Columnar Mesophases and Organogels Formed by H-Bound Dimers Based on 3,6-Terminally Difunctionalized Triphenylenes

Abstract

A series of triphenylene (TP) compounds—denoted 3,6-THTP-DiCnOH—bearingfour hexyloxy ancillary chains and two variable-length alkoxy chains terminally functionalizedwith hydroxyl groups have been synthesized and characterized. The shorterhomologs revealed mesogenic characteristics, giving rise to thermotropic mesophasesin which π-stacked columns of H-bound dimers self-organize yielding superstructures.Molecular-scale models are proposed to account for their structural features. The threestudied compounds yielded supramolecular gels in methanol; their ability to gelify higheralcohols was found to be enhanced by the presence of water. The intermediate homologalso gelled n-hexane. Compared to their isomeric 2,7-THTP-DiCnOH analogs, the3,6-derivatives showed a higher tendency to give rise to LC phases (wider thermal ranges)and a lower organogelling ability (variety of gelled solvents, lower gels stabilities). The overallresults are analyzed in terms of different kinds of competing H-bonds: intramolecular,face-to-face dimeric, lateral polymeric, and solvent–TP interactions.