Columnar Liquid-Crystalline Dibenzopentacenodithiophenes by Photocyclization.
Marilia G Belarmino CabralDeise M Pereira de Oliveira SantosAhmed BentalebElizabeth A HillardRodrigo CristianoHugo GallardoFabien DurolaHarald BockPublished in: Chemistry (Weinheim an der Bergstrasse, Germany) (2016)
The twofold glyoxylic Perkin reaction of perylene-3,9-diglyoxylic acid with thiophene-diacetic acid followed by oxidative photocylization and reaction with α-branched primary alkylamines yields columnar liquid-crystalline diimides with two sulfur atoms in the condensed arene system. A broad temperature range of the hexagonal columnar mesophase is induced by racemic doubly branched alkyl chains. The HOMO and LUMO energy levels of these thiophene-derived diimides qualify them as electron donors with respect to perylene diimides.