Study of mesomorphism and its relation to molecular structure with special reference to central bridges viz. -COO- and -CH=CH-COO- of the homologous series
摘要:
Two ester homologous series of mesogens, viz., Methyl-p-(p '-n-alkoxy benzoyloxy) cinnamates (X) and Methyl-p-(p '-n-alkoxy cinnamoyloxy) cinnamates (Y) being structurally similar are discussed. Both (X) and (Y) differ in respect of central bridges linking two phenyl rings. Only enantiotropic nematogenic character is observed without exhibition of any smectic character by all members of series (X) and (Y). Thermal stability of series (X) is relatively low as compared to (Y), but nematogenic mesophase lengths are of reverse order. Solid-nematic/solid-isotropic and nematic-isotropic transition curves in the phase diagrams behave in normal manner.
and their hypolipidemicactivities were evaluated in a screening system with rats. Cinnamic acids, alpha-methylcinnamic acids, and their various esters with a higher p-alkoxy substituent were found to possess hypolipidemicactivities higher than or comparable to that of clofibrate. The proper length (C12--C16) and the para position of the alkoxy substituent seem to be essential for activity. Chloroethyl
Mesomorphism and flexibility of alkyl chains in chalcone esters
作者:N. R. Muniya、V. R. Patel
DOI:10.1080/15421406.2016.1221989
日期:2016.10.12
Schlieren. Cr-N/I transitioncurve adopts a zigzag path in a normal manner with overall descending behaviors. The N-I transitioncurve exhibits a sharp and shorter odd-even effect from C3 to C6 and it diminishes from and beyond C6 for higher homologs of longer n-alkyl chain (R) in more or less or negligible deviating manner from normal descending tendency. Thermal stability for the nematic is 116.4°C and
The effect of geometrical shape and molecular rigidity on mesomorphism
作者:Priya K. Patel、R. R. Shah
DOI:10.1080/15421406.2016.1190509
日期:2016.9.21
nonlinear homologousseries RO‒C6H4‒CH˭CH‒COO‒C6H4 (meta) ‒CO‒CH˭CH‒C6H4‒OC12H25(n) (para) consisting of three phenyl rings, two central bridges ‒CH˭CH‒COO‒ and ‒CO‒CH˭CH‒ as well as ‒OR and ‒OC12H25(n) as flexible and constant terminal end groups respectively. The object in view is aimed to understand and establish the effect of molecularstructure on LC properties of nonlinear inverted “V” shaped
Study of a new homologous series of liquid crystals: Isopropyl-p-(p<sup>/</sup>-n-alkoxy cinnamoyloxy) cinnamates
作者:B. B. Jain、U. H. Jadeja、V. S. Sharma、R. B. Patel
DOI:10.1080/15421406.2015.1073567
日期:2016.1.22
homologue, and follows a zigzag path of rising and falling values as the series is ascended. Nematic–isotropictransition curve shows descending tendency as series is ascended in a normal manner with exhibition of odd-even effect. Smectic mesophase does not appear even in the monotropic condition. Phase transitiontemperatures are determined by hot stage polarizing microscope. Analytical data support
Mesomorphism Dependence on Terminally Substituted End Group
作者:Rajesh B. Marathe、A. V. Doshi
DOI:10.1080/15421406.2014.990748
日期:2015.12.12
A novel homologous series of liquid crystalline substances has been synthesized and studied with a view to understanding and establishing the relation between liquid crystal properties and molecular structure. The novel ester series consists of eleven enantiotropically smectogenic homologous without exhibition of nematogenic property. Transition temperatures were determined with an optical polarizing