SPs and pure Cys (Figure S2), it conveys typical functional groups (carboxyl group,-COOH, the IR absorption broad bands around 2500–3200cm-1 (νO–H), 1250 cm-1(δOH-), –NH3+ (δsNH3+: 1588 cm-1, δasNH3+ : 1530cm-1) and –SH (νS–H: 2550 cm-1) are observed on Cys as shown in black line, while those groups characteristic peaks disappear on the red line. Instead of them, –COO- (1599 cm-1) and NH2 (νN–H: 3428 cm-1) are found on the surface of the SPs. As reported, due to the formation of covalent bonds between thiols similar as carboxyls captured the Cd2+ ions on the surface of achiral NPs, the peak of –SH and –COOH groups disappeared after crosslink reaction procedures, it proves that the pure Cys molecule is not existent and the SPs are formed by the NP with Cys as much as possible.

To answer those chiral questions above, we did the investigation of CD absorption response of mono-dispersed NPs and SPs in the visible-light region. As an indispensable supplement, chiral molecule shows surfactant dissociated phenomenon


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in alkaline atmosphere by adjusting pH conditions, which is a considerable factor that effects on the stability of colloid solution and spontaneous self-assembly process. By considering the inchoative period of synthetic process, the comparison between in optical properties of pure Cys and Cdx(Cys)y complexes in the aspects of the CD and UV spectrogram is one necessary achievement for further understanding.36, 37 As shown in Figure S3, Cys and Cdx(Cys)y complexes contribute CD absorption response nearby 260 nm, which is consistent with UV spectra. Compared with pure Cys, there is an obvious change in CD signals, with an additional peak appearing at about 240 nm for Cdx(Cys)y complexes at different pH values (9, 10, 11.3). Among in different pH values, there is a clear negative peak at range from 240 nm to 300 nm in CD signals of Cdx(Cys)y, which might be attribute to the –S-Cd- complexes and induced chirality enhancement. Here, only the broad degree is different, the Cdx(Cys)y complexes and appreciable quantity thiol group (–SH) existing, the peak is board from 240 nm to 320 nm while pH value is adjusting at 9.0 Additionally, Cdx(Cys)y complexes and less -SH existing and the peak is sharp at the 240 nm in CD spectra while pH value is adjusted at 11.3. It provides the direct evidence for monitoring the functional group forming


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coordination construction and functional chiral group enhances assembling process simultaneously for making high dimensional SPs. It benefits to analyze the CD spectrum of synthetic process of individual NPs and 3D-ordered SPs.

Figure 4. (a, b, c, d, e, f) CD spectra (red) and corresponding UV/Vis spectra (black) of self-assembling time dependent (1h, 29h, 172h) SPs at pH=9, 11.3 values, respectively.

Figure 4 and Figure S4 are the dynamical CD spectrum details at different pH values, and it reveals self-assembling process while whole system is undergoing different time.


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It expresses the UV/Vis and CD spectrum of SPs at different pH values while cultivating during different time. More interestingly, Cys stabilized CdS/CdTe NPs characteristic CD absorption peaks in the range of 300–700 nm exhibit gradual change when the selfassembling of SPs increasing along with the time elapsing. It showed the distinct observation of final self-assembled SPs were initially fabricated and cultivated at pH=9 and 11.3, respectively. There have not any changes observed in the window while SPs is treated pH=11.3, which can be ascribed to the self-assembling process is not happened, and there have no SPs appeared in whole medium systems.

