title: Electron-rich diferrous-phosphane-thiolates relevant to Fe-only hydrogenase: is cyanide "nature's trimethylphosphane"?
abstract: The two-step one-pot oxidative decarbonylation of [Fe2(S2C2H4)(CO)4(PMe3)2] (1) with [FeCp2]PF6, followed by addition of phosphane ligands, led to a series of diferrous dithiolato carbonyls 2-6, containing three or four phosphane ligands. In situ measurements indicate efficient formation of 1(2+) as the initial intermediate of the oxidation of 1, even when a deficiency of the oxidant was employed. Subsequent addition of PR3 gave rise to [Fe2(S2C2H4)(mu-CO)(CO)3(PMe3)3]2+ (2) and [Fe2(S2C2H4)(mu-CO)(CO)2(PMe3)2(PR3)2]2+ (R = Me 3, OMe 4) as principal products. One terminal CO ligand in these complexes was readily substituted by MeCN, and [Fe2(S2C2H4)(mu-CO)(CO)2(PMe3)3(MeCN)]2+ (5) and [Fe2(S2C2H4)(mu-CO)(CO)(PMe3)4(MeCN)]2+ (6) were fully characterized. Relevant to the H(red) state of the active site of Fe-only hydrogenases, the unsymmetrical derivatives 5 and 6 feature a semibridging CO ligand trans to a labile coordination site.
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign, 505 S. Mathews St., Urbana, IL 61801, USA.
authors.forename: Jarl Ivar
authors.initials: JI
authors.lastname: van der Vlugt
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Rauchfuss
authors.forename: Scott R
authors.initials: SR
authors.lastname: Wilson
mesh_terms: D001665:Binding Sites; D002384:Catalysis; D018360:Crystallography, X-Ray; D003486:Cyanides / Q000737:chemistry*; D004583:Electrons; D005296:Ferrous Compounds / Q000737:chemistry*; D006864:Hydrogenase / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010720:Phosphines / Q000737:chemistry*; D011487:Protein Conformation; D013055:Spectrophotometry, Infrared; D013457:Sulfur Compounds / Q000737:chemistry*
chemical_list: D003486:Cyanides; D005296:Ferrous Compounds; D007506:Iron-Sulfur Proteins; D008024:Ligands; D010720:Phosphines; D013457:Sulfur Compounds; C118830:iron hydrogenase; D006864:Hydrogenase; C044646:phosphine