Synthesis, characterization, and biomimetic chemistry of cis-oxosulfidomolybdenum(VI) complexes stabilized by an intramolecular Mo(O)=S...S interaction.

The reactions of jade-green Tp*MoIVO(S2PR2) [Tp* = hydrotris(3,5-dimethylpyrazol-1-yl)borate; R = Et, Pri, Ph] with propylene sulfide produce ochre-red Tp*MoVIOS{SP(S)R2}. The complexes have been characterized by microanalysis, mass spectrometry, cyclic voltammetry, spectroscopy (IR, NMR, UV-vis, and X-ray absorption), and X-ray crystallography. The distorted-octahedral isopropyl and phenyl derivatives feature a tridentate fac-Tp* ligand, a terminal oxo ligand, and a unique five-membered Mo(=S){SP(=S)R2 ring moiety formed by a weak, intramolecular, bonding interaction between the Mo=S1 and (uncoordinated) S3=P moieties.

Oxygen Atom Transfer, Coupled Electron-Proton Transfer, and Correlated Electron-Nucleophile Transfer Reactions of Oxomolybdenum(IV) and Dioxomolybdenum(VI) Complexes.

The oxo-Mo(IV) complexes LMoO(S(2)PR(2)-S,S') [L = hydrotris(3,5-dimethylpyrazol-1-yl)borate; R = Me, Et, Pr(i)(), Ph] were prepared by reacting MoO(S(2)PR(2))(2) and KL in refluxing toluene. The dioxo-Mo(VI) complexes cis-LMoO(2)(S(2)PR(2)-S) (R = Pr(i)(), Ph) were prepared by oxidation of the oxo-Mo(IV) complexes or by reaction of LMoO(2)Cl with NaS(2)PR(2). Oxygen atom transfers from Me(2)SO to LMoO(S(2)PR(2)) were first-order with respect to Me(2)SO and complex; the overall second-order rate constants at 40 degrees C range from 9.