By well

dissolved chiral NPs under pH = 11.3 condition, it noted that the colloidal solution keeps high stability even its pH value is adjusted to higher alkaline atmosphere, and which can be ascribed to the strong repulsion in solvent medium. Observed CD spectrum from 200 nm to 300 nm, which can be attributed to the quantum confinement effect of NPs cores, in which, UV adsorption is from 200 nm to 300 nm along with the first excitonic absorption bands. On the contrary, the reasonable CD absorption peak appeared at range from 400nm to 500nm after 172 hours consuming under pH=9.0 treatment. This self-assembling procedure gives high ordered and broad absorption peak in CD


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response measurements, it can be attributed to self-assembling process of NPs and circular polarized light scattering phenomenon. Along with the cultivating time increasing, size dependent influence in CD response reflects the spontaneous assembling proceed of chiral SPs in UV/Vis range, but also it proved the formation and its scale of chiral construction from the side views. It is unavoidable to ignore the size scatter effect in identifying the optical properties while measuring chiral absorption. The gradually emergent broaden peak at CD spectrum is characteristic in chirality inducement, which would be attributed to defects or trap states on the surfaces of NPs. Therefore, it is hard to identify the size increasing effect, the surface state and the collective chirality of SPs by chiral CD measurement.


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Figure 5. Molecular structure of Cys stabilizers at the CdS/CdTe NPs surface. 1H NMR spectra of (a) Cys in D2O, (b) Cdx(Cys)y complexes in D2O, (c) SPs in D2O and (d) Two-dimensional 1H–1H NOESY spectrum of SPs, respectively.

Among the previous researches, there have reference reported the recognition its structure information by using NMR characterization.38-41 The Cys surface ligands are bonding to the surface of CdS/CdTe NPs surface via Cd2+ ions as shown in Figure 5.


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The hydrogen atoms bonding with chiral carbon and methylene of Cys are indicated by a single-letter code: chiral, α; methylene, β. The space relations are marked by red and blue arrows as shown in Figure 5. In order to research the Cys surface ligands on nanoparticles surface, we studied this ligands bonding by 1H and 1H-1H NOESY NMR spectroscopy using a 400 MHz spectrometer. Firstly, as a control experiment, the 1H NMR spectra of Cys and Cdx(Cys)y complexes revealed that the chiral hydrogen atoms (α) and the methylene hydrogen atoms (β) resonances of Cys shift to higher frequency as compared to un-conjugated Cys (Figure 5 a, b). 1H NMR spectra of NPs showed four different peaks. According to the 1H-1H NOESY results, the lowest peak (0.85 ppm) has not any space relations with other three peaks and the chemical shift is very low (0.85 ppm) as shown in Figure S5 and 5c. We think these part alkane hydrogen atoms are attributed to the desulphurized Cys, which also demonstrated the ligands would fall away from nanoparticles in the self-assembly process. Other three kinds of hydrogen atoms (3.38 ppm, 2.87 ppm, 2.68 ppm, 1:1:1) are very interesting, as if they are belong to three different types of hydrogen atoms. But, in NOESY results, we found the (α) peak is related to β1 and β2 peaks in space as directed by red arrows. So we think the α


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peak is belong to two kinds of chiral hydrogen atoms (α1+α2). The ratio of α1+α2 : β1: β2 atoms are about 1+1 : 2 : 2, which illustrated that the mounts of two types of Cys on the nanoparticles are same. Additionally, the β1 and β2 hydrogen atoms are related to each other in space as marked by blue arrows in Figure 5d. These results illustrated that there are two types of distinct coordination geometries for Cys bonding with Cd2+ on the NPs’ surface and they are well-distributed arrangement. So we hypothesize that the Cd2+ are distributed as checkerboard or A-B parallel arrangement structures on the surface of NPs, which can well demonstrated in further works.

As was stated above, it is hard to identify the size increasing effect, the surface state and the collective chirality of SPs by chiral CD measurement. Thus we make use of sum frequency generation (SFG) method to simulate as one useful method to detect the collective chirality from self-assembled SPs.42-44 As showed in Figure 6, it has big difference while chiral superstructure and monodisperse nanoparticles evaluated in SFG measurement as shown below. The chiral SFG signals only come from the collective chirality of CdS/CdTe SPs. The SFG chiral response is given by the coherent


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summation of all the contributions from each monomer, which is mathematically equivalent to an orientational average in simulated equation. Chirality in the SPs ensemble can still arise through orientational considerations, even without the intrinsic chirality. The nanoparticles can generate surface specific chiral SFG signal when arranged in collective chiral architecture, that associated with the chiral orientational arrangement of superstructure. Thus, the collective chirality of CdS/CdTe SPs should be originated from the high ordered arrangement of chiral NPs as shown in Figure 6a. But in the control experiment, the signal of collective chiral cannot be identified in monodisperse nanoparticles by the SFG as shown in Figure 6 (b). Taken together, it noted that the chiral vibrational SFG can be used to characterize and recognize the collective chirality of SPs.

