THE SYNTHESIS AND LIQUID-CRYSTAL PROPERTIES OF CERTAIN 5,5''-DISUBSTITUTED 2,2' 5',2''-TERTHIENYLS/

A preliminary account of the synthesis and liquid crystal properties o f representative members of an homologous series of 5-alkanoyl-5 ''-al kyl-2,2':5',2 ''-tertbienyls and the analogous 5,5 ''-di-alkyl-2,2':5' ,2 ''-terthienyls is given. The disposition of the three thiophene rin gs renders the molecular geometry sufficiently anisotropic that suitab ly substituted compounds are mesomorphic, and the liquid crystal trans ition temperatures of corresponding members of the two series are comp ared. The related 5, 5'-disubstituted 2, 2'-bithienyl derivatives are not mesomorphic.