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Transfer and Dynamic Inversion of Co-Assembled Supramolecular Chirality through 2D-Sheet to Rolled-Up Tubular Structure Heekyoung Choi, Kang Jin Cho, Hyowon Seo, Junho Ahn, Jinying Liu, Shim Sung Lee, Hyungjun Kim, Chuanliang Feng, and Jong Hwa Jung J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/jacs.7b09760 • Publication Date (Web): 21 Nov 2017 Downloaded from http://pubs.acs.org on November 21, 2017
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Journal of the American Chemical Society
Transfer and Dynamic Inversion of Co-Assembled Supramolecular Chirality through 2D-Sheet to Rolled-Up Tubular Structure Heekyoung Choi,† Kang Jin Cho,‡ Hyowon Seo,† Junho Ahn,† Jinying Liu,§ Shim Sung Lee,† Hyungjun Kim,*,‡ Chuanliang Feng,*,§ and Jong Hwa Jung*,† †
Department of Chemistry and Research Institute of Natural Sciences, Gyeongsang National University, Jinju 52828, Republic of Korea ‡ Graduate School of Energy, Environment, Water and Sustainability, KAIST, Daejeon 34141, Republic of Korea § School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China Supporting Information Placeholder ABSTRACT: Transfer and inversion of supramolecular chirality from chiral calix[4]arene analogs (3D and 3L) with an alanine moiety to an achiral bipyridine derivative (1) with glycine moieties in a co-assembled hydrogel are demonstrated. Molecular chirality of 3D and 3L could transfer supramolecular chirality to an achiral bipyridine derivative 1. Moreover, the addition of 0.6 equiv. of 3D or 3L to 1 induced the supramolecular chirality inversion of 1. More interestingly, the 2D-sheet structure of the coassembled hydrogels formed with 0.2 equiv. of 3D or 3L changed to a rolled-up tubular structure in the presence of 0.6 equiv. of 3D or 3L. The chirality inversion and morphology change are mainly mediated by intermolecular hydrogen-bonding interactions between the achiral and chiral molecules, which might be induced by reorientations of the assembled molecules, as confirmed by density functional theory (DFT) calculations.
Helical motifs (e.g., DNA or proteins) are very common in many biomolecular systems, where they perform helicity inversion in many physiological processes along with specific biofunction transformations.1-3 Inspired by these biological helices and the corresponding helical chirality inversion phenomenon, many chemists have attempted to design smart systems with tunable helical chirality and to use such systems in practical applications.4-11 In this regard, stimuli-responsive supramolecular assemblies provide a new platform in which helical preference can be mediated by external stimuli12 such as a change in solvent13 or temperature,14 light irradiation,15 pH,16 the addition of chemical species,17-19 or rotary stirring.20,21 Because a dynamic helical inversion system could be used to detect the activity of chemical process and elucidate their function in biological systems, several groups have fabricated systems that dynamically respond to such stimuli and enable real-time chiroptical reading of various helical transitions.11,13,18 For instance, George’s group investigated a supramolecular system that can sense the activity of adenosine phosphate, however, this system could only observe the activity on the molecular level using circular dichroism (CD) absorption spectroscopy.22 Oda’s group fabricated another dynamic helical inversion system that can monitor the process of helical transition using CD spectroscopy and allows visualization of the process of molecular chirality transfer and inversion via transmission electron microscopy (TEM).23
Construction of well-defined 1D-nanostructures such as fibers, tubes, and helical coils from aqueous self-assemblies has seen a wealth of applications for materials science.24 The incorporation of a stimuli-responsive moiety into the molecular building block allows the formation of nanofibers exhibiting external stimuliresponsive changes in shape.25 Among the diverse 1Dnanostructures, the hollow tubular structures have a great potential to be applied in various areas.24 An alternative strategy to construct the hollow tubular structure is rolling-up of 2D-sheets in one direction to form tubular scrolls.11,26 However, determination and regulation of the rolling-up direction by enantiomer have been rarely reported.11