The chiral SFG vibrational spectra in the range from 2700 cm-1 to 3300 cm-1 of the Cys stabilized CdS/CdTe NPS was presented in Figure 6 (a). The chiral SFG shows two band groups around 2900 cm-1 and 3000 cm-1, which can be assigned to CH2 symmetric and asymmetric stretch vibrational bond, respectively. The SFG band group


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is identical to the peaks in the FTIR spectrum at 2900 cm-1 and 3000 cm-1. In contrast, it does not show any signal in the chiral SFG spectra of Cys at the single NPs interface. We used PSP (P-polarized SFG, S-polarized visible, and P-polarized infrared) polarization for the acquisition of chiral SFG spectra. The SPs precipitate products were drop-wise added on the silicon substrate directly. Single NP samples were prepared by deposited on the silicon substrate repeatedly of NPs pH=11.3 solutions (About 1 ml). We could not detectany chiral SFG signal from single NPs, suggesting that Cys at the single NPs interface cannot generateany chiral CH2 stretch signal under our experimental conditions as shown in Figure 6. From Equation (3), the chiral SFG signal come from two kinds of origin: (1) intrinsic chiral β, I, j, k (i≠ j≠ k) and (2) orientational chirality. The silent chiral SFG signal means that both chiral origin are negligible. Firstly, the intrinsic chirality of Cys at the single NPs interface cannot be detectable by SFG. Secondly, negligible orientational chirality indicates Cys at the single NPs interface are random aligned that should be introduced by a largely disordered structureof the single NPs. Moreover, We would like argue that the obvious chiral SFG signals that we observe d originate from Cys at the stabilized CdS/CdTe SPs interface due to the high


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ordered chiral structure. The strong chiral signals is not likely from the bulk, because we adopts the SFG measurement in a reﬂective geometry without electronic resonance. The intrinsic chiral signal also can be negligible, considering the intrinsic chiral β: ijk (i ≠ j ≠ k) of Cys have the same value at the NPs interface. Hence, the chiral SFG signals only comes from the orientational chirality of Cys at the stabilized CdS/CdTe SPs interface. The SFG measurements in the laboratory frame are performed on ensembles of many NPs. The SFG chiral response is given by the coherent summation of all the contributions from each monomer, which is mathematically equivalent to an orientational average in Equation (4). Chirality in the SPs ensemble can still arise through orientational considerations, even without the intrinsic chirality. The Cys at the NPs interface can generate surface specific chiral SFG signal when arranged in macromolecular chiral architectures, that associated with the chiral orientational arrangement of NPs. Thus, the collective chirality of CdS/CdTe SPs should originate from the high ordered chiral arrangement of the NPs. Taken together, our results identify the chiral vibrational SFG can be used to characterize the collective chirality of nanoparticles SPs.


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Figure 6. a, b) SFG (PSP) spectra of Cys modified on Chiral CdS/CdTe SPs and monodisperse chiral CdS/CdTe nanoparticles on interface. Inset (a, c) structure model of sefl-assembled 3D ordered SPs and monodisperse chiral NPs.

CONCLUSIONS

In summary, we use the Cys as the ligand to synthesize chiral CdS/CdTe NPs and their rod-shaped SPs by using self-assembling approach in less alkaline aqueous mediums. Among in mono-dispersed NPs and assembled SPs, the chirality distinguishment is performed in different aqueous atmosphere by cultivating time consume. The original CD response from chiral molecule illustrates that the selfassembled SPs imply the collective chirality can be well affected in different status in aqueous medium. Attribute the success to evaluated approach by using SFG


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measurement in order to detect the single and collection chirality of SPs and single chiral particle. Combining with CD spectrum and SFG measurement, it identified that the chirality of rod-shaped superstructure is from ligand chirality inducement and the collective optical activity from ligand asymmetry. It expected that design and fully utilization in accurated chiral structure and specific optical properties, will give one comprehensible clue in spontaneous self-assembly field.

