Development of photoresponsive supramolecular machines inspired by biological molecular systems

In the growing research area on molecular machinery, light is one of the attractive and useful stimuli source to operate synthetic molecular machines, since light allows selective operation of photoresponsive moieties without additives. We have proposed a new approach to design of photoresponsive molecular machines by interlocking mechanical motions between photoresponsive and movable units through covalent and non-covalent bonds. This approach is inspired by biological molecular machines consisting of multiple protein subunits, and potentially useful for construction of giant mechanical systems. In this review, we will introduce our concepts of the molecular design with several successful examples as well as their applications for controlling chemical events, and also glance at a semi-biological molecular machine controllable by light, which reveals a potential of biological systems for development of elaborate molecular devices.