摘要:

The structure changes with the phase transition of liquid crystalline monosubstituted ferrocene derivatives, [4- ω(cholesteryloxycarbonyl)alkoxycarbonyl]phenyl]ferrocene, have been studied using a X-ray PSPC system. The results of the X-ray measurements agreed very closely with those of DSC measurements and polarizing microscopy texture observations. It was suggested that a layer structure existed in a crystal and a liquid crystal phases of the samples. The long spacing values were estimated from the PSPC data. The long spacing value of liquid crystal phase was not so much different from that obtained in our previous work. Consequently, the structure model of the liquid crystal phase previously presented can be applicable to this study. In addition to the liquid crystal structure model, the reasonable models of the crystals will be newly presented in this paper.

ISSN:1058-725X    

DOI:10.1080/10587259508041672

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The Mossbauer spectroscopy, polarization microscopy, differential scanning calorimetry and X-ray photoemission spectroscopy were used to study of structure peculiarities, dynamical and orientational properties and thermal stability of ferrocene mesogens with general formula Fe(C5H4C(CH3)=N-N=CHC6H4COOC6H4OCnH2n+1) where n = 8, 10, 12. The obtained data were compared with those for nonmesomorphic derivatives of ferrocene and organic liquid crystals.

ISSN:1058-725X    

DOI:10.1080/10587259508041673

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The interaction of N-(p-methoxy-o-hydroxybenzylidene)-p-aminopyridine(I) and N-(p-methoxy-o-hydroxybenzylidene)-m-aminopyridine(II) with certain p-alkoxybenzoic acids results in the formation of liquid crystals. Specifically, as established by optical microscopy, DSC and X-ray diffraction studies, complexes of I with short-chain acids afford nematic phases while smectic and nematic phases are induced with acids of long alkyl chain. In the complexes derived from anil II only the acids with long alkyl chains induce the formation of nematic and smectic phases.

ISSN:1058-725X    

DOI:10.1080/10587259508041674

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The synthesis and mesogenic properties of some lateral fluoro substituted 4-(trans-4-(n-propyl)cyclohexylethyl)-4′-thiomethylbiphenyls and 4-n-alkyl-4″-thiomethylterphenyls are described. Birefringence (Δn) and dielectric anisotropy (Δϵ) measurements for these compounds are also given and compared with analogous terminal chloro, cyano and methoxy compounds. It is found that the use of a terminal thiomethyl group produces compounds of intermediate Δn, Δϵ and clearing point than analogous terminal chloro, methoxy and cyano compounds. The terminal thiomethyl group is also more smectogenic than any of the other three terminal endgroups. In most cases, however, the melting points of the compounds are too high to be of practical use.

ISSN:1058-725X    

DOI:10.1080/10587259508041675

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Several new classes of low polar, low viscous and optically weak anisotropic two- and three-ring halogenated liquid crystals containing terminal group -OCF2Cl are presented. Their material properties are investigated and compared with those of other halogenated liquid crystals.

ISSN:1058-725X    

DOI:10.1080/10587259508041676

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Several new classes of mesogenic heterocyclic liquid crystals with different terminal groups are presented. Their material properties are investigated and compared with those of 2,5-disubstituted pyridine derivatives. New compounds are found to exhibit broader temperature ranges and higher transition temperatures than their analogs. Data also reported on our structural investigations (X-ray scattering) which revealed the correlation with physico-chemical properties of new 2,6-disubstituted pyridine derivatives.

ISSN:1058-725X    

DOI:10.1080/10587259508041677

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A new series of liquid crystals (LCs), benzotriazol ype which have high absorptivities to ultraviolet (UV) light within the wavelength range from 290 to 350 nm were synthesized. Their syntheses and liquid crystalline properties are reported in this paper.

ISSN:1058-725X    

DOI:10.1080/10587259508041678

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The synthesis and liquid crystal properties of eight members of an homologous series of 5-n-alkanoyl-5″ -n-alkyl-2,2′:5′,2″-terthienyls and the corresponding eight 5,5″ -di-n-alkyl-2,2′:5′,2″-terthienyls are reported. The disposition of thè three thiophene rings is sufficiently linear that suitably substituted compounds are mesomorphic, and the liquid crystal transition temperatures of related members of the two series are compared. Corresponding 5,5′-disubstituted 2,2′-bithienyls are not liquid crystalline.

ISSN:1058-725X    

DOI:10.1080/10587259508041679

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

New family of liquid crystalline compounds with high dipole moment of the general formula:

ISSN:1058-725X    

DOI:10.1080/10587259508041680

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Enantiotropic smectic B phases were observed for the homologues of 6-alkoxy-2-(2-(4-pyridyl)ethenyl) naphthalene. Chiral nematic and chiral smectic C phases were observed for mixtures with terephthalic acid mono-(2-methylbutyl) ester as chiral proton donor. These behaviors were similar to that Of 4-alkoxy-4′-stilbazole.

ISSN:1058-725X    

DOI:10.1080/10587259508041681

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor