title: Active-site models for iron hydrogenases: reduction chemistry of dinuclear iron complexes.
abstract: Reduction of Fe2(mu-S2C3H6)(CO)6 (1) in tetrahydrofuran with 1 equiv of decamethylcobaltocene (Cp*2Co) affords a tetranuclear dianion 2. The IR spectra of samples of 2 in solution and in the solid state exhibit a band at 1736 cm(-1), suggestive of the presence of a bridging carbonyl (CO) ligand. X-ray crystallography confirms that the structure of 2 consists of two Fe2 units bridged by a propanedithiolate moiety formulated as [Fe2(mu-S2C3H6)(CO)5(SCH2CH2CH2-mu-S)Fe2(mu-CO)(CO)6](2-). One of the Fe2 units has a bridging CO ligand and six terminal CO ligands. The second subunit exhibits a bridging propanedithiolate moiety. One CO ligand has been replaced by a terminal thiolate ligand, replicating the basic architecture of Fe-only hydrogenases. The reduction reaction can be reversed by treatment of 2 with 2 equiv of [Cp2Fe][PF6], reforming complex 1 in near-quantitative yield. Complex 2 can also be oxidized by acids such as p-toluenesulfonic acid, regenerating complex 1 and forming H2.
authors.affiliation: Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA.
authors.forename: Inigo
authors.initials: I
authors.lastname: Aguirre de Carcer
authors.forename: Antonio
authors.initials: A
authors.lastname: DiPasquale
authors.forename: Arnold L
authors.initials: AL
authors.lastname: Rheingold
authors.forename: D Michael
authors.initials: DM
authors.lastname: Heinekey
mesh_terms: D001665:Binding Sites; D018360:Crystallography, X-Ray; D005663:Furans / Q000737:chemistry; D006864:Hydrogenase / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000737:chemistry*; D013055:Spectrophotometry, Infrared
chemical_list: D005663:Furans; D007506:Iron-Sulfur Proteins; D009942:Organometallic Compounds; C018674:tetrahydrofuran; D007501:Iron; C118830:iron hydrogenase; D006864:Hydrogenase