Figure 1. Chemical structures of glycine-appended bipyridine derivatives 1, 2 and alanine appended calix[4]arene 3D, 3L. To address this problem, we selected two achiral bipyridine analogs (1 and 2) and calix[4]arene-based (3D and 3L) building blocks as basic units for constructing supramolecular chiral nanostructures. The two achiral bipyridines (1 and 2), each having one or two glycine groups at both ends, were used to regulate the chirality of the nanostructures. We unexpectedly found that the calix[4]arene derivatives (3D and 3L) transfer their chiral sense to the achiral bipyridine derivative 1. As shown in Figure 1 and Scheme S3, achiral compound 1 generated supramolecular chirality upon addition of enantiomer 3D (Figures S9 and S10) or 3L. More interestingly, P-helicity (right-handed) of 1 in co-assembled hydrogel (co-hydrogel) 1D-0.2 formed at a 3D-to-1 mole ratio of 0.2 was inverted into M-helicity (left-handed) when the concentration of 3D was increased beyond 0.5 equiv. In addition, a 2Dsheet structure of co-assembled hydrogels formed with 0.2 equiv. of 3D or 3L was immediately rolled into a tubular structure in the presence of 0.4 equiv. of 3D or 3L. These processes were shown to be mediated mainly by intermolecular hydrogen bonding inter-
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actions between the achiral molecule (1) and the enantiomers (3D and 3L) during co-assembly, which can further induce different rearrangements and assemblies. By contrast, the chirality of 1 in co-hydrogel 1L comprising 1 and 3L was completely opposite that of co-hydrogel 1D (1 + 3D) at the molecular and supramolecular levels. The formation of self-assembled nanostructures was initially investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). The SEM images of co-hydrogel 1D-0.2 (formed with 0.2 equiv. of 3D relative to 1) show 2D-sheet structures with in-plane parallel arrangements of nanofibers (Figure 2A), demonstrating that the preformed nanofibers laterally associate to generate planar sheet structures. More interestingly, a rolled-up tubular structure obtained from co-hydrogel 1D-1.0 at a 3D-to-1 mole ratio of 1.0 clearly exhibited left-handed scroll marks (Figure 2B and 2E). The AFM and TEM images of co-hydrogel 1D-0.2 revealed planar sheets with a thickness of 8 nm, consistent with the expected thickness of a single layer (Figures 2C, S11A, and S12A). In great contrast to co-hydrogel 1D-0.2, which exhibited a robust planar sheet structure, co-hydrogel 1D at a 3D-to-1 mole ratio of 0.4 spontaneously rolled into highly curved scrolls and 2D-sheet structures and rolled-up tubular structures coexisted at this point (Figure S13B;b). Over a 3D-to-1 mole ratio of 0.6, all of the 2Dsheets fully rolled into curved scrolls and only rolled-up tubular structure was shown (Figures 2D, S11B, S12B and S13B;c,d,e). In addition, co-hydrogel 1L-0.2 showed a 2D-sheet structure which was shown in co-hydrogel 1D-0.2 (Figure S13A;a). However, this 2D-sheet structure was also converted into the rolled-up tubular structure with a right-handed scroll mark at high concentrations (>0.4 equiv.) of 3L (Figures 2F and S13A;b,c,d,e).
Figure 2. SEM and AFM images of co-hydrogels 1D (1 + 3D) and 1L (1 + 3L). The images demonstrate the mole-ratioresponsive transformation of co-assembled supramolecular structures: (A) unrolled nanosheets at co-hydrogel 1D (3D-to-1 mole ratio = 0.2) and (B) fully rolled-up tube at 1D (3D-to-1 mole ratio = 1.0). (C and D) AFM topography images corresponding in (A) and (B), respectively. (E) Left-handed tube obtained from cohydrogel 1D-1.0 and (F) right-handed tube obtained from cohydrogel 1L-1.0. Co-hydrogel 2D or 2L prepared with 2, having only one glycine moiety at both ends, and a low concentration (0.2 equiv.) of 3D or 3L showed a 2D-sheet structure (Figure S14A). However, by contrast with co-hydrogels 1D and 1L, the 2D-sheet structure of co-hydrogel 2D or 2L formed in the presence of a low concentration of 3D or 3L was not changed in a high concentration of 3D or 3L (Figure S14B), indicating that the number of glycine groups is important to the chirality inversion in co-hydrogels 1D and 1L. We also observed SEM images of co-hydrogel 1DL prepared with 1 and 1:1 mixture (racemic) of 3D and 3L (Figure S15). Co-
hydrogel 1DL with a low concentration of the racemic mixture showed 2D-sheet structure as expected, and it remained as a main morphology even in co-hydrogel with a high concentration of the racemic mixture (Figure S15A and S15B). However, both rightand left-handed tubular structures were also observed at high concentration of the racemic mixture, suggesting that three different types of self-assemblies coexisted in co-hydrogel 1DL by respective influence of pure 3D or 3L, or both 3D and 3L (Figure S15C, S15D and Scheme S4).