METHODS AND EXPERIMENTAL

Materials: Cadmium Chloride (CrCl2, 99.999%, Alfa Aesar), L-Cysteine (99.999%,Alfa Aesar), NaCl (90% tech.), HCl (80-90%, Alfa Aesar), Sodium Citrate (99.9%, SigmaAldrich), Bismuth Telluride (99%, Energy Chemical), are used directly without further purification. Synthesis of Chiral Nanoparticles (NPs): All raw materials used were of analytical grade or the highest purity available. In a typical synthesis, 0.4 mmol of CdCl2 and 0.6mmol of Cys were mixed in a 100 mL solution with 100 mg sodium citrate, and the pH value of the solution is adjusted to 11.3 by dropwise addition of 1.0 M NaOH solution


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with stirring. The solution was placed in a three-necked flask and air was replaced with Ar. Under stirring, freshly prepared NaHTe solution (0.3 mmol) is added through a syringe into the Cd precursor solution at room temperature. Then the reaction mixture was heated to reflux with a condenser attached in an oil bath at 100°C, which was protected by 99.9 % Ar conditions. It took 8 hours to finish the whole reaction, which timing started when the temperature was up to100°C. NPs were precipitated by the addition of methanol and centrifuged by high-speed centrifuge are dissolved in deionized water at pH=9.0.

Growth of Chiral NPs-NPs Superstructure (SPs): When the reaction was cooled to the room temperature naturally with the Ar condition protecting, in order to remove extra chromium and Cys complex, the SPs were precipitated by addition of three times methanol in the system and centrifuged under 10000r/min with 5 min. The precipitates were completely dissolved indeionized water at pH=9, 10, 11.3, which was adjusted by the addition of 1M NaOH aq. The samples are put in dark conditions for at least one week. Accompanied by the pass of time, it could be observed that white precipitates


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were generated gradually in the solution, the process is called as the self-assembling processes and the precipitate product is the ordered SPs.

Characterization Methods: UV-Vis absorption spectra were recorded in a range of 200-800 nm by using an Evolution 220 spectrophotometer in absorbance mode. The photoluminescence spectra and PLQY were obtained by a FLUOROMAX-4 spectrofluorometer equipped with a Xenon lamp. Its PL lifetime measurements can be carried out by using the HORTB-FM-2015 spectrofluorometer and fitted with a triexponential decay. CD spectra were measured using a JASCO J-815 CD spectrometer with a bandwidth of 1.0 nm. CD spectra of gels were recorded in the UV region (200-800 nm) using a 0.1 mm quartz cuvette at room temperature. TEM images and Energy dispersive spectroscopy (EDS) were collected by a TECNAI G2 F20 transmission electron microscope with an accelerating voltage 200 kV and a Gatan SC200 CCD camera. FT-IR spectra data was recorded with a Bruker Vertex 70 spectrometer in the range from 4000 to 500 cm-1. NMR: 1H and 1H-1H NOESY NMR spectroscopy using a Bruker AVANCE Ⅲ HD 400 MHz spectrometer.


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SFG Experimental Measurement: In this paper, a heterodyne-detected sum frequency generation (HD-SFG), which based on a femtosecond Ti-sapphire laser (120 fs, 800 nm,1 kHz and 2 mJ/pulse), is used to detect the chirality of the Cys stabilized CdTe/CdS NPs. The femtosecond laser is used to produce a picosecond 800 nm beam and pump an optical parametric amplifier for generating a femtosecond IR beam. The picosecond 800 nm and IR beams are aligned in a collinear optical path and focused into a quartz crystal with thickness of 50 μm to generate a reference SFG. The picosecond 800 nm, IR and reference SFG beams are refocused on the sample with an angle of 60°. The average power of the 800 nm beam and IR beam are ~10 mW and ~5 mW within ~300 μm spot size. The reference SFG and the SFG signal from the sample go through a ~2 ps time-delay. The interferogram fringe is recorded by a cooled chargecouple device (CCD) camera in 30 seconds. The polarization combination used in this study is PSP for SFG, picosecond 800 nm and IR beams respectively, which can acquire the surface chirality of the sample

29.

