Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.237, 193-205, 1993
Synthesis and Mesomorphic Properties of Some Aromatic Esters Containing 2-Butyl, 2-Octyl and 2-Methylbutyl Moieties in the Terminal Chains
A variety of esters/thioesters (Z=O/S) with terminal chains containing sterically hindered branched chains containing CH(Me)Et, [GRAPHICS] CH(Me)C6H13 and CH2CH2CH(Me)Et in either the X or Y chain attached to the benzene ring through an ether oxygen atom, (CH2)nCO2- or (CH2)nOCO- with n = 0-2 and the other chain being R, RO, RCO, RCO2, or ROCO were synthesized as possible new ferroelectric liquid crystals or dopants in mixtures of branched chain phenylbenzoates and phenylthiobenzoates. The main goal was to incorporate substituents that favor larger spontaneous polarization than observed for the thioesters with Z = S and Y = CH2CH2CH(Me)Et and determine if these compounds would have the desired N, S(A) and Sc properties. The best properties were observed in the esters with Y = OCOCH(Me)Et. Some cyclohexane diesters and lateral substituted esters containing these branched chains were also prepared. Two branched chain esters/thioesters with X = CN were synthesized as potential cholesteric blue phase materials. These compounds were prepared using slightly modified procedures reported earlier. Comparisons in mesomorphic properties are discussed.
Keywords:FERROELECTRIC LIQUID-CRYSTALS;OPTICALLY-ACTIVE ANALOGS;BRANCHED ALKYL CHAINS;METHYL-GROUP POSITION;PHENOLIC END;4;4’-DISUBSTITUTED PHENYLBENZOATES;HOMOLOGOUS SERIES;SPONTANEOUS POLARIZATION;ACYLOXY GROUPS;ACID END