New mesogenic compounds possessing a biphenyl ester and ether moiety comprising 1,3-dimethylbarbituric acid: synthesis, characterisation and mesomorphic studies

Abstract

New substituted derivatives of 5-vinyl-1,3-dimethylbarbituric acid were synthesised and evaluated for liquid crystal properties. Two sets of molecules were prepared. One end of all the molecules possesses the 1,3-dimethylbarbituric core. The first set comprises biphenyl ethers, 4a-n and the second set biphenyl esters, 5a-g. Liquid crystalline properties were investigated by POM and DSC techniques. All the compounds exhibited enantiotropic smectic A and nematic mesophases. The LC properties were found to depend on the spacer and terminal alkoxy-chain and alkoxy-ester moiety of the molecules. Smaller alkyl chain members showed a smectic phase, while higher alkyl chain members showed a nematic phase. ARTICLE HISTORY