A Synthesis and Mesophase behaviour of Homologous Series: 4-(4’-n-alkoxy cinnamoyloxy) Azo 4”-bromo-3”-methyl benzene with Terminal Methyl and bromo group

A new homologous series 4-(4’-n-alkoxy cinnamoyloxy) Azo 4”-bromo-3”-methyl benzene was synthesized with a view to understand and establish the relation between mesogenic properties and structure of molecules. Ethyl to hexadecyl all twelve homologues are enantiotropically nematogenic. None of the homologues exhibited a smectogenic mesophase. No odd–even effect was observed in the transition curve. The average thermal stability was observed to be 127.9°C and the nematogenic mesophase ranged from 8.0°C to 16.0°C. Thus, the series was found to be of a low ordered melting type with moderate nematogenic range. Analytical data confirmed the structure of the compounds, and the mesomorphism was identified by optical microscopy. The mesogenic properties were compared with structurally similar compounds.