title: [FeFe]-Hydrogenase active site models with relatively low reduction potentials: Diiron dithiolate complexes containing rigid bridges.
abstract: Three diiron dithiolate complexes containing rigid and conjugated bridges, [mu-SC(6)H(4)-2-(CO)S-mu]Fe(2)(CO)(6) (1), [2-mu-SC(5)H(3)N-3-(CO)S-mu]Fe(2)(CO)(6) (2), and the PPh(3)-monosubstituted complex [mu-SC(6)H(4)-2-(CO)S-mu]Fe(2)(CO)(5)(PPh(3)) (1-P), were prepared as biomimetic models for the [FeFe]-hydrogenase active site. The structures of complexes 1 and 2 were determined by single crystal X-ray analysis, which shows that each complex features a rigid coplanar dithiolate bridge with a 2-3 degrees deviation from the bisect plane of the molecule. The influence of the rigid bridge on the reduction potentials of complexes 1, 2 and 1-P was investigated by electrochemistry. The cyclic voltammograms of complexes 1 and 2 display large positive shifts for the primary reduction potentials, that is, 380-480mV in comparison to that of the pdt-bridged (pdt=propane-1,3-dithiolato) complex (mu-pdt)Fe(2)(CO)(6) and 160-260mV to that of the bdt-bridged (bdt=benzene-1,2-dithiolato) analogue (mu-bdt)Fe(2)(CO)(6).
authors.affiliation: State Key Laboratory of Fine Chemicals, DUT-KTH Joint Education and Research Center on Molecular Devices, Dalian University of Technology (DUT), Dalian 116012, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.forename: Mei
authors.initials: M
authors.lastname: Wang
authors.forename: Jingxi
authors.initials: J
authors.lastname: Pan
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.forename: Ning
authors.initials: N
authors.lastname: Wang
authors.forename: Licheng
authors.initials: L
authors.lastname: Sun
mesh_terms: D001665:Binding Sites; D018360:Crystallography, X-Ray; D005290:Ferric Compounds / Q000737:chemistry*; D006864:Hydrogenase; D007506:Iron-Sulfur Proteins; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010084:Oxidation-Reduction; D013055:Spectrophotometry, Infrared; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D007506:Iron-Sulfur Proteins; D013438:Sulfhydryl Compounds; C002007:dithiol-iron(III)-sulfide complex; C118830:iron hydrogenase; D006864:Hydrogenase