Induction and control of supramolecular chirality by light in self-assembled helical nanostructures

Jisung Kim,Sanghwa Lee,Hee Chul Lee,Jinhee Lee,Myungeun Seo,Woo Young Kim,Sang Youl Kim,Hyungjun Kim,Yoon Sup Lee

doi:10.1038/ncomms7959

Abstract

Evolution of supramolecular chirality from self-assembly of achiral compounds and control over its handedness is closely related to the evolution of life and development of supramolecular materials with desired handedness. Here we report a system where the entire process of induction, control and locking of supramolecular chirality can be manipulated by light. Combination of triphenylamine and diacetylene moieties in the molecular structure allows photoinduced self-assembly of the molecule into helical aggregates in a chlorinated solvent by visible light and covalent fixation of the aggregate via photopolymerization by ultraviolet light, respectively. By using visible circularly polarized light, the supramolecular chirality of the resulting aggregates is selectively and reversibly controlled by its rotational direction, and the desired supramolecular chirality can be arrested by irradiation with ultraviolet circularly polarized light. This methodology opens a route to ward the formation of supramolecular chiral conducting nanostructures from the self-assembly of achiral molecules.

Highlights

Evolution of supramolecular chirality from self-assembly of achiral compounds and control over its handedness is closely related to the evolution of life and development of supramolecular materials with desired handedness
Amplification of the chiral information and macroscopic expression of chirality has been observed with liquid crystals, where the excess enantiomer generated by Circularly polarized light (CPL) acts as a chiral dopant and induces a chiral liquid crystalline phase[6,7,8]
By incorporating a diacetylene (DA) moiety that undergoes topochemical photopolymerization by ultraviolet (254 nm)[24,25], we demonstrate that the desired handedness can be permanently locked by circularly polarized ultraviolet light (CPUL) irradiation, which knits the self-assembled structure with covalent bonds[26,27,28]

Summary

Introduction

Evolution of supramolecular chirality from self-assembly of achiral compounds and control over its handedness is closely related to the evolution of life and development of supramolecular materials with desired handedness. By employing CPL as a light source in the self-assembly process of a TPA-containing molecule, we show that self-assembled aggregates with supramolecular chirality can be generated, driven by the helical stacking of the TPA moieties.

Results

Conclusion