Polymesomorphism in a homologous series of 2-(4-alkoxyphenyl)-5-(4-methylphenyl)pyridines

A new series of 2-(4- n -alkoxyphenyl)-5-(4-methylphenyl)pyridines (CH C H C H NC HOC H , n 1-10) (APMPP), which are teraryl compounds containing a pyridine ring in n 2 m 1 the centre position of the rigid core, was synthesized and the phase transitions of the homologues were studied using DSC measurements, polarizing optical microscopy and miscibility tests with terephthalylidene-bis-4- n -pentylaniline (TBPA). Only a nematic phase was found for the shorter alkoxy homologues with n 4. The longer alkoxy homologues with n 4 showed the sequence of enantiotropic phase transitions CrG-SmF-SmC-SmA-N-I, while a monotropic CrH phase was observed for the n 5-10 homologues. Interestingly, the polymesomorphisms appear when n is larger than 4. 3 6 4 5 3 6 4