Visiblelight-driven benzofuranone-based molecular motors: tuning rotary performance from solution phase to solid state

Abstract

The advance of artificial molecular motors undoubtedly requires more versatile and tailored molecular scaffolds to achieve outstanding functions not only in the solution phase but also in the solid state. Herein, a novel type of light-driven unidirectional molecular motor based on benzofuranones was rationally designed and synthesized. Employment of the π-extension and electron donation strategies enabled several motors responsive to visible light with decent quantum yields and photoisomerizing efficiency at their photostationary states. In particular, one motor was responsive to 550 nm green light, representing the longest excitation wavelength up-to-now by one-photon excitation technique among the family of light-driven molecular motors. Moreover, the high biocompatibility and good performance under bio-environments hold these motors' enormous potential in biosciences. Importantly, these motors showed uncompromised rotary functions in condensed phases, such as soft supramolecular gel and solid polymeric films, laying a good foundation for the future design of motorized processible materials. The line of this work is assumed to promote the current focus of motor dynamics from the routine solution phase to the more practical condensed phase material systems. And the new motors explored here would offer a unique toolbox for motorists to perform the on-demand building of dynamic complexes.