76771-66-9Relevant academic research and scientific papers
Synthesis, structures, and oxo transfer reactivity of bis(dithiolene)tungsten(IV,VI) complexes related to the active sites of tungstoenzymes
Lorber, Christian,Donahue, James P.,Goddard, Christine A.,Nordlander, Ebbe,Holm
, p. 8102 - 8112 (1998)
A series of bis(dithiolene)tungsten(IV,VI) complexes derived from benzene-1,2-dithiolate (bdt) has been prepared as an synthetic approach to pterin dithiolene-bound active sites of tungstoenzymes, one example of which, a archaeal oxidoreductase, has been established crystallographically (Chan et al. Science 1995, 267, 1463). With [W(IV)O(bdt)2]2- (2) as the starting compound, silylation with RR'2SiCl afforded [W(IV)(bdt)2(OSiRR'2)]1- (4). Oxidation of 4 with Me3NO gave [W(VI)O(bdt)2(OSiRR'2)]1- (5), also accessible by silylation of [W(VI)O2(bdt)2]2- (3). Reaction of 3 or 5 with Me3SiCl resulted in [W(VI)O(bdt)2Cl]1- (6), from which the unstable species [W(VI)O(bdt)2L]1- (L = Bu(t)O-, PhS-) were generated in solution. Reductive oxo transfer of 6 with L' = P(OEt)3 or Bu(t)NC/P(OEt)3 gave [W(IV)(bdt)2L'2] (8 and 9). Sulfido complex [W(VI)S(bdt)2(OSiRR'2)]1- (12) was obtained in the reaction systems 4/(PhCH2S)2S and 5/(Me3Si)2S. Structures of [WO(SPh)4]1- and [W(bdt)3]2- and eight complexes of types 4-6, 8, 9, and 12 were determined by X-ray crystallography. Complexes 4 and 5 are tungsten analogues of the desoxo Mo(IV) and monooxo Mo(VI) states of Rhodobacter sphaeroides DMSO reductase. Six types of reactivity, including oxygen atom transfer, are recognized by the synthesis and interconversion of the set of complexes. The potential biological relevance of these complexes to the structure and function of active sites in two families of tungstoenzymes is considered (RR'2 = Me3 (4); Bu(t)Me2 (4 and 5), Bu(t)Ph2 (4, 5, and 12)).
Electronic Properties of Thiolate Compounds of Oxomolybdenum(V) and Their Tungsten and Selenium Analogues. Effects of 17O, 98Mo, and 95Mo Isotope Substution upon ESR Spectra
Hanson, Graeme R.,Brunette, Andrew A.,McDonell, Angus C.,Murray, Keith S.,Wedd, Anthony G.
, p. 1953 - 1959 (2007/10/02)
The series of crystalline, mononuclear B+- and triply bridged binuclear B+- (M = Mo, W; X = S, Se; R = aryl; B = quaternary cation) salts have been isolated and the anions - (R = Et, CH2Ph) stabilized in solution at -60 deg C.The mononuclear anions are intensely colored due to a ligand-to-metal charge-transfer transition which is absent in the binuclear species.The magnetic susceptibilities of (Et4N) show a Curie dependence in the range 300-4.2 K with minor deviations in the tungsten compound.The behavior is essentially that of magnetically dilute 4d1 and 5d1 systems exhibiting a tetragonal ligand field and greatly reduced spin-orbit coupling on the metal.The presence of strong spin-spin coupling in the binuclear compounds leads to magnetic moments close to 0.ESR spectra (at X- and Q-band frequencies) of the mononuclear anions exhibit axial symmetry, and 98Mo and 95Mo isotope substitution and computer simulation permit accurate extraction of the g and hyperfine tensor anisotropies.Exceptionally narrow line widths permit observation of 17O-superhyperfine coupling in 17O-enriched - (a = 22.2*10-4 cm-1).
