Proton-Coupled Electron Transfer in Artificial Photosynthetic Systems

作者：Sabrina Jimena Mora, Emmanuel Odella, Gary F. Moore, Devens Gust, Thomas A. Moore, Ana L. Moore · 发表于：Accounts of Chemical Research · 年份：2018 · DOI：10.1021/acs.accounts.7b00491 · 被引用次数：155 · 研究领域：Photosynthetic Processes and Mechanisms、Porphyrin and Phthalocyanine Chemistry、Electrocatalysts for Energy Conversion

Conspectus Artificial photosynthetic constructs can in principle operate more efficiently than natural photosynthesis because they can be rationally designed to optimize solar energy conversion for meeting human demands rather than the multiple needs of an organism competing for growth and reproduction in a complex ecosystem. The artificial photosynthetic constructs described in this Account consist primarily of covalently linked synthetic chromophores, electron donors and acceptors, and proton donors and acceptors that carry out the light absorption, electron transfer, and proton-coupled electron transfer (PCET) processes characteristic of photosynthetic cells. PCET is the movement of an electron from one site to another accompanied by proton transfer. PCET and the transport of protons over tens of angstroms are important in all living cells because they are a fundamental link between redox processes and the establishment of transmembrane gradients of proton electrochemical potential, known as proton-motive force (PMF), which is the unifying concept in bioenergetics. We have chosen a benzimidazole phenol (BIP) system as a platform for the study of PCET because with appropriate substitutions it is possible to design assemblies in which one or multiple proton transfers can accompany oxidation of the phenol. In BIP, oxidation of the phenol increases its acidity by more than ten p K a units; thus, electrochemical oxidation of the phenol is associated with a proton transfer to th...