Photoinduced electron transfer in mechanically interlocked suit[3]ane systems

Abstract

Suitanes, a new class of two-component mechanically interlocked systems, have recently been developed. In this work, we report a detailed study of photoinduced electron-transfer processes in suit[3]anes consisting of a 3-fold symmetric pyridinium-based (HC⁶⁺·6PF₆⁻) cage and substituted benzotrithiophenes, as well as other polycyclic aromatic guests. Our analysis of the electronic properties of these complexes shows that electron transfer is favorable for complexes of HC⁶⁺·6PF₆⁻ with strong donors, such as thiatruxene, benzotrithiophenes, and benzotrifuran. The photoinduced electron transfer for these complexes occurs on the picosecond time scale. On the contrary, electron transfer does not occur in complexes of HC⁶⁺·6PF₆⁻ with benzotristhiazole and benzotrisoxazole. Our results open perspectives for the future design of mechanically interlocked systems for application in photovoltaic devices.