Stimuli-responsive molecular systems that mimic the highly complex and dynamic functions found in nature (e.g. allostericity, signalling, motion and transport) are receiving major interest and will form the basis of future nanomachines. In this context, molecular switches and motors that are activated by light are emerging as powerful tools to control the properties of materials as well as biological functions. Light offers the advantage that it can be applied with high spatiotemporal precision without producing waste.
In this presentation, synthetic systems in which control of motion at the molecular level is coupled to specific functions will be discussed. Particular focus is on the use of light-driven molecular rotary motors as multi-state switches for the modulation of receptor-ligand interactions and self-assembly processes. Finally, strategies to regulate the speed of rotation and to red-shift the excitation wavelength of these molecular motors are illustrated.