Takeyasu Tasaka

Yamaguchi University

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Shunsuke Takenaka

Yamaguchi University

H. Okamoto

Yamaguchi University

Yuki Morita

Taisei (Japan)

Vladimir F. Petrov

National Research University of Electronic Technology

Kazuo Kasatani

Yamaguchi University

Hidetoshi Kita

Yamaguchi University

Kosuke Kawabe

Yamaguchi University

Hiroaki Okamoto

Kyoto University

Meili Duan

University of California, Davis

Remuto Yamaguchi

Yamaguchi University

Cooperative Institutions

Yamaguchi University

Materials Science & Engineering

Scientific Research Institute of Organic Intermediates and Dyes

National Institute of Advanced Industrial Science and Technology

Kyoto University

Osaka University

Renji Hospital

Russian Academy of Sciences

Lomonosov Moscow State University

Chinese Academy of Sciences

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Gelation of 1-Alkoxy-4-(2-Perfluoroalkyl)Ethoxybenzenes in Organic Solvents

Molecular Crystals and Liquid Crystals (2005)

Yuki Morita Takeyasu Tasaka Kosuke Kawabe H. Okamoto Shunsuke Takenaka

ABSTRACT This paper describes preparation and physico-chemical properties of 1-alkoxy-4-(2-perfluoroalkyl)ethoxybenzenes (FmOOCn). For FmOOCn, 4-F(CF2)mCH2CH2O-phenyl-O-(CH2)nH, three homologues, m = 8 (n = 1, 2) and m = 10 (n = 1) reveal monotropic smectic A and unidentified smectic phases, respectively. Simultaneously, most of the homologous are possible to gelatinize various organic solvents such as octane, cyclohexane, DMF, ethanol, and so on. The gelation ability increases with increasing the carbon number of the perfluoroalkyl chain. The formed gel is transparent, semitransparent or opaque, and the phase transition between the gel phase and the isotropic fluid is thermally reversible. The images of gel observed with scanning electron microscope (SEM) show gathered fibrous aggregates.

Homologous series

Opacity

10.1080/15421400590957107

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Citations (8)

Physicochemical Properties of New Gelators Based on a Chromen-2-one Core

Chemistry Letters (2005)

Fusheng Zhang Yuki Morita Kosuke Kawabe Takeyasu Tasaka H. Okamoto

Abstract Homologous series of 2-oxochromen-6-yl 4-alkoxybenzoates (1-n, n = 2–10) and 4-alkoxybiphenyl-4′-carboxylates (2-n, n = 5–8) can gelate various organic solvents, where the gel–sol transition temperatures are ca. 60 and 90 °C, respectively.

10.1246/cl.2005.1156

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Liquid Crystalline Properties of Some Derivatives with a Long Lateral Alkoxyl Group

Molecular crystals and liquid crystals science technology. Section A, Molecular crystals and liquid crystals/Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals (2001)

Takeyasu Tasaka Jian Wu H. Okamoto Vladimir F. Petrov Shunsuke Takenaka

Abstract This paper describes the liquid the crystalline properties of 4-(4-alkoxy-phenoxycarbonyl)phenyl 4-bromo-3-alkoxy-(2), 4-cyano-3-alkoxybenzoates(3), and 2-methyl-3-alkoxybenzoates(4). 2 and 3 are essentially smectogenic, while 4 are nematogenic. The difference in the mesomorphic properties is discussed in terms of their molecular geometrical characteristics estimated by a semi-empirical molecular orbital calculation. Key Words: liquid crystalssubstituent effectSmectic Cthermal propertyconformational analysis

10.1080/10587250108025041

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X-ray diffraction study of some liquid crystalline 2,5-disubstituted 1, 3, 2-dioxaborinane derivatives

Vladimir F. Petrov Takeyasu Tasaka H. Okamoto Shunsuke Takenaka V. S. Bezborodov

Abstract X-ray diffraction study of some liquid crystalline 2.5-disubstituted 1,3,2-dioxaborinane derivatives reveals the existence of a partially bilayered smeetic Ad phase in the terminally CF3 and OCF3 substituted derivatives, with the higher level of molecular overlapping in the formation of the dimer observed for the latter compound; and the dimeric density wave fluctuations in the nematic phase of CN substituted derivative.

