Weber, Katharina and Krämer, Tobias and Shafaat, Hannah S. and Weyhermüller, Thomas and Bill, Eckhard and van Gastel, Maurice and Neese, Frank and Lubitz, Wolfgang (2012) A Functional [NiFe]-Hydrogenase Model Compound That Undergoes Biologically Relevant Reversible Thiolate Protonation. Journal of the American Chemical Society, 134 (51). pp. 20745-20755. ISSN 0002-7863

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Abstract

Two model compounds of the active site of [NiFe]-hydrogenases with an unusual {S2Ni(μ-S)(μ-CO)Fe(CO)2S}-coordination environment around the metals are reported. The neutral compound [Ni(xbsms)(μ-CO)(μ-S)Fe(CO)2(‘S’)], (1) (H2xbsms = 1,2-bis(4-mercapto-3,3-dimethyl-2-thiabutyl)benzene) is converted to [1H][BF4] by reversible protonation using HBF4·Et2O. The protonation takes place at the terminal thiolate sulfur atom that is coordinated to nickel. Catalytic intermediates with a protonated terminal cysteinate were suggested for the native protein but have not yet been confirmed experimentally. [1H][BF4] is the first dinuclear [NiFe] model compound for such a species. Both complexes have been synthesized and characterized by X-ray crystallography, NMR-, FTIR-, and 57Fe-Mössbauer spectroscopy as well as by electronic absorption and resonance Raman spectroscopy. The experimental results clearly show that the protonation has a significant impact on the electronic structure of the iron center, although it takes place at the nickel site. DFT calculations support the interpretation of the spectroscopic data and indicate the presence of a bonding interaction between the metal ions, which is relevant for the enzyme as well. Electrochemical experiments show that both 1 and [1H][BF4] are active for electrocatalytic proton reduction in aprotic solvents.

Item Type:	Article
Keywords:	Functional; [NiFe]-Hydrogenase; Model Compound; Biologically Relevant Reversible Thiolate Protonation;
Academic Unit:	Faculty of Science and Engineering > Chemistry Faculty of Science and Engineering > Research Institutes > Hamilton Institute
Item ID:	15511
Identification Number:	https://doi.org/10.1021/ja309563p
Depositing User:	Tobias Kraemer
Date Deposited:	15 Feb 2022 15:33
Journal or Publication Title:	Journal of the American Chemical Society
Publisher:	American Chemical Society
Refereed:	Yes
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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