Molecular arrangement of mesogenic disc-like compounds : the hexa-n-alkoxy and hexa-n-alkanoyloxy triphenylenes

Abstract

A theoretical study of homologous series of triphenylene hexaesters and hexaethers, disc-like mesogenic molecules, has been undertaken with semi-empirical methods. Preferential conformations of an isolated molecule, a pair of molecules and a set of molecules have been established For butyl and further homologues, hexaesters give irregular columns, resulting in piled pairs, with distances d and d' equal to 3.75 and 4.45 Å between neighbouring aromatic cores. On the other hand hexaethers give regular columns (d ≃ 3.28 Å) of helicoidal type with a pitch equal to 14 Å. These results are in agreement with data from X-ray diffraction on the mesophase