Gomez-Mingot Maria, Porcher Jean-Philippe, Todorova Tanya K, Fogeron Thibault, Mellot-Draznieks Caroline, Li Yun, Fontecave Marc
Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Université Pierre et Marie Curie-Paris 6, Collège de France , 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France.
J Phys Chem B. 2015 Oct 29;119(43):13524-33. doi: 10.1021/acs.jpcb.5b01615. Epub 2015 Apr 15.
Bis(dithiolene)tungsten complexes, W(VI)O2 (L = dithiolene)2 and W(IV)O (L = dithiolene)2, which mimic the active site of formate dehydrogenases, have been characterized by cyclic voltammetry and controlled potential electrolysis in acetonitrile. They are shown to be able to catalyze the electroreduction of protons into hydrogen in acidic organic media, with good Faradaic yields (75-95%) and good activity (rate constants of 100 s(-1)), with relatively high overpotentials (700 mV). They also catalyze proton reduction into hydrogen upon visible light irradiation, in combination with Ru(bipyridine)3 as a photosensitizer and ascorbic acid as a sacrificial electron donor. On the basis of detailed DFT calculations, a reaction mechanism is proposed in which the starting W(VI)O2 (L = dithiolene)2 complex acts as a precatalyst and hydrogen is further formed from a key reduced W-hydroxo-hydride intermediate.
双（二硫烯）钨配合物，即W(VI)O2 (L = 二硫烯)2和W(IV)O (L = 二硫烯)2，它们模拟了甲酸脱氢酶的活性位点，已通过循环伏安法和在乙腈中的控制电位电解进行了表征。结果表明，它们能够在酸性有机介质中催化质子电还原为氢气，法拉第产率良好（75 - 95%）且活性良好（速率常数为100 s(-1)），不过过电位相对较高（700 mV）。它们还能在可见光照射下，与作为光敏剂的Ru(联吡啶)3以及作为牺牲电子供体的抗坏血酸一起催化质子还原为氢气。基于详细的密度泛函理论计算，提出了一种反应机理，其中起始的W(VI)O2 (L = 二硫烯)2配合物作为预催化剂，氢气进一步由关键的还原态W-羟基-氢化物中间体形成。