The chiral signal can be processed from

the raw interferogram by Fast Fourier Transformation.


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SFG Sample Preparation: Single NP samples: NPs pH= 11.3 solutions (About 1 ml) are added on the silicon substrate repeatedly. NPS samples: The NPS the precipitate products are drop-wise added on the silicon substrate directly. SFG Theory Mechanism: Generally, chiral SFG experiments are carried on using particular polarization combination of incident IR, VIS laser beams and generated SF beam, such as PSP (P-polarized SFG, S-polarized visible, and P-polarized IR), SSP and PPS. In this paper, we adopt PSP as the polarization setting for chirality probing. The intensity of the SF signal is related to the surface effective second order susceptibility,

and the intensities of the incident IR and VIS laser beams: (2)

I SFG   eff

2

I IR IVIS

(1)

with

 = e$SFG  LSFG    S :  LIR  e$IR   LVIS  e$VIS  (2)

(2)

eff

Where

and

the frequency

(2)

are the unit polarization vector and the transmission Fresnel factor at (i= SFG, IR, VIS), respectively;

is the surface macroscopic

second-order susceptibility tensor which contains six chiral orthogonal


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elements, where I, J, K are laboratory coordinates (x, y, z). With the PSP setting ，the can be expressed as

which related to the microscopic hyperpolarizability

of the molecules at surface, 1 2

(2) (2) NS   (2) psp   zyx    zxy  

 cos 2  (  cab   cba )     sin 2  sin 2  ( bca  bac )     sin 2  cos 2  (  abc   acb )     sin 2 sin cos   aac   aca  bbc  bcb      sin cos sin  bab  bba   cac   cca      sin cos cos (  aab   aba   cbc   ccb ) 

(3)

where Ns is the number density of the interface moiety under study;

is the

element of the microscopic hyper polarizability, where i, j, k are molecular coordinates (a, b, c);

and

are the clockwise rotation angles rotating from molecular b axis and c

axis to laboratory coordinates under the z-y-z transformation; The angular brackets denote the orientational averaging. Hence, the experimentally observable ISFG is as a function of βijk and the molecular orientation (

) at surface. From the Eq. (3), it

reveals that the chiral SFG signals are contributed not only by the intrinsic chiral β, i, j, k


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(i≠ j≠ k) elements, but also achiralβ, i, j, k elements, which means the achiral molecules arranged in macromolecular chiral architectures can also provide chiral SFG signal .3033In

case of the intrinsic chirality small, the Eq.3 can be simplified: 1 2

(2) (2) NS   (2) psp   zyx    zxy  

 sin 2 sin cos   aac   aca   bbc   bcb        sin cos sin   bab   bba   cac   cca      sin cos cos (  aab   aba   cbc   ccb )   

(4)

These contributions arising from the achiral components of the molecular tensor are defined as collective chirality. ASSOCIATED CONTENT Supporting Information. The Supporting Information is available free of charge on the ACS Publications website at DOI: XXXXXXXXXXX. Additional experimental data (Figures S1−S5) Additional experimental details and data (PDF)

AUTHOR INFORMATION

Corresponding Authors *E-mail: [email protected] (X. M.);


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*[email protected] (Q. L);

*[email protected] (Y. Sh.);

* [email protected] (J. W) ;

ORCID

Yongtao Shen: 0000-0002-4463-6436

Qifeng Li: 0000-0001-8813-5054

Jiefu Wang: 0000-0001-6164-342X

ACKNOWLEDGMENT This work was financed by Grant-in-aid for scientific research from the National Natural Science Foundation of China (No. 51473116, 21273159) for the Youth of China (No. 81501617, 11604034). .