Figure 3. Circular dichroism (CD) spectra of (A) co-hydrogel 1D (1 + 3D) or (B) 1L (1 + 3L) as equivalents of 3D (0.2–1.2 equiv.). (C) Plot of the CD from figure (A) and (B) at 312 nm as a function of the equivalents of 3D or 3L. (D) Morphological transformation of the co-hydrogel with increasing equivalents of 3D or 3L: Sheet of co-hydrogel 1D or 1L rolled to form tubes. We investigated the supramolecular chirality of the cohydrogels by circular dichroism (CD) spectroscopy. Figure 3A shows the CD spectra of co-hydrogel 1D in the presence of various concentrations of 3D. The CD signal of the co-hydrogel 1D formed at a mole ratio less than 0.04 was almost silent in the wavelength range 250–450 nm, which we ascribe to the achiral bipyridine derivative 1 chromophores, even though 3D is a chiral molecule. Interestingly, the positive CD signal at 320 nm of cohydrogel 1D in cases where the 3D-to-1 mole ratio was greater than 0.04 was gradually enhanced, reaching maximum at a 3D-to1 mole ratio of 0.2, which corresponds to a bipyridine moiety of 1 (Figure S16). The positive CD signal indicates that the achiral bipyridine moieties of 1 in co-hydrogel 1D are orientated to Phelicity (right-handed).8,18 These results indicate that the molecular chirality of 3D in co-hydrogels was transferred to the achiral bipyridine moiety of 1. When the 3D-to-1 mole ratio was greater than 0.2, the intensity of the CD signal of co-hydrogel 1D again gradually decreased; the CD signal eventually became negative in the case of co-hydrogel 1D-0.6 (prepared with 0.6 equiv. of 3D) (Figure 3A), whose CD signal exhibited ca. 20 nm blue-shift relative to the signal of cohydrogel 1D-0.2. The decrease of the positive CD signal was due to the coexistence of two different molecular aggregates with opposite chirality (see the left side of Scheme S3). SEM and CD observations indicate that the chirality of the 2D-sheet structure in co-hydrogel 1D-0.2 was opposite that of the rolled tubular structure of co-hydrogel 1D-1.0. Furthermore, these results clearly imply that a decrease of CD intensity was due to a change from Phelicity of aggregates to M-helicity (left-handed) in the range from 0.2 to 0.6 equiv. of 3D. The negative CD signal indicates that the achiral bipyridine moiety of 1 was orientated to Mhelicity (left-handed) at 0.6 equiv. of 3D. The helicity conversion from P-helicity to M-helicity in co-hydrogel 1D was mainly af-
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Journal of the American Chemical Society fected by concentration of 3D and this is a unique example that the M-helicity occurs from D-enantiomer (Figure S17). By contrast, the CD spectra of co-hydrogel 1L formed by the addition of a small amount of 1L-0.2 (0.2 equiv.) to 1 exhibit a negative Cotton effect at 320 nm (Figure 3B), which is exactly opposite the behavior of co-hydrogel 1D formed from a mixture of 3D and 1. This negative CD signal indicates that the bipyridine moiety of 1 was orientated in the left-handed (M-type) direction. The negative CD signal of co-hydrogel 1L was inverted into the positive CD sgnal when 0.6 equiv. of 3L was added to 1, which is consistent with the rolling direction of the tubular structure observed by SEM (Figure 2F). This chiral inversion was obviously triggered by chiral 3L, which differs from previous approaches of inducing chiral inversion.12 As a reference experiment, we compared the CD spectra of cohydrogel 2D with one glycine moiety at both end groups of bipyridine derivative 2 with the spectra of 3D. The positive CD signal of co-hydrogel 2D was gradually enhanced when 3D was added to 2, indicating that the molecular chirality of the alanine moiety in calix[4]arene could be transferred to the bipyridine moiety of 2 (Figure S18). However, the CD intensity of co-hydrogel 2D was 25-fold smaller than that of co-hydrogel 1D formed from a mixture of 3D and 1. Furthermore, the positive CD signal did not invert to the negative CD signal when 1.0 equiv. of 3D was added to 2. This tendency of the CD signals is consistent with the SEM image in Figure S14. These findings suggest that the chirality of co-hydrogel 2D was not influenced by the molecular chirality of 3D. The fluorescence spectra of co-hydrogel 1D were also observed (Figure S19). Intensities of two