Controlled aggregation of unsymmetrical amphiphilic perylene diimide derivative into nanosheets

The self-assembly behaviour of perylene diimide (PDI) derivatives has been manipulated to produce nanostructures with exceptional optoelectronic properties. The size and dimension of these aggregates determine their roles in various applications, which are determined by the structure and functionality of the PDI derivatives, including the solvent system in which self-assembly occurred. Herein, we report the synthesis of two new and distinct amphiphilic unsymmetric PDI derivatives. These PDIs contain alkyl chains of varying lengths at one of the imide positions, whereas the other imide position contains a fixed L-alanine substituent. In 90 % hexane or decalin in chloroform, these PDIs were aggregated to form ribbon-like morphologies. In contrast, in a polar solvent system comprised of mixtures of water and acetone, both PDI derivatives self-assembled differently to form distinct morphologies. As the synthesis of PDI-based two-dimensional supramolecular nanosheets has been challenging and also rarely mentioned in the literature, here, we have found that one of the PDI derivatives with long alkyl chain self-assembled to nanosheets in 90% water/acetone solvent mixture.