Homochiral Supramolecular Thin Film from Self-Assembly of Achiral Triarylamine Molecules by Circularly Polarized Light.

Changjun Park,Sang Youl Kim,Jeyoung Park,Jaechang Lim,Jinhee Lee,Woo Youn Kim,Taehyoung Kim

doi:10.3390/molecules25020402

Abstract

Here, we report the formation of homochiral supramolecular thin film from achiral molecules, by using circularly polarized light (CPL) only as a chiral source, on the condition that irradiation of CPL does not induce a photochemical change of the achiral molecules. Thin films of self-assembled structures consisting of chiral supramolecular fibrils was obtained from the triarylamine derivatives through evaporation of the self-assembled triarylamine solution. The homochiral supramolecular helices with the desired handedness was achieved by irradiation of circularly polarized visible light during the self-assembly process, and the chiral stability of supramolecular self-assembled product was achieved by photopolymerization of the diacetylene moieties at side chains of the building blocks, with irradiation of circularly polarized ultraviolet light. This work provides a novel methodology for the generation of homochiral supramolecular thin film from the corresponding achiral molecules.

Highlights

Chirality is one of the most universal and intriguing phenomena, owing to its presence in nature at all length scales, from atomic to galactic levels [1,2]
A nitro-substituted TAA compound 1 was synthesized according to the literature procedure [45]
We demonstrated the spontaneous symmetry breaking of the supramolecular assemblies composed of achiral molecules in the condition where incident light does not induce photochemical property change of the building blocks

Summary

Introduction

Chirality is one of the most universal and intriguing phenomena, owing to its presence in nature at all length scales, from atomic to galactic levels [1,2]. Supramolecular chirality has received considerable attention as it is strongly related to the homochiral systems in living organisms, such as DNA, RNA, and proteins [3]. Supramolecular chirality is generated from spontaneous symmetry breaking of supramolecular assemblies that are only composed of achiral molecules [6]. This process is especially important since an understanding of spontaneous mirror symmetry breaking mechanism can provide knowledge necessary to unveil the origins of homochirality in nature [7]

Methods

Results

Conclusion