title: Selective oxidations of a dithiolate complex produce a mixed sulfonate/thiolate complex.
abstract: Oxygenation or peroxidation of a planar, tetracoordinate, low-spin nickel(II) complex of a N2S2-donor ligand, (N,N'-dimethyl-N,N'-bis(2-mecaptoethyl)-1, 3-propanediaminato)nickel(II), proceeds via the formation of a mixed sulfinate/thiolate complex and leads to the production of a novel dimeric complex containing both sulfonate and thiolate ligands. Thus, reaction proceeds via selective oxidation of the sulfinate sulfur atom, leaving the thiolate reduced. The novel sulfonate/thiolate complex has been isolated and characterized by electospray ionization mass spectrometry and single-crystal X-ray diffraction. Crystals form in the monoclinic space group P2(1)/c with cell dimensions a = 8.4647(12) A, b = 12.592(3) A, and c = 12.531(2) A, angles alpha = gamma = 90 degrees and beta = 106.645(11) degrees , and Z = 2. The structure was refined to R = 5.20% and R(w) = 12.86% [I > 2sigma(I)]. The isolation of this mixed sulfonate/thiolate complex from oxidation of a mixed sulfinate/thiolate complex provides experimental evidence for the formation of a sulfonate ligand via a Ni-O-O-SO2R intermediate, as suggested by recent density functional theory calculations.
authors.affiliation: Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA.
authors.forename: Balwant S
authors.initials: BS
authors.lastname: Chohan
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Maroney
mesh_terms: D001665:Binding Sites; D015392:Chemistry, Inorganic / Q000379:methods*; D019281:Dimerization; D006836:Hydro-Lyases / Q000737:chemistry / Q000378:metabolism; D008024:Ligands; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013451:Sulfonic Acids / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D008024:Ligands; D013438:Sulfhydryl Compounds; D013451:Sulfonic Acids; D006836:Hydro-Lyases; C048831:nitrile hydratase