Chirality Induced by Circularly Polarized Light in Liquid Crystalline Twin Dimers with Azo Linkages

Hoshino, Yusuke; Choi, Suk–Won; Izumi, Tatsuya; Takanishi, Yoichi; Ishikawa, Ken; Watanabe, Junji; Takezoe, Hideo

doi:10.1080/15421400701205735

Cited by 6 publications

(4 citation statements)

References 30 publications

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“…Recently, we introduced photoinduced chirality in a bentshaped twin dimeric compound (9) which can be regarded as a model compound of main-chain type polymers. 45 The compound used was a,o-bis(4-alkoxyazobenzene-4 0 -carbonyloxy)alkenes, in which two azobenzene moieties with alkoxy tails are linked by a polymethylene spacer, and showed the following phase sequence; isotropic-(108 1C)-SmC A -(94 1C)-B4. The lowest temperature B4 phase 11 is a solid-like phase, but is considerably different from a crystal in several aspects.…”

Section: Dimeric Compound With Azobenzene Linkagementioning

confidence: 99%

“…The lowest temperature B4 phase 11 is a solid-like phase, but is considerably different from a crystal in several aspects. 4,45 The notable feature is that microscopically chiral segregation occurs spontaneously in the B4 phase. The origin for the chirality of the B4 phase is regarded as twisted conformations of molecules, which was attested by nuclear magnetic resonance (NMR) measurement and molecular calculations (Fig.…”

Section: Dimeric Compound With Azobenzene Linkagementioning

confidence: 99%

“…A more concrete explanation was given in our previous papers. 4,45 Because of the absorption difference for R-and L-CPL, one of the twisted conformers becomes preferential under CPL irradiation according to the CPL analogue of the ''Weigert effect''. The details of the mechanism will be described in a more general way in section 3.4.…”

Section: Dimeric Compound With Azobenzene Linkagementioning

confidence: 99%

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Photoinduced chirality in azobenzene-containing polymer systems

Choi

Kawauchi

et al. 2007

Phys. Chem. Chem. Phys.

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In this article, we will review the phenomena on circularly-polarized-light (CPL)-induced chirality in polymeric systems with photochromophores in their side-chain or main-chain. In the side-chain polymeric systems, the photoinduced chirality arises from superstructural chirality, i.e., helix structure, via aggregating of achiral azobenzene molecules in side chains. On the other hand, in the main-chain polymeric system, the macroscopically induced chirality can originate from individual chirality of chromophores in their main-chain backbone. The CPL irradiation on polymeric films with photochromophores to produce macroscopic chirality has been realized as potentially useful in the development of optical-switching, optical-storage, and light-driven devices.

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Section: Dimeric Compound With Azobenzene Linkagementioning

confidence: 99%

Section: Dimeric Compound With Azobenzene Linkagementioning

confidence: 99%

Section: Dimeric Compound With Azobenzene Linkagementioning

confidence: 99%

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Photoinduced chirality in azobenzene-containing polymer systems

Choi

Kawauchi

et al. 2007

Phys. Chem. Chem. Phys.

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“…20 The same as previous examples, the HNF phase microscopically segregates into two chiral domains with equal probabilities. Many attempts have been successfully made for controlling chirality [22][23][24][25][26] and uniformly aligning HNFs. 27,28 In these studies, chirality control and uniform alignment of HNFs are possible, if the controlling processes are conducted during the phase transition to the B 4 (HNF) phase from the upper phases such as normal smectic or nematic phases.…”

Section: Introductionmentioning

confidence: 99%

Enhancing and reducing chirality by opposite circularly-polarized light irradiation on crystalline chiral domains consisting of nonchiral photoresponsive W-shaped liquid crystal molecules

Choi

Takezoe

2016

Soft Matter

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We found possible chirality enhancement and reduction in chiral domains formed by photoresponsive W-shaped molecules by irradiation with circularly polarized light (CPL). The W-shaped molecules exhibit a unique smectic phase with spontaneously segregated chiral domains, although the molecules are nonchiral. The chirality control was generated in the crystalline phase, which shows chiral segregation as in the upper smectic phase, and the result appeared to be as follows: for a certain chiral domain, right-CPL stimuli enhanced the chirality, while left-CPL stimuli reduced the chirality, and vice versa for another chiral domain. Interestingly, no domain-size change could be observed after CPL irradiation, suggesting some changes in the causes of chirality. In this way, the present system can recognize the handedness of the applied chiral stimuli. In other words, the present material can be used as a sensitive chiral-stimuli-recognizing material and should find invaluable applications, including in chiroptical switches, sensors, and memories as well as in chiral recognition.

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Chiral Superstructure Mesophases of Achiral Bent‐Shaped Molecules – Hierarchical Chirality Amplification and Physical Properties

Takezoe

Araoka

2016

Advanced Materials

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Chiral mesophases in achiral bent-shaped molecules have attracted particular attention since their discovery in the middle 1990s, not only because of their homochirality and polarity, but also due to their unique physical/physicochemical properties. Here, the most intriguing results in the studies of such symmetry-broken states, mainly helical-nanofilament (HNF) and dark-conglomerate (DC) phases, are reviewed. Firstly, basic information on the typical appearance and optical activity in these phases is introduced. In the following section, the formation of mesoscopic chiral superstructures in the HNF and DC phases is discussed in terms of hierarchical chirality. Nanoscale phase segregation in mixture systems and gelation ability in the HNF phase are also described. In addition, some other related chiral phases of bent-shaped molecules are shown. Recent attempts to control such mesoscopic chiral structure and the alignment/confinement of HNFs are also discussed, along with several examples of their fascinating advanced physical properties, i.e. huge enhancement of circular dichroism, electro- and photo-tunable optical activities, chirality-induced nonlinear optics (second-harmonic-generation circular difference and electrogyration effect), enhanced hydrophobicity through the dual-scale surface morphological modulation, and photoconductivity in the HNF/fullerene binary system. Future prospects from basic science and application viewpoints are also indicated in the concluding section.

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Chirality Induced by Circularly Polarized Light in Liquid Crystalline Twin Dimers with Azo Linkages

Cited by 6 publications

References 30 publications

Photoinduced chirality in azobenzene-containing polymer systems

Photoinduced chirality in azobenzene-containing polymer systems

Enhancing and reducing chirality by opposite circularly-polarized light irradiation on crystalline chiral domains consisting of nonchiral photoresponsive W-shaped liquid crystal molecules

Chiral Superstructure Mesophases of Achiral Bent‐Shaped Molecules – Hierarchical Chirality Amplification and Physical Properties

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