Effects of a linking group on phase transition behavior for dimeric liquid-crystalline compounds

Abstract

We designed a homologous series of novel dimeric liquid-crystalline compounds in which two mesogenic groups are connected via a cis-2-butene-1,4-diol and investigated the phase transition behavior. Phase sequence of the symmetric dimers was similar to that of corresponding monomoeric compounds. The non-symmetric dimer possessing phenylpyrimidine and cyanobiphenyl moieties exhibited a phase sequence of Iso-SmA-Cry. The SmA phase is thought to be induced by interaction between the mesogenic moieties. On the other hand, the non-symmetric dimer possessing methoxybiphenyl and cyanobiphenyl moieties was found to show a phase sequence of Iso-N-Cry. However, a one to one mixture of the corresponding monomeric compounds did not show a liquid crystalline phase.