The Effect of Carbonyl Containing Groups in the Terminal Chains on Mesomorphic Properties in Aromatic Esters and Thioesters. l. α-keto Groups on the Phenolic End

Abstract

The effect of inserting a ketone group in th α-positon of the alkyl chain on the phenolic end of 4,4'-disubstituted phenylbenzoates and di-(4'-subsituted phenyl)-trnas-cyclohexane-1, 4-dicarboxylates on mesomorphic properties as compared to those properties observed for the corresponding alkyl compounds ws determined. Transition termperatures were higher and mesophase ranges usually wider in the αketo compounds in both series. Nematic phases were observed in both series, but a strong preference for a single smectic phase predominated with this being a smectic A phase in the phenylbenzoates and a smectic C phase in the cyclohexane diesters. A variety of crystal changes and a few complex melting transitions were also observed in the cyclohexane diesters.

Keywords:

• Keywords
• Liquid crystals
• x-ray
• phenylbenzoates
• phase transistors
• transcyclohexane- 1,4-dicarboxylates