title: Dioxotungsten 1,2-benzenedithiolate complex stabilized by NH...S hydrogen bonds.
abstract: Novel dioxo-tungsten(VI) bis(1,2-benzenedithiolate) complexes with neighboring amide groups, as models for tungsten enzymes, (NEt4)2[W(VI)O2{1,2-S(2)-3,6-(RCONH)2C6H2}2] (R = CH3, t-Bu), were designed and synthesized. The presence of the NH...S hydrogen bond was confirmed through IR spectrometry and X-ray crystallographic analysis. In the W(VI)O2 complexes, the NH...S hydrogen bond trans to the oxo ligand is stronger than that cis to oxo. On the basis of comparisons with [W(VI)O2(1,2-S2C6H4)2](2-), the NH...S hydrogen bond positively shifted the W(VI)/W(V) redox potentials and depressed the reduction by benzoin or triphenylphosphine. These results suggest that the NH...S hydrogen bond stabilizes the oxo ligand through trans influence and regulates O-atom transfer in tungsten and molybdenum enzymes.
authors.affiliation: Chemical Analysis Research Center, National Institute for Agro-Environmental Sciences, Tsukuba, Ibaraki 305-8604, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Baba
authors.forename: Taka-aki
authors.initials: TA
authors.lastname: Okamura
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Ohama
authors.forename: Norikazu
authors.initials: N
authors.lastname: Ueyama
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000737:chemistry; D001555:Benzene Derivatives / Q000138:chemical synthesis / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005560:Formate Dehydrogenases / Q000737:chemistry; D006860:Hydrogen Bonding; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013438:Sulfhydryl Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D014414:Tungsten / Q000737:chemistry*
chemical_list: D001555:Benzene Derivatives; D009942:Organometallic Compounds; D013438:Sulfhydryl Compounds; D005560:Formate Dehydrogenases; D000445:Aldehyde Oxidoreductases; D014414:Tungsten