Heterobimetallic [NiFe] Complexes Containing Mixed CO/CN– Ligands: Analogs of the Active Site of the [NiFe] Hydrogenases
| Autor: | E. Stephen Davies, Jeremiah P. Tidey, Charlene L. Sodipo, Alexander J. Blake, Graham J. Jones, Carlo U. Perotto, Jonathan McMaster, William Lewis, Martin Schröder |
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| Rok vydání: | 2018 |
| Předmět: |
biology
Hydride Chemistry Active site 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Electrochemistry 01 natural sciences 0104 chemical sciences law.invention Inorganic Chemistry Crystallography law biology.protein Molecule Density functional theory Singlet state Physical and Theoretical Chemistry 0210 nano-technology Electron paramagnetic resonance Bimetallic strip |
| Zdroj: | Perotto, C U, Sodipo, C L, Jones, G J, Tidey, J P, Blake, A J, Lewis, W, Davies, E S, McMaster, J & Schroder, M 2018, ' Heterobimetallic [NiFe] Complexes Containing Mixed CO/CN-Ligands: Analogs of the Active Site of the [NiFe] Hydrogenases ', Inorganic Chemistry, vol. 57, no. 5, pp. 2558-2569 . https://doi.org/10.1021/acs.inorgchem.7b02905 |
| ISSN: | 1520-510X 0020-1669 |
| DOI: | 10.1021/acs.inorgchem.7b02905 |
| Popis: | The development of synthetic analogs of the active sites of [NiFe] hydrogenases remains challenging, and, in spite of the number of complexes featuring a [NiFe] center, those featuring CO and CN- ligands at the Fe center are under-represented. We report herein the synthesis of three bimetallic [NiFe] complexes [Ni(N2S2)Fe(CO)2(CN)2], [Ni(S4)Fe(CO)2(CN)2], and [Ni(N2S3)Fe(CO)2(CN)2] that each contain a Ni center that bridges through two thiolato S donors to a {Fe(CO)2(CN)2} unit. X-ray crystallographic studies on [Ni(N2S3)Fe(CO)2(CN)2], supported by DFT calculations, are consistent with a solid-state structure containing distinct molecules in the singlet (S = 0) and triplet (S = 1) states. Each cluster exhibits irreversible reduction processes between -1.45 and -1.67 V vs Fc+/Fc and [Ni(N2S3)Fe(CO)2(CN)2] possesses a reversible oxidation process at 0.17 V vs Fc+/Fc. Spectroelectrochemical infrared (IR) and electron paramagnetic resonance (EPR) studies, supported by density functional theory (DFT) calculations, are consistent with a NiIIIFeII formulation for [Ni(N2S3)Fe(CO)2(CN)2]+. The singly occupied molecular orbital (SOMO) in [Ni(N2S3)Fe(CO)2(CN)2]+ is based on Ni 3dz2 and 3p S with the S contributions deriving principally from the apical S-donor. The nature of the SOMO corresponds to that proposed for the Ni-C state of the [NiFe] hydrogenases for which a NiIIIFeII formulation has also been proposed. A comparison of the experimental structures, and the electrochemical and spectroscopic properties of [Ni(N2S3)Fe(CO)2(CN)2] and its [Ni(N2S3)] precursor, together with calculations on the oxidized [Ni(N2S3)Fe(CO)2(CN)2]+ and [Ni(N2S3)]+ forms suggests that the binding of the {Fe(CO)(CN)2} unit to the {Ni(CysS)4} center at the active site of the [NiFe] hydrogenases suppresses thiolate-based oxidative chemistry involving the bridging thiolate S donors. This is in addition to the role of the Fe center in modulating the redox potential and geometry and supporting a bridging hydride species between the Ni and Fe centers in the Ni-C state. |
| Databáze: | OpenAIRE |
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