broad bands centered at 381 and 454 nm in the fluorescence spectrum of co-hydrogel 1D-0.2 were ca. 3-fold enhanced as compared with those in the fluorescence spectrum of 1 solution, indicating that the mobility of 1 decreased with transformation of 1 solution into gel state. In contrast, the fluorescence intensity of co-hydrogel 1D-1.0 diminished with quenching effect by the electrostatic interaction between 1 and 3D.27 The co-assembly mechanism of hydrogels was investigated by Fourier transform infrared (FTIR) spectroscopy, which can provide valuable information about the interaction of supramolecular aggregates at the molecular level. Compound 1 in deuterated dimethyl sulfoxide (DMSO-d6) was first characterized by FTIR; the resultant spectrum shows well-defined amide I bands centered at 1657 cm−1, amide II bands centered at 1538 cm−1 (Figure S20). By contrast, the FTIR spectrum of the as-prepared 1D-0.2 xerogel clearly shows well-defined amide I and II bands centered at 1635 and 1544 cm−1, respectively (Figure S21A). The amide I band is separated into two bands, enabling the amide I originating from 1 to be clearly distinguished from that originating from 3D via a curve-fitting method. In the spectrum of co-hydrogel 1D-1.0, the amide I band of 1 is slightly shifted to longer wavenumbers, indicating that the hydrogen bonds (H-bonds) between glycine and glycine moieties are relatively weaker than those in co-hydrogel 1D-0.2 (Figure S21B). Interestingly, new bands at 2540 and 2000 cm−1 appeared as the concentration of 3D was increased; these bands originate from –OH stretching vibrations.28 The intensities of these vibration bands also increased gradually with increasing concentration of 3D (Figure S22), which we attributed to an increase of the binding strength of the H-bonds between the nitrogen atoms of bipyridine moiety of 1 and the –COOH group of 3D. These results clearly suggest the formation of carboxylic acid– pyridine H-bonds in co-hydrogel 1D. In particular, the strong Hbonding interaction between the carboxylic acid of 3D and the bipyridine of 1 would lead to the inversion of supramolecular chirality in this co-assembled hydrogel.
In the case of co-hydrogel 2D, the FTIR spectrum of xerogel 2D-0.2 displays amide I and II bands centered at 1694 and 1548 cm−1, respectively (Figure S23A). No significant changes are observed for the amide I and II bands in the spectrum of cohydrogel 2D-1.0 compared with those in the spectrum of cohydrogel 2D-0.2, indicating that the supramolecular nanostructure of 2D-0.2 is the same as that in the case of 1.0 equiv. of 3D (Figure S23B). Furthermore, the vibration bands at 2500 and 1960 cm−1 in the spectrum of xerogel 2D were almost unchanged after the mole ratio of 3D was increased (Figure S24), indicating weak interactions between the nitrogen atoms of 2 and the –COOH group of 3D. The optical activity and chirality of these co-hydrogels were investigated by vibrational circular dichroism (VCD) spectroscopy (Figure S25). The co-hydrogel 1D-0.2 exhibited a (+/−) VCD signal of the band at 1700–1550 cm−1, whereas the VCD signal of this band switched to a significant (−/+) pattern in the spectrum of co-hydrogel 1D-1.0. Thus, on the basis of the vibrational amide I stretching band at ~1635 cm−1, a strong and extensive C=O┅H-N H-bonding network was inferred to significantly stabilize the coassembled supramolecular co-hydrogels. The VCD patterns imply the inversion and transfer of the chirality from 3D to 1 at room temperature. Because co-hydrogel 1D has the same R-type stereocenter within the d-alanine units, differential VCD behavior between cohydrogels formed at different concentrations (0.2 and 1.0 equiv.) of 3D could result in the formation of distinct aggregates with opposite handedness using the same chiral molecule. In this very rare two-component supramolecular hydrogel system, handedness was successfully controlled by the co-assembly of 1 with different concentrations of 3D. The results strongly suggest that the dynamic supramolecular chirality of nanostructures is not only determined by the chirality of the monomer (3D) but also strongly influenced by the aggregation mode of building blocks through strong and extensive intermolecular H-bonding between –COOH and the N of pyridine.
