Artificial light-harvesting system with sequential energy transfer in photocatalytic CP coupling based on supramolecular organic framework of triphenylamine

Abstract

Porous structures exhibit an increased access surface area, thereby promoting the efficient transportation of active oxygen species. Reinforcing the development of artificial light-harvesting systems (LHSs) with porous structured supramolecular organic frameworks (SOFs) as the energy donor can significantly enhance its photocatalytic performance, thereby facilitating efficient organic transformation via photocatalysis. In this investigation, we have successfully fabricated a supramolecular organic framework (MT-SOF) composed of cucurbit[8]uril (CB[8]) and triphenylamine derivative (MeTPPA). Because of the framework structure and large ring restriction in MT-SOF, its fluorescence emission shows a significant increase when compared to that of the individual MeTPPA molecule. By harnessing the remarkable fluorescence emission characteristics of MT-SOF, it was employed as an energy donor in conjunction with Sulforhodamine 101 (SR101) and Cyanine 5 (Cy5) as acceptors to fabricate sequential energy transfer LHS. MT-SOF-SR101-Cy5 has the ability to act as a photosensitizer, facilitating the CP bond coupling with broad applicability. It is important to mention that when compared to MeTPPA, MT-SOF and MT-SOF-SR101, the photocatalytic performance of MT-SOF-SR101-Cy5, featuring continuous two-step energy transfer, shows significant improvement, which can be attributed to the porous structure of MT-SOF and the increased efficiency in generating superoxide anion radical (O₂⁻).