A Model of a Closed Cycle of Water Splitting Using ansa-Titanocene(III/IV) Triflate Complexes

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• 作者：Christian Godemann ; Dirk Hollmann ; Monty Kessler ; Haijun Jiao ; Anke Spannenberg ; Angelika Brückner ; Torsten Beweries
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：December 30, 2015
• 年：2015
• 卷：137
• 期：51
• 页码：16187-16195
• 全文大小：530K
• ISSN：1520-5126

文摘

A series of ansa-titanocene triflate complexes are described as model compounds for the elementary steps of light-driven overall water splitting. Titanocene(III) triflate complexes are readily obtained by reaction of a titanocene source with Yb(OTf)₃. Subsequent reactions with water and with/without TEMPO as hydrogen scavenger are studied. The as-obtained titanocene(IV) compounds can be photoreduced to give titanocene(III) triflate complexes, which can undergo further hydrolysis to form a closed catalytic cycle of water splitting. No further degradation of the photoreduced species was observed because of the presence of the OTf group. The stability of the system was evaluated in an experiment with high concentrations of water and TEMPO. X-ray crystallography on all titanocene complexes, EPR and NMR spectroscopy, and DFT were used to support our observations.