1
|
Salwadi NFL, Ooi CC, Yeap GY, Suah FBM, Cherin S, Ito MM, Kikuchi K, Fukaya R, Kaneko K, Shimizu A. Synthesis and Molecular Structure of V-Shaped Liquid Crystalline Compounds: Spectroscopic, Mesomorphic, DFT Investigations, Electrochemical and Fluorescence Studies. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2023.135304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
|
2
|
Le KV, Takezoe H, Araoka F. Chiral Superstructure Mesophases of Achiral Bent-Shaped Molecules - Hierarchical Chirality Amplification and Physical Properties. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1602737. [PMID: 27966798 DOI: 10.1002/adma.201602737] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 08/30/2016] [Indexed: 05/27/2023]
Abstract
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.
Collapse
Affiliation(s)
- Khoa V Le
- Department of Chemistry, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan
- RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Hideo Takezoe
- Toyota Physical and Chemical Research Institute, 41-1 Yokomichi, Nagakute, Aichi, 480-1192, Japan
| | - Fumito Araoka
- RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| |
Collapse
|
3
|
Horčic M, Svoboda J, Novotná V, Pociecha D, Gorecka E. Core-to-core dimers forming switchable mesophase. Chem Commun (Camb) 2017; 53:2721-2724. [PMID: 28197564 DOI: 10.1039/c6cc09983a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report structurally new type of dimers composed of bent-core molecules connected through their central cores by an alkylene spacer. Various self-assembling structures are discovered when prolonging the terminal alkyl chains in arms. Among diverse mesophases, the antiferroelectric type of switching under an applied electric field is observed.
Collapse
Affiliation(s)
- M Horčic
- Department of Organic Chemistry, University of Chemistry and Technology, CZ-166 28 Prague 6, Czech Republic.
| | - J Svoboda
- Department of Organic Chemistry, University of Chemistry and Technology, CZ-166 28 Prague 6, Czech Republic.
| | - V Novotná
- Institute of Physics, Academy of Science of the Czech Republic, Na Slovance 2, CZ-182 21 Prague 9, Czech Republic.
| | - D Pociecha
- Laboratory of Dielectrics and Magnetics, Chemistry Department, Warsaw University, Al. Zwirki i Wigury 101, 02-089 Warsaw, Poland.
| | - E Gorecka
- Laboratory of Dielectrics and Magnetics, Chemistry Department, Warsaw University, Al. Zwirki i Wigury 101, 02-089 Warsaw, Poland.
| |
Collapse
|
4
|
Choi SW, Takezoe H. Chirality Enhancement in a Cholesteric Liquid-Crystalline Polymer Doped with Non-Chiral W-shaped Molecules. B KOREAN CHEM SOC 2016. [DOI: 10.1002/bkcs.10932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Suk-Won Choi
- Department of Advance Materials Engineering for Information and Electronics; Kyung Hee University; Yongin 446-701 Korea
- Department of Organic and Polymeric Materials; Tokyo Institute of Technology; Tokyo 152-8552 Japan
| | - Hideo Takezoe
- Department of Organic and Polymeric Materials; Tokyo Institute of Technology; Tokyo 152-8552 Japan
- Toyota Physical and Chemical Research Institute; Aichi 480-1192 Japan
| |
Collapse
|
5
|
Choi SW, Takezoe H. Enhancing and reducing chirality by opposite circularly-polarized light irradiation on crystalline chiral domains consisting of nonchiral photoresponsive W-shaped liquid crystal molecules. SOFT MATTER 2016; 12:7937-7942. [PMID: 27714293 DOI: 10.1039/c6sm01343k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
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.
Collapse
Affiliation(s)
- Suk-Won Choi
- Department of Advance Materials Engineering for Information and Electronics, Kyung Hee University, Yongin-shi, Gyeonggi-do 446-701, Korea. and Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo, 152-8552, Japan
| | - Hideo Takezoe
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo, 152-8552, Japan and Toyota Physical and Chemical Research Institute, 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan.
| |
Collapse
|
6
|
Alaasar M, Prehm M, Tschierske C. Helical Nano-crystallite (HNC) Phases: Chirality Synchronization of Achiral Bent-Core Mesogens in a New Type of Dark Conglomerates. Chemistry 2016; 22:6583-97. [DOI: 10.1002/chem.201505016] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Indexed: 12/20/2022]
Affiliation(s)
- Mohamed Alaasar
- Institute of Chemistry; Martin Luther University Halle-Wittenberg; Kurt Mothes Str. 2 06120 Halle (Saale) Germany), Fax
- Department of Chemistry; Faculty of Science; Cairo University; Giza Egypt
| | - Marko Prehm
- Institute of Chemistry; Martin Luther University Halle-Wittenberg; Kurt Mothes Str. 2 06120 Halle (Saale) Germany), Fax
| | - Carsten Tschierske
- Institute of Chemistry; Martin Luther University Halle-Wittenberg; Kurt Mothes Str. 2 06120 Halle (Saale) Germany), Fax
| |
Collapse
|
7
|
Horčic M, Svoboda J, Seidler A, Kozmík V, Novotná V, Pociecha D, Gorecka E. W-shaped liquid crystalline dimers. RSC Adv 2016. [DOI: 10.1039/c6ra06268g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We present a study of liquid crystalline bent-core dimers with a novel W-shaped molecular structure exhibiting broad polymorphism.
