title: Substrate and metal control of barrier heights for oxo transfer to Mo and W bis-dithiolene sites.
abstract: Reaction coordinates for oxo transfer from the substrates Me(3)NO, Me(2)SO, and Me(3)PO to the biologically relevant Mo(IV) bis-dithiolene complex [Mo(OMe)(mdt)(2)](-) where mdt = 1,2-dimethyl-ethene-1,2-dithiolate(2-), and from Me(2)SO to the analogous W(IV) complex, have been calculated using density functional theory. In each case, the reaction first proceeds through a transition state (TS1) to an intermediate with substrate weakly bound, followed by a second transition state (TS2) around which breaking of the substrate X-O bond begins. By analyzing the energetic contributions to each barrier, it is shown that the nature of the substrate and metal determines which transition state controls the rate-determining step of the reaction.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, California 94305, USA.
authors.forename: Adam L
authors.initials: AL
authors.lastname: Tenderholt
authors.forename: Keith O
authors.initials: KO
authors.lastname: Hodgson
authors.forename: Britt
authors.initials: B
authors.lastname: Hedman
authors.forename: Richard H
authors.initials: RH
authors.lastname: Holm
authors.forename: Edward I
authors.initials: EI
authors.lastname: Solomon
mesh_terms: D008982:Molybdenum / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D014414:Tungsten / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy
chemical_list: D013438:Sulfhydryl Compounds; D008982:Molybdenum; D014414:Tungsten