Biomimetic model for [FeFe]-hydrogenase: asymmetrically disubstituted diiron complex with a redox-active 2,2′-bipyridyl ligand

Roy, Souvik, Groy, Thomas L. and Jones, Anne K. (2013) Biomimetic model for [FeFe]-hydrogenase: asymmetrically disubstituted diiron complex with a redox-active 2,2′-bipyridyl ligand. Dalton Transactions, 42 (11). p. 3843. ISSN 1477-9226

Full content URL: https://doi.org/10.1039/C2DT32457A

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Item Type:Article
Item Status:Live Archive

Abstract

[FeFe]-hydrogenases feature a unique active site in which the primary catalytic unit is directly coordinated via a bridging cysteine thiolate to a secondary, redox active [4Fe4S] unit. The goal of this study was to evaluate the impact of a bidentate, redox non-innocent ligand on the electrocatalytic properties of the (μ-S(CH2)3S)Fe2(CO)4L2 family of [FeFe]-hydrogenase models as a proxy for the iron–sulfur cluster. Reaction of the redox non-innocent ligand 2,2′-bipyridyl (bpy) with (μ-S(CH2)3S)Fe2(CO)6 leads to substitution of two carbonyls to form the asymmetric complex (μ-S(CH2)3S)Fe2(CO)4(κ2-bpy) which was structurally characterized by single crystal X-ray crystallography. This complex can be protonated by HBF4·OEt2 to form a bridging hydride. Furthermore, electrochemical investigation shows that, at slow scan rates, the complex undergoes a two electron reduction at −2.06 V vs. Fc+/Fc that likely involves reduction of both the bpy ligand and the metal. Electrocatalytic reduction of protons is observed in the presence of three distinct acids of varying strengths: HBF4·OEt2, AcOH, and p-TsOH. The catalytic mechanism depends on the strength of the acid.

Keywords:Biomimetic models, Ligands, Hydrogenase
Subjects:C Biological Sciences > C720 Biological Chemistry
F Physical Sciences > F100 Chemistry
F Physical Sciences > F161 Organometallic Chemistry
Divisions:College of Science > School of Chemistry
ID Code:40683
Deposited On:16 Apr 2020 15:54

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