Kenjiro Uno

Liquid-Crystalline Behavior and Photoluminescence Properties of Gold(I) Complex: Relationship between Aggregation Structure and Properties

Liquid-crystalline (LC) behavior and photoluminescent properties of a gold(I) complex, 2 were investigated. It was confirmed that the complex showed enantiotropic LC phases. In addition, we found that the complex showed strong photoluminescence in the condensed phases, but no luminescence was observed in a dilute solution. The single-crystal X-ray structure analysis suggested that the complex formed dimer in the condensed phases and the dimer formation plays crucial role in both LC behavior and photoluminescent properties.

The phase transition behaviour and electro-rheological effect of liquid crystalline siloxane dimers

Symmetrical liquid crystalline dimers have been synthesised, composed of rod-like mesogenic units with polar groups and a siloxane core of varying length in the central region. All the dimers containing siloxane units have been shown to exhibit a smectic A phase, confirmed by polarising optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Rheological properties under an applied electric field were investigated by rotational rheometer. The influence of the siloxane core length on rheological properties has been investigated, and in addition the behaviour of the liquid crystalline dimers in the smectic A phase under an applied electric field has been observed by POM.

Syntheses and Physical Properties of Ferrocene Derivatives (XVI): Crystal Structure of a Liquid Crystalline Ferrocene Derivative, 5-[4-(4-Methoxyphenoxycarbonyl) Phenoxycarbonyl] Pentyl4-Ferrocenylbenzoate

The crystal structure of a monosubstituted ferrocene derivative, 5-[4-(4-methoxyphenoxycarbonyl)phenoxycarbonyl]pentyl 4-ferrocenylbenzoate was determined by the X-ray diffraction method using a single crystal. The unit cell of the crystal contained two crystallographically unequivalent molecules, A and B. The C 5 H 10 chain introduced into molecules A and B as a flexible spacer was an all-trans conformation. Both molecules were slightly bent around the ester group located at the nearest neighbor of the ferrocenylbenzoate section, but the shape of the molecules could be regarded as rodlike. This compound was a nonliquid crystalline compound; however, its structure was similar to that of the homologues, which gave rise to smectic liquid crystalline phases.

Unique molecular structure and properties of novel purple intermediates of phthalocyanine derivative

When long alkylthio-substituted phthalocyaninato copper(II) complexes, (CnS)8PcCu, were rapidly prepared in an α-diol by using our developed see-through microwave reactor and/or a conventional hot stirrer, novel purple intermediates were selectively obtained instead of the expected green complex, (CnS)8PcCu, for some specific combinations of the reaction solvent and metal salt. The reaction conditions to obtain the purple intermediates were established and the unique molecular structure was clarified for a buthylthio-substituted intermediate by X-ray single crystal structure analysis.

Synthesis and Physical Properties of Ferrocene Derivatives (XXIII) Phase Transition and Unique Molecular Structure of Monosubstituted Ferrocene Derivatives

The monosubstituted ferrocene derivatives, ω-[4-(4-methoxyphenoxycarbonyl) phenoxy]alkoxycarbonyl ferrocene, were synthesized in order to compare the liquid crystallinity to that of disubstituted ferrocene derivatives, 1,1′-bis[ω-[4-(4-methoxy-phenoxycarbonyl)phenoxy]alkoxycarbonyl]ferrocene. Some of the monosubstituted ferrocene derivatives containing relatively longer flexible spacer showed the liquid crystalline phase, nematic and/or smectic phases. The crystal structure of 2-[4-(4-methoxyphenoxycarbonyl)phenoxy]ethoxycarbonyl ferrocene was determined by X-ray diffraction method using a single crystal. The molecular structure revealed a bent structure that is almost a half of “Z” shaped molecular structure of 1,1′-bis[2-[4-(4-methoxyphenoxycarbonyl)phenoxy]ethoxycarbonyl]ferrocene.

Crystal Structure and Phase Transition Behavior of Dioctadecyldimethylammonium Chloride Monohydrate

Monohydrated single crystals of dioctadecyldimethylammonium chloride (DC18DA+ Cl−·H2O) were prepared and the crystal structure was determined to elucidate the effects of water molecules on the crystalline to liquid-crystalline phase transition behavior. From the observation during the phase transition of as-prepared single crystals by polarizing optical microscopy and powder X-ray diffractometry, we demonstrated that the water molecules are firstly melted with increasing temperature and one-dimensional ionic chains, [–{Cl2(H2O)2}2−–{(N)2}2+–] n , are merged into two-dimensional ionic layers by sliding on the (1 1 –5) planes. This rearrangement is accompanied by the formation of a smectic A like bilayer structure. In addition, the one-dimensional ionic chains are simultaneously stretched to the chain direction, and alkyl chains are interdigitated to reduce a free space within the hydrophobic unit.

Self-Organization of Gold Nanoparticles Coated with a Monolayer of Azobenzene Liquid Crystals

A gold nanoparticle having a monolayer of azobenzene liquid crystal (LC) was synthesized. The size of the gold nanoparticle obtained was 4.7 nm in average diameter, and it was soluble in common non-polar organic solvents such as toluene and dichloromethane. We confirmed that the reversible photochemical and thermal isomerization of the azobenzene could take place on the surface of the gold nanoparticles in analogy with free azobenzenes in solutions. Furthermore, a 1-dimensional self-organization of the nanoparticle was observed by transmission electron microscopy. However, a gold nanoparticle without LC molecules never showed such self-organization. Therefore, we conclude that the self-organization of the gold nanoparticle is based on the liquid crystallinity of the organic ligands attached on their surface.

Tri­cosane‐1,23‐diol

# 2001 International Union of Crystallography Printed in Great Britain ± all rights reserved In the title compound, C23H48O2, one of the hydroxy groups adopts a gauche conformation with respect to the hydrocarbon skeleton, whereas the other hydroxy group adopts a trans conformation. The molecules form a layer structure similar to that found in the smectic A phase of liquid crystals. Interand intralayer hydrogen bonds are formed in the crystal. These features are similar to those of the homologues with an odd number of C atoms. The calculated density, however, deviates from that predicted by a relation between the density and the number of C atoms in alkane,!-diols with an odd number of C atoms.

1,17-heptadecanediol

In the title compound, C(17)H(36)O(2), one of the hydroxyl groups has a gauche conformation with respect to the hydrocarbon skeleton, which is all-trans, whereas the other has a trans conformation. The molecular shape is rod-like and the compound has a rotator phase in which molecules are assured greater motional freedom, as in liquid crystals. In addition, the molecules arranged along the longest axis, b, form layers which are very similar to those of the smectic A liquid crystals.

1,21-Henicosanediol

In the molecular structure of the title compound, C(21)H(44)O(2), the hydrocarbon skeleton has an all-trans conformation. One of the terminal hydroxyl groups is also trans with respect to the skeleton, while the other is gauche. In the crystal structure, the molecules lie parallel to the b axis, forming layers with a thickness of b/2. The packing is similar to that in the smectic A phase of liquid crystals. These features are similar to those of the homologues with an odd number of C atoms, but different from those with an even number.