Synthesis and phase transition studies of new dimer compounds connected to a 1,3-dimethylbarbituric acid core

Authors : AbdulKarimTalaq MOHAMMAD, GuanYeow YEAP, Hasnah OSMAN

Pages : 443-453

Doi:10.3906/kim-1304-51

View : 20 | Download : 10

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :A series of dimeric unsymmetrical liquid crystals derived from heterocyclic 1,3-dimethylbarbituric acid exhibiting smectic A and nematic phase are reported. All compounds were prepared by the condensation of 4`-insert ignore into journalissuearticles values(R-insert ignore into journalissuearticles values(4-formylphenoxy);butoxy);biphenyl-4-carboxylate with 1,3-dimethylbarbituric acid in ethanol. The mesomorphic properties were investigated by DSC and POM, where the type of phase depends on the length of spacer alkoxy chains and the length of the terminal chain. While the SmA phase was observed upon the heating and cooling run when the spacer alkoxy chains carbon numbers increased insert ignore into journalissuearticles values(n = 6);, the N phase was observed when the length of spacer alkoxy chains increased insert ignore into journalissuearticles values(n = 8 and 10);.
Keywords : Mesogen, Schiff`s base, pyrimidine, 1, 3 dimethylbarbituric acid