Theoretical study on the working mechanism of a reversible light-driven rotary molecular motor

Abstract

Recent progress in the experimental design and synthesis of artifi cial light-driven molecular motors has made it possible to reverse the light-powered rotation of a molecular motor during the rotary process with multilevel control of rotary motion. With the interconversion between the photochemically generated less-stable isomers in one unidirectional rotary cycle with the stable isomers in the other cycle, the clockwise and anticlockwise rotations can be regulated with confi guration inversion at the stereogenic centre. In this work, we report theoretical calculations by using density functional theory and time-dependent density functional theory, revealing the working mechanism of the clockwise and anticlockwise rotations. Specifi cally, by locating the relevant stationary points along the excitedstate and ground-state reaction paths, the clockwise and anticlockwise rotary cycles are explored in great detail, which is of complementary importance in understanding the overall rotary process of the reversible rotation.