Figure 4. Proposed structural of co-assembled supramolecular helical structure of co-hydrogel 1D-1.0 (1+3D) (left side) and 1L1.0 (1+3L) (right side); (a) hydrogen bonds formed between the carboxylic acid in 1 and pyridine in 3D molecules and (b) between bipyridine moieties of 1. To understand the differential VCD behavior, we performed density functional theory (DFT) calculations to optimize the achiral bipyridine derivative 1 and then VCD spectra of the optimized structures were calculated (See Supporting Information). DFT optimized molecular structure of 1 shows a helical structure, which is manifested by the intramolecular hydrogen bonds as shown in Figure S26A and S26B. We found that 1 forms
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four intramolecular hydrogen bonds due to the carbonyl and amine groups with distances of ~2.09 Å and ~3.80 Å. Two hydrogen bonds are formed by N51, N14 in hydrazide group and H65, H28 in glycine group with distance of 2.09 Å. H73, H36 in hydroxyl group and O55, O18 in glycine group also form two hydrogen bonds with distance 3.80 Å. These hydrogen bonds could determine right- or left- handed orientation of 1, and the orientation would be affected by enantiomers. Depending on the handedness, the calculated VCD spectra show very distinct behavior particularly at 1660-1560 cm-1 (Figure S26C), in agreement with the experiments. This suggests that the (+/-) pattern of the experimental VCD signal of 1D-0.2 at 1660-1560 cm-1 can be assigned to the formation of right-handed structure of 1, while the (-/+) pattern of the experimental VCD signal of 1D1.0 can be assigned to the formation of left-handed structure of 1 in the gel. Interestingly, this VCD peak assignment suggests that the assembly of microscopic right(left)-handed structures of 1 leads to the macrosopic P(M)-helicity in the gel. Since the lack of chiral center of 1 leads to the same energies both for the right-handed and left-handed structures as alone, one can infer that the intermolecular interaction between 1 and 3D stabilizes one specific-type of handedness, which is dependent on the relative ratio of 1 and 3D. In combined with the FT IR data, we conceive that the intermolecular hydrogen bonds, which is likely to be in the form of carboxylic acid-pyridine hydrogen bonds, are the atomistic origin of the specific handedness. On the basis of these combined experimental and DFT data, we schematically propose a structural unit of co-hydrogel 1D-1.0 and 1L-1.0 in Figure 4 and S27, which is constructed by symmetrically placing two molecules of 1 around 3D or 3L in order that the carboxylic acid-pyridine hydrogen bonds are formed between the molecules. In conclusion, dynamic supramolecular chirality based on achiral building blocks enabled molecular chirality transfer via intermolecular H-bonds between achiral and chiral molecules. It also enabled controlled, reversible conversion between P- and M-type helices via the concentration of chiral, which induce stereoselective interactions and different reorientations. The supramolecular chirality inversion also induced remarkable changes in morphology, where a 2D-sheet structure was rolled into tubular structures. The number of glycine moieties of the achiral building block plays an essential role in chirality inversion. This system is a very rare example of an achiral molecule triggering chirality inversions of nanostructures through co-assembly with a chiral component. This method can be used in complementary studies involving control of the chirality of nanostructures and for exploring their role in environments where chiral and achiral molecules are in close proximity, such as in biological or self-assembled aggregates.
ASSOCIATED CONTENT Supporting Information Experimental details, Scheme S1-4, Supplementary Figures S127. This material is available free of charge via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION Corresponding Author *
[email protected];
[email protected];
[email protected] ACKNOWLEDGMENT This work was supported by the NRF (2015R1A2A2A05001400 and 2017R1A4A1014595) from the Ministry of Sience, ICT and
Future Planning, Korea. In addition, the Innovation Program of Shanghai Municipal Education Commission (201701070002E00061).