Collapse
Affiliation(s)
- Martin Horčic
- Department of Organic Chemistry
- University of Chemistry and Technology
- CZ-166 28 Prague 6
- Czech Republic
| | - Jiří Svoboda
- Department of Organic Chemistry
- University of Chemistry and Technology
- CZ-166 28 Prague 6
- Czech Republic
| | - Arnošt Seidler
- Department of Organic Chemistry
- University of Chemistry and Technology
- CZ-166 28 Prague 6
- Czech Republic
| | - Václav Kozmík
- Department of Organic Chemistry
- University of Chemistry and Technology
- CZ-166 28 Prague 6
- Czech Republic
| | - Vladimíra Novotná
- Institute of Physics
- Czech Academy of Sciences
- CZ-182 21 Prague 9
- Czech Republic
| | - Damian Pociecha
- Laboratory of Dielectrics and Magnetics
- Chemistry Department
- Warsaw University
- 02-089 Warsaw
- Poland
| | - Ewa Gorecka
- Laboratory of Dielectrics and Magnetics
- Chemistry Department
- Warsaw University
- 02-089 Warsaw
- Poland
| |
Collapse
|
8
|
Kim K, Kim H, Jo SY, Araoka F, Yoon DK, Choi SW. Photomodulated Supramolecular Chirality in Achiral Photoresponsive Rodlike Compounds Nanosegregated from the Helical Nanofilaments of Achiral Bent-Core Molecules. ACS APPLIED MATERIALS & INTERFACES 2015; 7:22686-22691. [PMID: 26397122 DOI: 10.1021/acsami.5b07543] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We prepared a nonchiral mixture of achiral bent-core molecules and photoresponsive rodlike liquid crystalline (LC) molecules. With the help of the isothermal photochemical nematic (N)-isotropic (Iso) phase transition of the photoresponsive rodlike LC molecules, the corresponding phase transition from a dark conglomerate BX phase to another distinguishable dark conglomerate B4 phase took place in the mixture. A large circular dichroism (CD) signal originating from supramolecular chirality was detected in the initial BX phase. On the other hand, the detected CD signal was decreased in the B4 phase after UV irradiation. Interestingly, the decreased CD signal could be reverted to the initial CD signal with visible irradiation. This chiroptical process revealed in this work was stable and reversible and thus opens up the possibility of practical applications such as rewritable optical storage.
Collapse
Affiliation(s)
- Kibeom Kim
- Department of Advance Materials Engineering for Information and Electronics, Kyung Hee University , Yongin-shi, Gyeonggi-do 446-701, Korea
| | - Hanim Kim
- Graduate School of Nanoscience and Technology and KINC, KAIST , Daejeon 305-701, Korea
| | - Seong-Yong Jo
- Department of Advance Materials Engineering for Information and Electronics, Kyung Hee University , Yongin-shi, Gyeonggi-do 446-701, Korea
| | - Fumito Araoka
- Physicochemical Soft Matter Research Unit, RIKEN Center for Emergent Matter Science (CEMS) , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Dong Ki Yoon
- Graduate School of Nanoscience and Technology and KINC, KAIST , Daejeon 305-701, Korea
| | - Suk-Won Choi
- Department of Advance Materials Engineering for Information and Electronics, Kyung Hee University , Yongin-shi, Gyeonggi-do 446-701, Korea
| |
Collapse
|
9
|
Derkach LG, Novikova NS, Górecka E, Kilimenchuk ED. Synthesis of V-Shaped liquid crystal benzoates. RUSS J GEN CHEM+ 2015. [DOI: 10.1134/s1070363215070051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
10
|
Alaasar M, Prehm M, Brautzsch M, Tschierske C. Dark conglomerate phases of azobenzene derived bent-core mesogens - relationships between the molecular structure and mirror symmetry breaking in soft matter. SOFT MATTER 2014; 10:7285-7296. [PMID: 25095778 DOI: 10.1039/c4sm01255k] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
New 4-bromoresorcinol based bent-core molecules with peripheral fluoro substituted azobenzene wings have been synthesized and the liquid crystalline self-assembly was investigated by differential scanning calorimetry (DSC), optical polarizing microscopy (POM), electro-optic studies and X-ray diffraction (XRD). A new type of optically isotropic mesophase composed of chiral domains with opposite handedness (dark conglomerate phases, DC phases) is observed, which for some homologues with medium alkyl chain length is stable down to ambient temperature. It is proposed that these DC phases are formed by helical twisted nano-domains of limited size and composed of the crystallized aromatic cores which are separated by the disordered alkyl chains. This structure is distinct from the previously known soft helical nano-filament phases (HNF phases, B4 phases) formed by extended crystalline nano-filaments and also distinct from the fluid sponge phases composed of deformed fluid layers. Comparison with related bent-core molecules having H, F, Cl, I, CH3 and CN groups in the 4-position at the resorcinol core, either with or without additional peripheral fluorines, provided information about the effects of these substituents on the tendency to form DC phases. Based on these relationships and by comparison with the minimum energy conformations obtained by DFT calculations a hypothesis is provided for the formation of DC phases depending on the molecular structure.
