The Effect of Methyl Group Position in Branched Alkyl Chains on the Phenolic End of 4,4′-Disubstituted Phenylbenzoates on Mesomorphic Properties and Some Optically Active Analogs as Ferroelectric Liquid Crystals

A select number of homologs of the branched chain (BC) Cs ester series: in which m = 0–3 and n = 0–2, and X = R, RO, and C9CO2 have been synthesized to study the effect of branching and the position of the branching methyl group on mesomorphic properties. This effect was also determined for the BC cyclohexane diesters: to test the generality of any trends observed in a different structural series. Mesomorphic properties of the esters were determined by hot-stage polarizing microscopy. Nematic, SA Sc and S(B?) phases in various combinations were observed. Both clearing and melting temperatures for the BC phenylbenzoates, when X = RO and C9CO2were always lower than for the analogous straight chain (SC) esters containing the same number of carbon atoms, as were in the backbone of the BC.