REFERENCES (1) Belmont, P.; Constant, J. F.; Demeunynck, M. Chem. Soc. Rev. 2001, 30, 70-81. (2) Rich, A.; Zhang, S. Nat. Rev. Genet. 2003, 4, 566-572. (3) Whitford, D. Proteins, Structure and Function; Wiley: Chichester, 2005. (4) Yashima, E.; Ousaka, N.; Taura, D.; Shimomura, K.; Ikai, T.; Maeda, K. Chem. Rev. 2016, 116, 13752-13990. (5) Liu, M.; Zhang, L.; Wang, T. Chem. Rev. 2015, 115, 73047397. (6) Miyake, H.; Tsukube, H. Chem. Soc. Rev. 2012, 41, 69776991. (7) Aparicio, F.; Nieto-Ortega, B.; Najera, F.; Ramirez, F. J.; Lopez Navarrete, J. T.; Casado, J.; Sanchez, L. Angew. Chem. Int. Ed. 2014, 53, 1373-1377. (8) Liu, G. F.; Zhu, L. Y.; Ji, W.; Feng, C. L.; Wei, Z. X. Angew. Chem. Int. Ed. 2016, 55, 2411-2415. (9) Rodriguez, R.; Quinoa, E.; Riguera, R.; Freire, F. J. Am. Chem. Soc. 2016, 138, 9620-9628. (10) Kang, J.; Miyajima, D.; Itoh, Y.; Mori, T.; Tanaka, H.; Yamauchi, M.; Inoue, Y.; Harada, S.; Aida, T. J. Am. Chem. Soc. 2014, 136, 10640-10644. (11) Wang, Y.; Kim, Y.; Lee, M. Angew. Chem. Int. Ed. 2016, 55, 13122-13126. (12) Lv, Z.; Chen, Z.; Shao, K.; Qing, G.; Sun, T. Polymers 2016, 8, 310. (13) Gillissen, M. A.; Koenigs, M. M.; Spiering, J. J.; Vekemans, J. A.; Palmans, A. R.; Voets, I. K.; Meijer, E. W. J. Am. Chem. Soc. 2014, 136, 336-343. (14) Maeda, K.; Mochizuki, H.; Watanabe, M.; Yashima, E. J. Am. Chem. Soc. 2006, 128, 7639-7650. (15) Zhao, D.; van Leeuwen, T.; Cheng, J.; Feringa, B. L. Nat. Chem. 2017, 9, 250-256. (16) Huang, Z.; Kang, S.-K.; Banno, M.; Yamaguchi, T.; Lee, D.; Seok, C.; Yashima, E.; Lee, M. Science 2012, 337, 15211526. (17) Akine, S.; Sairenji, S.; Taniguchi, T.; Nabeshima, T. J. Am. Chem. Soc. 2013, 135, 12948-12951. (18) Deng, M.; Zhang, L.; Jiang, Y.; Liu, M. Angew. Chem. Int. Ed. 2016, 55, 15062-15066. (19) Zimbron, J. M.; Caumes, X.; Li, Y.; Thomas, C. M.; Raynal, M.; Bouteiller, L. Angew. Chem. Int. Ed. 2017, 56, 14016-14019. (20) Amabilino, D. B. Nat. Mater. 2007, 6, 924-925. (21) Buendía, J.; Calbo, J.; Ortí, E.; Sánchez, L. Small 2017, 13, 1603880. (22) Kumar, M.; Brocorens, P.; Tonnele, C.; Beljonne, D.; Surin, M.; George, S. J. Nat. Commun. 2014, 5, 5793. (23) Tamoto, R.; Daugey, N.; Buffeteau, T.; Kauffmann, B.; Takafuji, M.; Ihara, H.; Oda, R. Chem. Commun. 2015, 51, 35183521. (24) Kim, H.-J.; Kim, T.; Lee, M. Acc. Chem. Res. 2011, 44, 7282. (25) Muraoka, T.; Cui, H.; Stupp, S. I. J. Am. Chem. Soc. 2008, 130, 2946-2947. (26) Hong, D.-J.; Lee, E.; Jeong, H.; Lee, J.-k.; Zin, W.-C.; Nguyen, T. D.; Glotzer, S. C.; Lee, M. Angew. Chem. Int. Ed. 2009, 48, 1664-1668. (27) Prashanthi, S.; Bangal, P. R. Chem. Commun. 2009, 17571759. (28) Liu, G.; Liu, J.; Feng, C.; Zhao, Y. Chem. Sci. 2017, 8, 1769-1775.
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