Long-range self-assembly of bis(imidazole)-annulated terphenyls

Abstract

In our study, we present the synthesis and characterisation of the first bis(imidazole)-annulated terphenyl disc-shaped molecules, which self-organise into columnar structures throughout long-range ordered domains during cooling from the isotropic phase. Two derivatives substituted with 3,7-dimethyloctyl and 2-decyltetradecyl substituents have been prepared. Concentration dependent UV/vis investigations indicated pronounced aggregation of both compounds in solution. The structural analysis of mechanically aligned samples revealed columnar supramolecular order with favoured helical stacking of the discs with a pitch of four molecules independent of the substituents. On the other hand, significant differences in the self-organisation during solidification from the isotropic phase were observed. The bulkier the alkyl side chains, the lower the growth rate and the higher the macroscopic order of the domains. These novel bis(imidazole)-annulated terphenyls are promising candidates for field-effect transistor applications because of the pronounced molecular packing and the formation of macroscopically aligned domains with edge-on arranged molecules.