Mesomorphic behaviour of new azomethine liquid crystals having terminal bromo substituent

A homologous series of azomethine esters,4-n-alkanoyloxybenzylidene-4＇-bromoanilines possessing even number of carbon atoms at the terminal alkanoyloxy chain（C_（n-1）H_（2n-1）COO- n = 8,10,12,14,16,18） was synthesized and characterized.Whilst n-octanoyloxy to n-dodecanoyloxy derivatives exhibited enantiotropic smectic A and smectic B phases,n-tetradecanoyloxy to n-octadecanoyloxy derivatives possessed enantiotropic smectic A and monotropic smectic B properties.n-Decanoyloxy derivatives demonstrated the optimum exhibition for both smectic A and smectic B phases.It was found that the length of terminal alkanoyloxy chain has an influence on mesomorphic properties.