Quadruple Helix Inversions of Liquid Crystals Orchestrated by Direct Chirality Transmission of an Intrinsically Chiral Light-Driven Molecular Machine.

Abstract

Endowing liquid crystal (LC) soft matter with stimuli-responsiveness is pivotal for programmable and dynamic photonics in the next generation of optical materials. However, suitable molecular candidates with intrinsic dynamic chirality that can twist LC helices using external stimuli in a multistate, distinct manner are still very rare. In this study, an elaborately designed intrinsically chiral molecular machine is presented with four-state dynamic chirality and mesogenic units. This design enables direct chirality transmission, leading to sequential quadruple helix inversions of the LC architecture via unidirectional rotary motion, achieving a high helical twisting power in all states. The inversion of the supramolecular helicity by near-infrared (NIR) light is demonstrated by NIR light-triggered isomerization of the molecular motor structure through an efficient radiative energy transfer pathway from upconversion nanoparticles in the LC film. Hence, these results demonstrate a unique photoresponsive LC system with high robustness, NIR light triggering, and multistate helix tunability with a fascinating potential for constructing smart optical devices.