Light-driven energy conversion reactions are an essential aspect of solar fuel technology. These reactions rely heavily on the formation of charge-separated (CS) states and electron mobility. Charge separation is commonly achieved through intersystem crossing of an excited electron in a metal complex, or by using large organic conjugates to create distance between the excited state electron and its ground state hole. Biological systems can take alternative approaches. Specifically, the copper-based protein plastocyanin serves as an electron transfer agent between photosystem I and II. Plastocyanin mediates electron transfer through conformational control, which allows it to cycle between Cu(I) and Cu(II) during the electron transfer process with a very low reorganizational energy barrier. Our bioinspired work seeks to utilize conformational control to create a long-lived CS state with energetically downhill formation and uphill charge recombination. Our highly unique twisted intramolecular charge transfer (TICT) fluorophore-functionalized dipicolylamine (dpa) copper complexes allow us to compete with current low-efficient and rare-earth metal photosensitizers. Our work has specifically focused on the synthesis and characterization of photo-activated conformationally gated Cu(I) complexes, and the study of their CS states through optical transient absorption spectroscopy and fluorescence emission spectroscopy. Benchmark studies on the functionalization of our complexes with metal catalysts for donor-acceptor systems have also established precedence for the development of heterobimetallic systems in which the conformationally-gated Cu(I) complex acts as a photosensitizer. This work will help advance and diversify research in the fields of photocatalysis and photo-driven electron transfer.

Photodriven conformational gating- applications towards solar fuel technology

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.