Mesomorphism and chemical constitution. Part VI. Certain mono- and di-anils of the benzene, diphenyl, fluorene, and fluorenone series

Gray, G. W.; Hartley, JA; Ibbotson, A.; Jones, Brynmor

doi:10.1039/jr9550004359

Cited by 63 publications

(10 citation statements)

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“…It was noted that the members of 4,4'-bis-(alkoxybenza1)-1 ,Cphenylenediamine (Gray et al, 1955;Arora et a/.. 1970;Cole et al, 1975) and phenyl-Cbenjoyloxybenzoate series (Van Meter and Klanderman, 1973a,b;Dubois and Beguin, 1978;Marcerou and Prost, 1980) show broad mesophases, and that substitution of a chlorine atom on the central aromatic ring was effective in reducing the melting points drastically while maintaining a broad mesomorphic range. For example, the melting point drops from 78°C for unsubstituted 4-p-pentylphenyl-(4-p'-pentylbenzoyloxy) benzoate to 39°C or 23°C when a 2-chloro or 3-chloro substitution is made on the central ring, while the observed nematic ranges are 102"C, 83°C and 101°C respectively.…”

Section: Introductionmentioning

confidence: 98%

X-ray scattering studies on two nematogenic p-alkylphenyl-2-chloro-4-(p-alkylbenzoyloxy)-benzoates and their mixtures

2000

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The compounds, p-n-pentylphenyl-2-chloro-4-( p-n-pentylbenzoyloxy)-benzoate and p-noctylphenyl-2-chloro-4-(p-n-heptylbenzoyloxy)-benzoat~ show a nematic phase with supercooling effect below room temperature. Marble textures are observed under a crossed polarizing microscope; however, near the N-I transition schlieren textures are observed. Mixtures of three different mole fractions of them form a nematic phase at well below room temperature. Small-angle X-ray scattering studies on all the magnetically aligned samples have been done in their entire mesomorphic ranges. X-ray diffraction patterns show that in each case the mesophaseis skewed cybotactic nematic. The average intermolecular distance is found to be N 5.10 A and the interplanar spacing of cybotactic groups is found to be less than the stereo model length of the molecules in all truns-configurations. Temperature dependence of these parameters is discussed. Orientational order parameters, (P2) and (P4), for the pure compounds and their eutectic mixture are calculated and compared with Maier-Saupe theoretical values. (P2) and (P4) values of the mixture are found to lie between those of the individual components.

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Section: Introductionmentioning

confidence: 98%

X-ray scattering studies on two nematogenic p-alkylphenyl-2-chloro-4-(p-alkylbenzoyloxy)-benzoates and their mixtures

2000

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“…In the present paper, the thermal stabilities of dibenzofuran and dibenzothiophene analogues (1) were studied from the viewpoints of the molecular geometry and the polarizability.…”

Section: R= Alkoxylmentioning

confidence: 99%

Mesomorphic Thermal Stability of 3-(4-Alkoxybenzylideneamino)-dibenzofurans and 3-(4-Alkoxybenzylideneamino)-dibenzothiophenes

Shimizu

Ikegami

Nojima

et al. 1986

Molecular Crystals and Liquid Crystals

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“…Finally, extension of a terminal n-alkyl chain substituent, in a homologous series, gives rise to a gradient in the liquid crystal transition temperatures. [13,14] A number of homologous series with ester and azo central linkages have been synthesised having different terminal groups. [15][16][17][18][19][20][21][22] The goal of the present work is to prepare a series of model compounds of the type 4-substituted phenyl 4ʹ-alkoxy phenylazo-4′-benzoates (In a-e ), in which the ester groups (OOC) in the previously investigated isomeric derivatives, [23] namely, 4-(4ʹ-alkoxy phenylazo) phenyl-4′-substituted benzoates (IIn a-e ), are inverted in the present investigation to COO.…”

Section: Introductionmentioning

confidence: 99%

The effect of inversion of the ester group on the mesophase behaviour of some azo/ester compounds

et al. 2015

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Five homologous series of 4-substituted phenyl 4′-(4″-alkoxy phenylazo) benzoates (In a-−e ) were prepared in which, within each homologous series, the length of the terminal alkoxy group varies between 8, 10, 12, 14 and 16 carbons, while the other terminal substituent, X, is a polar group that alternatively changed from CH 3 O, CH 3 , H, Br, and CN groups. Compounds prepared were characterised by infrared, mass, and H 1 -NMR spectroscopy and their mesophase behaviour investigated by differential scanning calorimetry (DSC) and polarised light microscopy (PLM). The results were discussed in terms of mesomeric and polarisability effects. Only for the lower group of compounds, I8 a-e , that showed a nematic phase, the nematic-to-isotropic transition temperatures (T N-I ) were successfully correlated to the polarisability anisotropy of bonds to the substituent X. A comparative study was made between the investigated compounds and two previously prepared isomeric groups. In the first group of isomers, 4-(4′alkoxy phenylazo) phenyl 4″-substituted benzoates (IIn a-e ), the ester groups are inverted. While in the second, 4-(4′-substituted phenylazo) phenyl 4″-alkoxy benzoates (IIIn a-e ), two modifications were made, inversion of the COO group, and exchange of the two wing substituents Keywords: phenylazo phenyl benzoates; mesophase behaviour; inversion of ester group; polarisability anisotropy

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Mesomorphism and chemical constitution. Part VI. Certain mono- and di-anils of the benzene, diphenyl, fluorene, and fluorenone series

Cited by 63 publications

References 0 publications

X-ray scattering studies on two nematogenic p-alkylphenyl-2-chloro-4-(p-alkylbenzoyloxy)-benzoates and their mixtures

X-ray scattering studies on two nematogenic p-alkylphenyl-2-chloro-4-(p-alkylbenzoyloxy)-benzoates and their mixtures

Mesomorphic Thermal Stability of 3-(4-Alkoxybenzylideneamino)-dibenzofurans and 3-(4-Alkoxybenzylideneamino)-dibenzothiophenes

The effect of inversion of the ester group on the mesophase behaviour of some azo/ester compounds

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