Derivative (finance)

Liquid phase

10.1080/10587250008031041

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Citations (3)

48.3: Invited Paper: Flexible Liquid Crystal Films for Automotive Switchable Window

SID Symposium Digest of Technical Papers (2021)

Fenghua Li Cai Guo Lin Li Abelma Liang Takeyasu Tasaka

10.1002/sdtp.14478

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Liquid crystalline properties of dissymmetric molecules part X: The effect of a terminal nitro group on molecular arrangement in smectic phases in three aromatic ring systems with two ester groups

Liquid Crystals (2003)

Takeyasu Tasaka H. Okamoto Yuki Morita Kazuo Kasatani Shunsuke Takenaka

Abstract The smectic A (SmA) layer structure has been examined by X-ray diffraction for four isomeric systems: 4-nitrophenyl 4-(4-alkoxybenzoyloxy)benzoates 1, 4-alkoxyphenyl 4-(4-nitrobenzoyloxy)benzoates 2, 4-(4-alkoxybenzoyloxy)phenyl 4-nitrobenzoates 3, and 4-alkoxyphenyl 4-nitrophenyl terephthalates 4. The phase transition behaviour and layer structure of the SmA phases are notably influenced by the relative orientation of the two ester groups to the terminal groups, by alkoxy chain length, and by temperature. The SmA phase for compounds 1 and 3 has a mainly 'monolayer' arrangement, where the layer spacing is 2-5 Å longer than the molecular length. The SmA phase for compounds 2 and 4 consists of a mixed layer structure having monolayer, bilayer, and partially bilayer arrangements, the distribution depending on the relative orientation of the ester groups, the alkoxy chain length, and temperature. It is supposed that the diversity of the SmA phase is related to the polar interaction around the nitro or the nitrobenzene moieties through the smectic layers and reversal of the ester groups causes a subtle change in the entire molecular shape.

Benzoates

Nitrobenzene

10.1080/0267829031000139531

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Citations (10)

O-13 X-RAY DIFFRACTION STUDY OF SOME ACHIRAL LIQUID CRYSTALS

Vladimir F. Petrov Takeyasu Tasaka H. Okamoto Yo Shimizu Shunsuke Takenaka

10.11538/ekitou.2000.0__i_13

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Liquid Crystal Properties of 4-Alkoxy-3-nitrobenzoic Acids

Chemistry Letters (2002)

Takeyasu Tasaka H. Okamoto Yuki Morita Kazuo Kasatani Shunsuke Takenaka

Abstract For the homologous series of 4-alkoxy-3-nitrobenzoic acids the nonyloxy and the higher members exhibit a smectic A phase, where the layer spacings are 1.5–1.6 times of the fully extended molecular lengths.

10.1246/cl.2002.536

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Citations (2)

Smectic Phase Exhibited by Dissymmetric Liquid Crystals: Effect of a Terminal Fluoromethyl Group on Mesomorphic Properties

Ferroelectrics (2002)

Takeyasu Tasaka Shunsuke Takenaka Koji Kabu Yuki Morita H. Okamoto

This paper describes smetic properties of some liquid crystal materials incorporating a terminal trifluoromethyl, a trifluoromethoxy, or a difluoromethoxy group. These groups tend to promote the appearance of smectic A phase with a characteristic molecular arrangement, and the layer structure is discussed in terms of the physical properties of the molecules.

10.1080/00150190214422

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Citations (15)

Liquid crystalline properties of dissymmetric molecules IV. The substituent effect on thermal properties of nematic and smectic A phases in three aromatic ring systems with ester linkages

Liquid Crystals (2000)

Meili Duan Takeyasu Tasaka H. Okamoto Vladimir F. Petrov Shunsuke Takenaka

This paper describes the effect of substituent and ester linkage on smectic properties for some derivatives of 4-R -phenyl 4-(4-octyloxybenzoyloxy)benzoates (1), 4-octyloxyphenyl 4-(4-R-benzyloxy)benzoates (2), 4-(4-octyloxybenzoyloxy)phenyl 4- R -benzoates (3), and 4-R-phenyl 4-octyloxyphenyl terephthalates (4) where R = OCH3, CH3, OC8H17, C8H17, halogens, CF3, OCF3, CN, NO2, etc. The thermal properties are discussed in terms of the electrostatic nature of the substituents and the relative orientation of the ester groups with respect to both terminal substituents. The substituent effect on the layer structure of the smectic A phase is also examined by means of a small angle X-ray analysis.

Benzoates

10.1080/02678290050122042

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Citations (24)