Department of Chemistry , KTH Royal Institute of Technology , 10044 Stockholm , Sweden.
State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, DUT-KTH Joint Education and Research Center on Molecular Devices, Dalian University of Technology (DUT) , 116024 Dalian , China.
J Am Chem Soc. 2019 Apr 10;141(14):5565-5580. doi: 10.1021/jacs.8b12862. Epub 2019 Mar 28.
A water-oxidation catalyst with high intrinsic activity is the foundation for developing any type of water-splitting device. To celebrate its 10 years anniversary, in this Perspective we focus on the state-of-the-art molecular water-oxidation catalysts (MWOCs), the Ru-bda series (bda = 2,2'-bipyridine-6,6'-dicarboxylate), to offer strategies for the design and synthesis of more advanced MWOCs. The O-O bond formation mechanisms, derivatives, applications, and reasons behind the outstanding catalytic activities of Ru-bda catalysts are summarized and discussed. The excellent performance of the Ru-bda catalyst is owing to its unique structural features: the distortion induced 7-coordination and the carboxylate ligands with coordination flexibility, proton-transfer function as well as small steric hindrance. Inspired by the Ru-bda catalysts, we emphasize that the introduction of negatively charged groups, such as the carboxylate group, into ligands is an effective strategy to lower the onset potential of MWOCs. Moreover, distortion of the regular configuration of a transition metal complex by ligand design to generate a wide open site as the catalytic site for binding the substrate as an extra-coordination is proposed as a new concept for the design of efficient molecular catalysts. These inspirations can be expected to play a great role in not only water-oxidation catalysis but also other small molecule activation and conversion reactions involving artificial photosynthesis, such as CO reduction and N fixation reactions.
具有高本征活性的水氧化催化剂是开发任何类型的水分解装置的基础。值此十周年之际，在这篇观点文章中，我们重点介绍了最先进的分子水氧化催化剂（MWOCs），Ru-bda 系列（bda=2,2'-联吡啶-6,6'-二羧酸），为设计和合成更先进的 MWOCs 提供策略。总结和讨论了 O-O 键形成机制、衍生物、应用以及 Ru-bda 催化剂卓越催化活性的背后原因。Ru-bda 催化剂的优异性能归因于其独特的结构特征：扭曲诱导的 7 配位和具有配位灵活性、质子传递功能以及小空间位阻的羧酸配体。受 Ru-bda 催化剂的启发，我们强调将带负电荷的基团（如羧酸根）引入配体是降低 MWOCs 起始电位的有效策略。此外，通过配体设计扭曲过渡金属配合物的规则构型，以产生作为结合底物的催化位点的宽阔开口作为额外配位，被提出作为设计高效分子催化剂的新概念。这些启示不仅有望在水氧化催化中发挥重要作用，而且在涉及人工光合作用的其他小分子活化和转化反应中也发挥重要作用，例如 CO 还原和 N 固定反应。
