title: Iron Hydride Detection and Intramolecular Hydride Transfer in a Synthetic Model of Mono-Iron Hydrogenase with a CNS Chelate.
abstract: We report the identification and reactivity of an iron hydride species in a synthetic model complex of monoiron hydrogenase. The hydride complex is derived from a phosphine-free CNS chelate that includes a Fe-C(NH)(═O) bond (carbamoyl) as a mimic of the active site iron acyl. The reaction of [((O═)C(HN)N(py)S(Me))Fe(CO)2(Br)] (1) with NaHBEt3 generates the iron hydride intermediate [((O═)C(HN)N(py)S(Me))Fe(H)(CO)2] (2; δFe-H = -5.08 ppm). Above -40 °C, the hydride species extrudes CH3S(-) via intramolecular hydride transfer, which is stoichiometrically trapped in the structurally characterized dimer μ2-(CH3S)2-[((O═)C(HN)N(Ph))Fe(CO)2]2 (3). Alternately, when activated by base ((t)BuOK), 1 undergoes desulfurization to form a cyclometalated species, [((O═)C(NH)NC(Ph))Fe(CO)2] (5); derivatization of 5 with PPh3 affords the structurally characterized species [((O═)C(NH)NC)Fe(CO)(PPh3)2] (6), indicating complex 6 as the common intermediate along each pathway of desulfurization.
authors.affiliation: Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Gummadi
authors.initials: G
authors.lastname: Durgaprasad
authors.affiliation: Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Zhu-Lin
authors.initials: ZL
authors.lastname: Xie
authors.affiliation: Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Rose
mesh_terms: D002614:Chelating Agents / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006859:Hydrogen / Q000737:chemistry*; D006864:Hydrogenase / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D066244:Proton Magnetic Resonance Spectroscopy; D013055:Spectrophotometry, Infrared
chemical_list: D002614:Chelating Agents; D007506:Iron-Sulfur Proteins; D006859:Hydrogen; D007501:Iron; C118830:iron hydrogenase; D006864:Hydrogenase