REFERENCES (1) Pendry, J. B. A Chiral Route to Negative Refraction. Science 2004, 306, 1353-1355.


35

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Page 36 of 45

(2) Lieberman, I.; Shemer, G.; Fried, T.; Kosower, E. M., Markovich, G. PlasmonResonance-Enhanced Absorption and Circular Dichroism, Angew. Chem. Int. Ed. 2008,

47, 4855-4857.

(3) Li, Y.; Zhou, Y.; Wang, H. Y.; Perrett, S.; Zhao, Y.; Tang, Z.; Nie, G. Chirality of Glutathione Surface Coating Affects the Cytotoxicity of Quantum Dots. Angew. Chem.

Int. Ed. 2011, 50, 5860-5864.

(4) Slocik, J. M.; Govorov, A. O.; Naik, R. R. Plasmonic Circular Dichroism of PeptideFunctionalized Gold Nanoparticles. Nano Lett. 2011, 11, 701-705.

(5) Mac Quarrie, S.; Thompson, M. P.; Blanc, A.; Mosey, N. J.; Lemieux, R. P.; Crudden, C. M. Chiral Periodic Mesoporous Organosilicates Based on Axially Chiral Monomers: Transmission of Chirality in the Solid State. J. Am. Chem. Soc. 2008, 130, 14099-14101.

(6) Valev, V. K.; Baumberg, J. J.; Sibilia, C.; Verbiest, T. Chirality and Chiroptical Effects in Plasmonic Nanostructures: Fundamentals, Recent Progress and Outlook. Adv. Mater. 2013, 25, 2517-2534.


36

Page 37 of 45 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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(7) Ben-Moshe, A.; Maoz, B. M.; Govorov, A. O.; Markovich, G. Chirality and Chiroptical Effects in Inorganic Nanocrystal Systems with Plasmon and Exciton Resonances. Chem.

Soc. Rev. 2013, 42, 7028-7041.

(8) Govorov, A. O.; Gunko, Y. K.; Slocik, J. M.; Gérard, V. A.; Fan, Z.; Naik, R. R. Chiral Nanoparticle Assemblies: Circular Dichroism, Plasmonic Interactions and Exciton effects. J. Mater. Chem. 2011, 21, 16806-16818.

(9) Schaaff, T. G.; Whetten, R. L. Giant Gold−Glutathione Cluster Compounds: Intense Optical Activity in Metal-Based Transitions. J. Phys. Chem. B 2000, 104, 2630-2641.

(10) Murray, C. B.; Kagan, C. R.; Bawendi, M. G. Self-Organization of CdSe Nanocrystallites into Three-Dimensional Quantum Dot Superlattices. Science 1995, 270, 1335-1338.

(11) Shevchenko, E. V.; Talapin, D. V.; Kotov, N. A.; O'brien, S.; Murray, C. B. Structural Diversity in Binary Nanoparticle Superlattices. Nature 2006, 439, 55-59.


37

ACS Nano 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 38 of 45

(12) Murray, C. B.; Kagan, C. R.; Bawendi, M. G. Synthesis and Characterization of Monodisperse Nanocrystals and Close Packed Nanocrystal Assembles Packed Nanocrystal Assembles. Annu. Rev. Mater. Sci. 2000, 30, 545-610.

(13) Belkin, M. A.; Kulakov, T. A.; Ernst, K. H.; Yan, L.; Shen, Y. R. Sum-Frequency Vibrational Spectroscopy on Chiral Liquids: a Novel Technique to Probe Molecular Chirality. Phys. Rev. Lett. 2000, 85, 4474-4477.

(14) Ji, N.; Shen, Y. R. A. Novel Spectroscopic Probe for Molecular Chirality. Chirality 2006, 18, 146-158.

(15) Yan, Elsa C. Y.; Fu, L.; Wang, Z. G.; Liu, W. Biological Macromolecules at Interfaces Probed by Chiral Vibrational Sum Frequency Generation Spectroscopy.

Chem. Rev. 2014, 114, 8471-8498.

