摘要:

Novel CT complexes derived from 4-alkylamino-TEMPO radical and 2,4,6,8-tetracyanoazulene have been prepared. Curie-Weiss behavior has been observed in the magnetic susceptibility of each complex with antiferromagnetic spin-spin interactions in the low temperature region on one hand and rather high conductivity has been found in the electrical conductivity of each complex with semiconducting behavior on the other hand.

ISSN:1058-725X    

DOI:10.1080/10587250008024790

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

4-octyloxybenzoic acid, C15H22O3, crystallises in the triclinic space groupP1with lattice parametersa= 12.207(3)Å,b= 13.424(3)Å,c= 4.8666(16)Å, α = 91.26(2)°, β = 91.46(3)°, γ = 116.756(14)°,V= 711.4(3)Å3, Z = 2,D(cal)= 1.169 Mg/m3, μ = 0.08 mm-1,F000= 272, GooF = 0.940,R1 = 0.0563 andwR2 = 0.1512.

ISSN:1058-725X    

DOI:10.1080/10587250008024791

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

It was shown that the low-frequency edge of the exciton absorption band of J-aggregates of l-methyl-l′-octadecyl-2,2′-cyanine iodide (analogue of PIC) experiences a change from Gaussian to Lorentzian in frozen, binary DMF-H2O solution, upon decrease of water concentration. In a Langmuir-Blodgett film, the shape of the low-frequency edge of exciton absorption band was neither Gaussian nor Lorentzian, in contrast. A model of diagonal and off-diagonal disorder in the molecular chains is proposed to explain the observed band shapes, based on selective solvation of amphiphilic molecules by water and DMF solvent molecules.

ISSN:1058-725X    

DOI:10.1080/10587250008024792

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The rheological behaviour of two different molecular weights of a thermotropic liquid crystalline cellulose derivative, acetoxypropylcellulose (APC), at T=120°C, has already been reported [1]. In this work we present the temperature dependence of the rheological properties of two molecular weights of APC.

ISSN:1058-725X    

DOI:10.1080/10587250008024793

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Use of chiral dopant in binary mixtures to induce ferroelectricity/chiral nematic phase is an easier way than the synthesis of ferroelectric or chiral nematic materials. Number of researchers have tried to induce chirality in the achiral mesogens by doping it with naturally occuring chiral compounds or their derivatives. Few binary systems were studied where one of the components is the non-mesogenic chiral dopant. In almost all the systems studied cholesteric phase (N) is induced with lowering in transition temperatures. The study provides means to induce chirality in mesogenic system by doping it with the derivative of naturally occurring chiral menthol.

ISSN:1058-725X    

DOI:10.1080/10587250008024794

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Complexation of non-mesomorphic dithiooxamide ligands to Pt(II) leads to square planar complexes which exhibit mesomorphic properties. The synthesis of these complexes was accomplished in three steps: the formation of bisamides, starting from conveniently substituted anilines, their conversion into dithiooxamides and the reaction of these sulfur derivatives with [PtCl2(dmso)2]. Four, eight and twelve-chained complexes were obtained and their behaviour as potentially mesomorphic material was studied. The eight-chained complexes21(n= 12–16) and the twelve-chained complexes22(n= 8,11,13) exhibit columnar mesophases which have been characterised by optical microscopy, X-ray scattering and related miscibility studies.

ISSN:1058-725X    

DOI:10.1080/10587250008024795

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A new series of mesogenic Schiff′s base esters, 4-(4′-n-Alkoxybenzoyloxy) 3-methoxy benzylidene 2”-aminonaphthalenes has been synthesized. The synthesized compounds were characterised by elemental analysis and standard spectroscopic methods.

ISSN:1058-725X    

DOI:10.1080/10587250008024796

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

X-ray diffraction study of two liquid crystalline 2,5-disubstituted 1,3,4-oxadiazole and 1,3,4-thiadiazole derivatives reveals the existence of a partially bilayered smectic Ad phase in the terminally bromo substituted derivatives, with the lower level of molecular overlapping in the formation of the dimer and more pronounced smectic fluctuations on the dimeric density wave observed for the former compound.

ISSN:1058-725X    

DOI:10.1080/10587250008024797

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The interaction of light with Cholesteric Liquid Crystals (CLC) in the presence of time dispersion, magnetooptical activity and absorption is considered. The magnetooptical activity leads to the waves irreversibility, i.e. to the absence of center of symmetry for the surface of wave vectors and other surfaces, characterizing the direction dependence of optical properties (the nonequivalency of the forward and backward directions of propagation occurs). The waves irreversibility effects in CLC and their influence on the geometry of the Bragg reflection are considered.

ISSN:1058-725X    

DOI:10.1080/10587250008024798

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

In the present paper the spectral-structural-phase correlations in a series of the 4-cyano-4′-n-alkoxybiphenyles (n= 3 - 8) are studied. The analysis of Q(C≡N) band behaviour in the solid crystal (SC), liquid crystal (LC), isotropic liquid (IL) and hexane solution is carried out. The mechanism of intradimer energy transfer which explains the Q(C≡N) band breadth in the LC and IL phases is proposed.

ISSN:1058-725X    

DOI:10.1080/10587250008024799

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor