Transition temperature engineering of octaalkoxycarbonyl phthalocyanines

Abstract

We have described a simple approach to the transition temperature engineering in metal-free mesogenic octaalkoxycarbonyl phthalocyanines Pc(COOR)8. The method is based on the esterification of a common octaacid precursor with binary mixtures of alcohols. Variation of the length of alkyl chain and the ratio of components in the starting mixtures of alcohols resulted in phthalocyanines comprising multiple components, yet with well-defined and reproducible composition that was reflected in well-defined and reproducible thermotropic properties. Linear dependence between isotropization temperatures and average length of alkyl chains in Pc(COOR)8 was demonstrated.