New mesogenic homologous series of alpha-methylcinnamates

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