Collapse
Affiliation(s)
- Mohamed Alaasar
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Kurt Mothes Str. 2, D-06120 Halle (Saale), Germany.
| | | | | | | |
Collapse
|
11
|
Takezoe H. Spontaneous Achiral Symmetry Breaking in Liquid Crystalline Phases. Top Curr Chem (Cham) 2011; 318:303-30. [DOI: 10.1007/128_2011_242] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
|
12
|
Sathyanarayana P, Varia MC, Prajapati AK, Kundu B, Sastry VSS, Dhara S. Splay-bend elasticity of a nematic liquid crystal with T-shaped molecules. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 82:050701. [PMID: 21230425 DOI: 10.1103/physreve.82.050701] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 09/14/2010] [Indexed: 05/30/2023]
Abstract
We measured the splay (K11) and bend (K33) elastic constants in the nematic phase of a liquid crystal with T-shaped molecules. We find that the ratio, K33/K11 ≃1 in the entire nematic range except very close to the nematic to Sm-A (SN) transition. Both K33 and K11 show pretransitional divergence as the SN transition is approached from higher temperature. The ratio, K33/K11 suggests that the length (L) to effective width (D) ratio (i.e., L/D ) is significantly smaller due to the presence of long and flexible lateral group, compared to that of rigid rodlike molecules. It is argued that apart from the extra contribution to the elasticity the long and flexible lateral group also has a significant contribution to the suppression of the splay fluctuations in the onset of smectic short-range fluctuation. The structure of the Sm-A phase is investigated by using small angle x-ray diffraction, and a possible arrangement of the molecules in the Sm-A layer is proposed.
Collapse
Affiliation(s)
- P Sathyanarayana
- School of Physics, University of Hyderabad, Hyderabad 500046, India
| | | | | | | | | | | |
Collapse
|
13
|
Choi SW, Kawauchi S, Ha NY, Takezoe H. Photoinduced chirality in azobenzene-containing polymer systems. Phys Chem Chem Phys 2007; 9:3671-81. [PMID: 17622402 DOI: 10.1039/b702835k] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
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.
Collapse
Affiliation(s)
- Suk-Won Choi
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, 152-8552, Japan
| | | | | | | |
Collapse
|
14
|
Pérez-García L, Amabilino DB. Spontaneous resolution, whence and whither: from enantiomorphic solids to chiral liquid crystals, monolayers and macro- and supra-molecular polymers and assemblies. Chem Soc Rev 2007; 36:941-67. [PMID: 17534480 DOI: 10.1039/b610714a] [Citation(s) in RCA: 339] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
One of the great challenges in stereochemistry is the explanation of why some molecules resolve spontaneously while others do not. In this critical review the recent advances in the creation of chiral systems from achiral and racemic compounds in three-, two- and one-dimensional systems are discussed. There are some groups of molecules in some systems that do tend to display conglomerates, which may suggest that there are enantiophobic and enantiophilic molecules whose assembly is guided by the structural and thermodynamic properties of the systems in question.
Collapse
Affiliation(s)
- Lluïsa Pérez-García
- Laboratori de Química Orgànica, Facultat de Farmàcia, and Institut de Nanociència i Nanotecnologia, Universitat de Barcelona, 08028, Barcelona, Spain. mlperez@ ub.edu
| | | |
Collapse
|
15
|
Choi SW, Ha NY, Shiromo K, Rao NVS, Paul MK, Toyooka T, Nishimura S, Wu JW, Park B, Takanishi Y, Ishikawa K, Takezoe H. Photoinduced circular anisotropy in a photochromic W-shaped-molecule-doped polymeric liquid crystal film. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 73:021702. [PMID: 16605351 DOI: 10.1103/physreve.73.021702] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Revised: 10/20/2005] [Indexed: 05/08/2023]
Abstract
Photoinduced circular anisotropy has been demonstrated in thin films of a main-chain polymeric liquid crystal (PLC) system doped with photochromic W-shaped molecules containing two azobenzene groups by irradiating with circularly polarized light (CPL). Reversible photoinduced circular dichroism (CD) was observed with sign relevant to the handedness of the CPL. The experimentally observed CD spectra were analyzed using the DeVoe polarizability model associated with the coupled oscillator method. We also propose a mechanism for the photoinduced circular anisotropy in our system; nucleating the W-shaped molecules with preferential twisted conformation by CPL irradiation, and triggering the local formation of a chiral structure in the W-shaped-molecule-doped main-chain PLC medium.
Collapse
Affiliation(s)
- Suk-Won Choi
- Department of Organic & Polymeric Materials, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|