Effect of including extra phenylazo moiety on the mesophase behaviour of three-ring azo/ester molecules

Citation:
Mahmoud, N. E., G. R. Saad, A. A. Fahmi, and M. M. Naoum, "Effect of including extra phenylazo moiety on the mesophase behaviour of three-ring azo/ester molecules", Liquid Crystals, vol. 45, issue 11, pp. 1711 - 1722, 2018.

Abstract:

Five homologous series of the four-ring 4-substituted phenylazo phenyl 4ʹ-(4ʹ-alkoxy phenylazo) benzoates (In a–e ) were prepared and their mesophase behaviour investigated by differential scanning calorimetry (DSC) and phases identified by polarised light microscopy (PLM). Compounds prepared were structurally characterised via infrared, 1 H-NMR, mass spectroscopy, thermogravimetric and elemental analysis. Transition temperatures were first correlated with the alkoxy-chain length (n, that varies between 6, 8, 10, 14, and 16 carbons) within each homologous series, and again with the polarisability anisotropy (Δα X ) of the Ar-X bond, where X changes between CH 3 O, CH 3 , H, Br, and CN groups. Comparative studies were made to investigate the effect of introducing the extra phenyl azo moiety into the previously investigated three-ring compounds, 4-substituted phenyl 4′-(4″-alkoxyphenylazo) benzoates (IIn a–e ), 4-substituted phenylazo 4′-(4″- alkoxy phenyl) benzoates (IIIn a–e ), and 4-(4′-alkoxy phenylazo) phenyl 4″-substituted benzoates (IVn a–e ), each bear the same polar group, X, and the alkoxy group, n. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.

Notes:

Cited By :1Export Date: 6 March 2019

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