Enantioselective Induction of Helical Chirality in Coil-Structured Amino Acid-Based Polymers by Conjugated Molecules

Abstract

Chirality induction in aprotic polar solvents is challenging due to disrupted intermolecular interactions and the high conformational flexibility of random-coil polymers. Herein, a scalable strategy using chiral BINOL as the sole chiral source to induce helical chirality in random-coil polymers is presented. Circular dichroism (CD), ultraviolet-visible (UV– vis), and resonance Raman spectroscopy confirm that chiral BINOL effectively induces cis-transoidal helical conformations through hydrogen bonding and π–π stacking interactions. CD and circularly polarized luminescence (CPL) measurements reveal efficient chirality transfer and amplification, with mirror-image CPL signals observed at 390 nm. Resonance Raman spectra demonstrate enhanced structural order and reduced irregularities, evidenced by a blue shift and narrowed C═C Raman peak, while achiral BINOL exhibits minimal induction ability. This study highlights the mechanisms of chirality induction and CPL excitation in random-coil polymers in aprotic polar solvents, providing a versatile pathway for designing advanced materials with exceptional chiral optical and fluorescence properties.