(16) Fan, H.; Fei, Z.; Yan, L.; Hao, H. DNA Origami: Scaffolds for Creating Higher Order Structures. Chem. Rev. 2017, 117, 12584-12594.


38

Page 39 of 45 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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(17) Simpson, G. J. Molecular Origins of the Remarkable Chiral Sensitivity of SecondOrder Nonlinear Optics. Chem. Phys. Chem. 2004, 5, 1301-1310.

(18) Li, H.C.; Ye, S.J.; Wei, F.; Ma, S.L.; Luo, Y. In situ Molecular-Level Insights into the Interfacial Structure Changes of Membrane-Associated Prion Protein Fragment [118−135] Investigated by Sum Frequency Generation Vibrational Spectroscopy.

Langmuir 2012, 28, 16979-16988.

(19) Ye, S. J.; Wei, F.; Li, H. C.; Tian, K. Z.; Luo,Y. Structure and Orientation of Interfacial Proteins Determined by Sum Frequency Generation Vibrational Spectroscopy: Method and Application. Adv. Protein. Chem. Struct. Biol. 2013, 93, 213-255.

(20) Walter, S. R.; Geiger, F. M. DNA on Stage: Showcasing Oligonucleotides at Surfaces and Interfaces with Second Harmonic and Vibrational Sum Frequency Generation. J. Phys. Chem. Lett. 2009, 1, 9-15.


39

ACS Nano 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 40 of 45

(21) 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.

(22) Haupert, L. M.; Simpson, G.J. Chirality in Nonlinear Optics. Annu. Rev. Phys.

Chem. 2009, 60,345-365.

(23) Simpson, G.J.; Perry, J.M.; Ashmore-Good, C. L. Molecular and Surface Hyperpolarizability of Oriented Chromophores of Low Symmetry. Phys. Rev. B. 2002,

66,165437.

(24) Srivastava, S., Santos, A., Critchley, K., Kim, K. S., Podsiadlo, P., Sun, K.; Kotov, N. A. Light-Controlled Self-Assembly of Semiconductor Nanoparticles into Twisted Ribbons. Science 2010, 327, 1355-1359.

(25) Chen, Y. J.; Yan, X. P. Chemical Redox Modulation of the Surface Chemistry of CdTe Quantum Dots for Probing Ascorbic Acid in Biological Fluids. Small 2009, 5, 2012-2018.


40

Page 41 of 45 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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(26) Sharma, R. C.; Chctng, Y. A. Thermodynamic Optimization of the Ti-C System. J.

Phase Equilib. 1996, 17, 425-431.

(27) Ben-Moshe, A.; Maoz, B. M.; Govorov, A. O.; Markovich, G. Chirality and Chiroptical Effects in Inorganic Nanocrystal Systems with Plasmon and Exciton Resonances. Chem. Soc. Rev. 2013, 42, 7028-7041.

(28) Zhou, Y.; Yang, M.; Sun, K.; Tang, Z.; Kotov, N. A. Similar Topological Origin of Chiral Centers in Organic and Nanoscale Inorganic Structures: Effect of Stabilizer Chirality on Optical Isomerism and Growth of CdTe Nanocrystals. J. Am. Chem. Soc. 2010, 132, 6006-6013.

(29) Jalilehvand, F. Sulfur: not a “Silent” Element any more. Chem. Soc. Rev. 2006, 35, 1256-1268.

(30) Govorov, A. O.; Gun'ko, Y. K.; Slocik, J. M.; Gérard, V. A.; Fan, Z.; Naik, R. R. Chiral Nanoparticle Assemblies: Circular Dichroism, Plasmonic Interactions, and Exciton Effects. J. Mater. Chem. 2011, 21, 16806-16818.


41

ACS Nano 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 42 of 45

(31) Kumar, J.; Thomas, K. G.; Liz-Marzán, L. M. Nanoscale Chirality in Metal and Semiconductor Nanoparticles. Chem. Commun. 2016, 52, 12555-12569.

