Influence of bidentate phosphine ligands on the chemistry of [FeFe]-hydrogenase model: insight into molecular structures and electrochemical characteristics |
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Authors: | Mohammad El-khateeb Hassan Abul-Futouh Hadil Alshurafa Helmar Görls Wolfgang Weigand |
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Institution: | 1. Chemistry Department, Jordan University of Science and Technology, Irbid, 22110 Jordan;2. Department of Pharmacy, Al-Zaytoonah University of Jordan, P.O. Box 130, Amman, 11733 Jordan;3. Institut für Anorganische und Analytische Chemie, Friedrich-Schiller-Universität Jena, Humbodt-Straße 2, Jena, 07743 Germany |
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Abstract: | Substitution of carbonyl ligands of the hydrogenase model complex Fe2(μ-SeCH2CH(Me)CH2Se-μ)(CO)6] ( A ), by 1,1′-bis (diphenylphosphino)ferrocene (dppf), 1,2-bis (diphenylphosphino)benzene (dppbz) or 1,2-bis (diphenylphosphino)acetylene (dppac) is investigated. It is found that the reaction product depends on the diphosphine used. In the case of dppf, the product is an intramolecular bridged disubstituted complex Fe2{μ-SeCH2CH(Me)CH2Se-μ}(CO)4{μ,κ1,κ1(P,P)-dppf}] ( 1 ), while the dppac-reaction produces an intermolecular bridged tetra-iron model Fe2{μ-SeCH2CH(Me)CH2Se-μ}(CO)5]2{μ,κ1,κ1(P,P)-dppac} ( 2 ). However, the dppbz-reaction gives Fe2{μ-SeCH2CH(Me)CH2Se-μ}(CO)4{κ2(P,P)-dppbz}] ( 3 ) in which the dppbz ligand is bonded to one Fe atom in a chelated manner. The newly prepared complexes ( 1 – 3 ) have been characterized by elemental analysis, IR, 1H-, 13C{H}-, 31P{H}-, 77Se{H}-NMR spectroscopy and X-ray structure determination. The electrochemical behavior of 2 and 3 , in absence and presence of acid, is described by cyclic voltammetric measurements in CH2Cl2. |
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Keywords: | Diselenolates electrochemistry hydrogen production iron substitution |
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