New mesogenic homologous series of a-methylcinnamates

Compounds of a new smectogenic homologous series of alpha-methylcinnamates were prepared by condensing different 4-n-alkoxybenzoyl chloride with methoxyethyl trans-4-hydroxy-a-methylcinnamate. In this series, the first six members are non-mesogenic. n-Heptyloxy derivative exhibits monotropic smectic A phase whereas rest of the members exhibit enantiotropic smectic A mesophase. The compounds are characterized by combination of elemental analysis and spectroscopic techniques. Enthalpies of few homologues are measured by DSC techniques. Fluorescent properties are also observed. The thermal stabilities of the present series are compared with those of other structurally related mesogenic homologous series.