The Chirality Induction and Modulation of Polymers by Circularly Polarized Light

Guang Yang,Jingang Hu,Michiya Fujiki,Gang Zou,Siyu Zhang

doi:10.3390/sym11040474

Abstract

Chirality is a natural attribute nature of living matter and plays an important role in maintaining the metabolism, evolution and functional activities of living organisms. Asymmetric conformation represents the chiral structure of biomacromolecules in living organisms on earth, such as the L-amino acids of proteins and enzymes, and the D-sugars of DNA or RNA, which exist preferentially as one enantiomer. Circularly polarized light (CPL), observed in the formation regions of the Orion constellation, has long been proposed as one of the origins of single chirality. Herein, the CPL triggered asymmetric polymerization, photo-modulation of chirality based on polymers are described. The mechanisms between CPL and polymers (including polydiacetylene, azobenzene polymers, chiral coordination polymers, and polyfluorene) are described in detail. This minireview provides a promising flexible asymmetric synthesis method for the fabrication of chiral polymer via CPL irradiation, with the hope of obtaining a better understanding of the origin of homochirality on earth.

Highlights

Homochirality is one of the most valuable aspects of science and is an essential molecular characteristic of terrestrial life [1,2,3,4]
In 1929, Kuhn conducted an experiment by irradiating a racemic organic molecule solution with circularly polarized light (CPL) for the first time, and the results demonstrated that CPL could successfully induce the asymmetric photolysis of organic molecules [36]
This review review provides provides a promising flexible asymmetric synthesis synthesismethod methodforfor preparation of chiral polymers ontechnology, CPL technology, thethe preparation of chiral polymers basedbased on CPL

Summary

Introduction

Homochirality is one of the most valuable aspects of science and is an essential molecular characteristic of terrestrial life [1,2,3,4]. Scientists have reported several methods to synthesize chiral materials, such as the use of chiral solvents or templates, polymerization with chiral monomers, substituted achiral polymers with a chiral center, supramolecular self-assembly and circularly polarized light (CPL) irradiation. The utilization of CPL irradiation technology incircularly areas including polarized light (CPL) irradiation Compared with these methods, circularly polarized light (CPL), the chirality induction, transference and amplification of liquid crystal or polymers would be of great proposed to be one of the origins of homochirality in nature, is regarded as an important tool to value especially in asymmetric reaction. 5).inInterestingly, The DA units in the crystal phase could not form helical chains due to the restriction of the crystal lattice, while in the lamellar columnar mesophase, the molecular motion of the hydrogen-bonded complex was relatively free, and the external CPL could effectively direct the screw orientation of the final PDA chains [63]. This work offered a new method for the fabrication of helical polymers in the liquid crystal phase

TheReference mechanism of formation helical films inSociety theSociety

Enantioselective

Conclusions