Binuclear Iron−Sulfur Complexes with Bidentate Phosphine Ligands as Active Site Models of Fe-Hydrogenase and Their Catalytic Proton Reduction

2007 ◽  
Vol 46 (6) ◽  
pp. 1981-1991 ◽  
Author(s):  
Weiming Gao ◽  
Jesper Ekström ◽  
Jianhui Liu ◽  
Changneng Chen ◽  
Lars Eriksson ◽  
...  
Keyword(s):  
Active Site ◽  
Phosphine Ligands ◽  
Proton Reduction ◽  
Iron Sulfur ◽  
Bidentate Phosphine ◽  
Binuclear Iron

Mono- and Bidentate Phosphine Ligands in the Palladium-Catalyzed Methyl Acrylate Dimerization

2003 ◽  
Vol 345 (3) ◽  
pp. 402-409 ◽  
Author(s):  
Jörg Zimmermann ◽  
Igor Tkatchenko ◽  
Peter Wasserscheid
Keyword(s):  
Methyl Acrylate ◽  
Phosphine Ligands ◽  
Palladium Catalyzed ◽  
Bidentate Phosphine

scholarly journals Site-selective Protonation of the One-electron Reduced Cofactor in [FeFe]-Hydrogenase

2020 ◽  
Author(s):  
Konstantin Laun ◽  
Iuliia Baranova ◽  
Jifu Duan ◽  
Leonie Kertess ◽  
Florian Wittkamp ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Active Site ◽  
Catalytic Mechanism ◽  
Ph Dependence ◽  
H2 Evolution ◽  
Proton Reduction ◽  
Ph Values ◽  
Site Selective ◽  
H2 Oxidation ◽  
Diiron Site

Hydrogenases are microbial redox enzymes that catalyze H2 oxidation and proton reduction (H2 evolution). While all hydrogenases show high oxidation activities, the majority of [FeFe]-hydrogenases are excellent H2 evolution catalysts as well. Their active site cofactor comprises a [4Fe-4S] cluster covalently linked to a diiron site equipped with carbon monoxide and cyanide ligands that facilitate catalysis at low overpotential. Distinct proton transfer pathways connect the active site niche with the solvent, resulting in a non-trivial dependence of hydrogen turnover and bulk pH. To analyze the catalytic mechanism of [FeFe]-hydrogenase, we employ in situ infrared spectroscopy and infrared spectro-electrochemistry. Titrating the pH under H2 oxidation or H2 evolution conditions reveals the influence of site-selective protonation on the equilibrium of reduced cofactor states. Governed by pKa differences across the active site niche and proton transfer pathways, we find that individual electrons are stabilized either at the [4Fe-4S] cluster (alkaline pH values) or at the diiron site (acidic pH values). This observation is discussed in the context of the natural pH dependence of hydrogen turnover as catalyzed by [FeFe]-hydrogenase.<br>

Coordination chemistry of bidentate phosphine ligands with hydrogen-bonding arms: Picket-fence rhodium complexes

Polyhedron ◽  
2014 ◽  
Vol 69 ◽  
pp. 156-159 ◽  
Author(s):  
Ilknur Babahan ◽  
James T. Engle ◽  
Nishant Kumar ◽  
Christopher J. Ziegler ◽  
Li Jia
Keyword(s):  
Hydrogen Bonding ◽  
Coordination Chemistry ◽  
Phosphine Ligands ◽  
Rhodium Complexes ◽  
Picket Fence ◽  
Bidentate Phosphine

Di-Iron Analogue of [FeFe]-Hydrogenase Active Site as a Molecular Electro-catalyst for Proton Reduction

2020 ◽  
Vol 150 (12) ◽  
pp. 3409-3414
Author(s):  
Xia Zhang ◽  
Lihong Liu ◽  
Weiming Cao ◽  
Dongjun Lv
Keyword(s):  
Active Site ◽  
Proton Reduction
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