Department Functional Interfaces, Leibniz Institute of Photonic Technology Jena (IPHT), Albert-Einstein-Straße 9, 07745, Jena, Germany.
Department of Inorganic Chemistry I, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
Angew Chem Int Ed Engl. 2019 Sep 9;58(37):13140-13148. doi: 10.1002/anie.201907247. Epub 2019 Aug 19.
Understanding photodriven multielectron reaction pathways requires the identification and spectroscopic characterization of intermediates and their excited-state dynamics, which is very challenging due to their short lifetimes. To the best of our knowledge, this manuscript reports for the first time on in situ spectroelectrochemistry as an alternative approach to study the excited-state properties of reactive intermediates of photocatalytic cycles. UV/Vis, resonance-Raman, and transient-absorption spectroscopy have been employed to characterize the catalytically competent intermediate [(tbbpy) Ru (tpphz)Rh Cp*] of [(tbbpy) Ru(tpphz)Rh(Cp*)Cl]Cl(PF ) (Ru(tpphz)RhCp*), a photocatalyst for the hydrogenation of nicotinamide (NAD-analogue) and proton reduction, generated by electrochemical and chemical reduction. Electronic transitions shifting electron density from the activated catalytic center to the bridging tpphz ligand significantly reduce the catalytic activity upon visible-light irradiation.
理解光驱动的多电子反应途径需要识别和光谱表征中间体及其激发态动力学,由于中间体的寿命很短,这是非常具有挑战性的。据我们所知,本文首次报道了原位光谱电化学作为一种替代方法来研究光催化循环中反应性中间体的激发态性质。采用 UV/Vis、共振拉曼和瞬态吸收光谱来表征[(tbbpy)Ru(tpphz)RhCp*]的催化活性中间体[(tbbpy)Ru(tpphz)Rh(Cp*)Cl]Cl(PF6)(Ru(tpphz)RhCp*),该光催化剂用于催化烟酰胺(NAD 类似物)的加氢和质子还原,通过电化学和化学还原生成。电子跃迁将电子密度从活化的催化中心转移到桥联的 tpphz 配体上,这显著降低了可见光照射下的催化活性。