Self-assembly of pyridinium-functionalized anthracenes: molecular-skeleton-directed formation of microsheets and microtubes

Abstract

Two amphiphilic regioisomers, 9-AP (1-[11-(9-anthracenylmethoxy)-11-oxoundecyl]pyridinium bromide), and 2-AP (1-[11-(2-anthracenyl methoxy)-11-oxoundecyl]pyridinium bromide), were synthesized and their assembly behaviors were studied. Due to the anisotropic features of the anthracene structure, different substituted positions on the anthracene ring lead 9-AP and 2-AP to adapt "shaver" and "spatula"-like molecular shapes, respectively, which consequently dictate the structure of their final assemblies. While "shaver"-shaped 9-AP assembled into microsheets, driven by π-π interactions, "spatula"-shaped 2-AP assembled into microtubular structures, promoted primarily by charge-transfer interactions.

Keywords: amphiphiles; charge transfer; molecular engineering; pi-pi interactions; self-assembly.