Rana Atanu, Mondal Biswajit, Sen Pritha, Dey Subal, Dey Abhishek
Department of Inorganic Chemistry, Indian Association for the Cultivation of Science , Kolkata, India 700032.
Inorg Chem. 2017 Feb 20;56(4):1783-1793. doi: 10.1021/acs.inorgchem.6b01707. Epub 2017 Feb 7.
Iron porphyrin complexes with second-sphere distal triazole residues show a hydrogen evolution reaction (HER) catalyzed by the Fe(I) state in both organic and aqueous media, whereas an analogous iron porphyrin complex without the distal residues catalyzes the HER in the formal Fe(0) state. This activation of the Fe(I) state by the second-sphere residues lowers the overpotential of the HER by these iron porphyrin complexes by 50%. Experimental data and theoretical calculations indicate that the distal triazole residues, once protonated, enhance the proton affinity of the iron center via formation of a dihydrogen bond with an Fe(III)-H intermediate.
含有第二配位层远端三唑残基的铁卟啉配合物在有机和水性介质中均显示出由Fe(I)态催化的析氢反应(HER)，而没有远端残基的类似铁卟啉配合物则以形式上的Fe(0)态催化HER。第二配位层残基对Fe(I)态的这种活化作用使这些铁卟啉配合物的HER过电位降低了50%。实验数据和理论计算表明，远端三唑残基一旦质子化，就会通过与Fe(III)-H中间体形成双氢键来增强铁中心的质子亲和力。
