Substituent Size Effects on the Photophysics of 1-Aryloxy-perylene Bisimide Monomers and Aggregates: A Bay-Substitution Study

This study explores the effects of 1-substitution of perylene bisimides (PBIs) with aryloxy groups on their photophysical features and aggregation equilibria. The main variables considered for this purpose were the size of the aryloxy substituent, the solvent, and the analytical concentration. In all cases, aggregate formation was monitored by observing the concentration dependence of the spectral features. Our results led us to conclude that the resulting aggregates exhibit an H-type signature and that the substituent hinders self-assembly. Compared to the reference unsubstituted homologue, the insertion of an aryloxy group proved to be an optimal strategy for modulating the photophysical features of both monomers and aggregates. A detailed discussion is presented herein.