(32) Li, M.; Zhou, H.; Zhang, H.; Sun, P.; Yi, K.; Wang, M.; Xu, S. J. Preparation and Purification of L-Cysteine Capped CdTe Quantum Dots and its Self-Recovery of Degenerate Fluorescence. Lumin. 2010, 130, 1935-1940.

(33) Nakashima, T.; Kobayashi, Y.; Kawai, T. Optical Activity and Chiral Memory of Thiol-Capped CdTe Nanocrystals. J. Am. Chem. Soc. 2009, 131, 10342-10343.

(34) Wolf, S. E.; Loges, N.; Mathiasch, B.; Panthöfer, M.; Mey, I.; Janshoff, A. ; Tremel, W. Phase Selection of Calcium Carbonate through the Chirality of Adsorbed Amino Acids. Angew. Chem. Int. Ed. 2007, 46, 5618-5623.

(35) Duan, Y.; Han, L.; Zhang, J.; Asahina, S.; Huang, Z.; Shi, L.; Wang, C. The Renaissance of Non-Aqueous Uranium Chemistry. Angew. Chem. Int. Ed. 2015, 54, 15170-15175.


42

Page 43 of 45 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Nano

(36) Liu, Y.; Chen, C.; Wang, T.; Liu, M. Supramolecular Chirality of the TwoComponent Supramolecular Copolymer Gels: Who Determines the Handedness.

Langmuir, 2015, 32, 322-328.

(37) Zhang, L.; Wang, T.; Shen, Z.; Liu, M. Chiral Nanoarchitectonics: towards the Design, Self-Assembly, and Function of Nanoscale Chiral Twists and Helices. Adv.

Mater. 2016, 28, 1044-1059.

(38) Al-Johani, H.; Abou-Hamad, E.; Jedidi, A.; Widdifield, C. M.; Viger-Gravel, J.; Sangaru, S. S.; Gajan, D.; Anjum, D. H.; Ould-Chikh, S.; Hedhili, M. N.; Gurinov, A.; Kelly, M. J.; El Eter, M.; Cavallo, L.; Emsley, L.; Basset, J. M. The Structure and Binding Mode of Citrate in the Stabilization of Gold Nanoparticles. Nat. Chem. 2017, 9, 890-895.

(39) Jalilehvand, F.; Mah, V.; Leung, B. O.; Mink, J.; Bernard, G. M.; Hajba, L. Cadmium(II) Cysteine Complexes in the Solid State: A Multispectroscopic Study. Inorg

Chem. 2009, 48, 4219-4230.


43

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Page 44 of 45

(40) Wang, F.; Wang, D.; Zhou, Y.; Liang, L.; Lu, R.; Chen, P.; Lin, Z.; Liu, G. Divergent Synthesis of CF3-Substituted Allenyl Nitriles by Ligand-Controlled Radical 1,2- and 1,4Addition to 1,3-Enynes. Angew. Chem. Int. Ed. 2018, 57, 7140-7145.

(41) Zhou, Y.; Damasceno, P. F.; Somashekar, B. S.; Engel, M.; Tian, F.; Zhu, J.; Huang, R.; Johnson, K.; McIntyre, C.; Sun, K.; Yang, M.; Green, P. F.; Ramamoorthy, A.; Glotzer, S. C.; Kotov, N. A. Unusual Multiscale Mechanics of Biomimetic Nanoparticle Hydrogels. Nat. Comm. 2018, 9, 181-188.

(42) Belkin, M., Kulakov, T., Ernst, K., Yan, L.; Shen, Y. Sum-Frequency Vibrational Spectroscopy on Chiral Liquids: a Novel Technique to Probe Molecular Chirality. Phys.

Rev. Lett. 2000, 85, 4474-4477.

(43) 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. USA, 2005, 102, 4978-4983.


44

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(44) Okuno, M.; Ishibashi, T. A. Heterodyne-Detected Achiral and Chiral Vibrational Sum Frequency Generation of Proteins at Air/Water Interface. J. Phys. Chem. C, 2015,

119, 9947-9954.

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Self-Assembled Chiral Nanoparticle Superstructures and Identification

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