Syntheses, structures, and reactions of Di-mu-hydroxo dinuclear complexes of tungsten(IV) and molybdenum(IV)

The title compounds have been prepared in good yields by reaction of Cp(2)MH(2) (M = W or Mo) with Cp(2)M(OTs)(2) (OTs = P-CH3C6H4SO3) in aqueous acetone. The products were investigated by IR, H-1 NMR, and C-13 NMR spectroscopy as well as by X-ray crystallography. The molecules of the two compounds are isostructural. The structures comprise a planar four-membered ring consisting of alternating M and O atoms. In methanol solution, H-1 NMR chemical shifts for the cyclopentadienyl units of the complexes are significantly deshielded with respect to those for the parent dihydrides. The reactions between these complexes and tertiary phosphines in alcoholic solvents yield novel alkoxo complexes [Cp(2)M(PR(3))(R'O)](+)(OTs(-)) (2) (R = Et, Bu(n), and Ph; R' = Me, Et, Pr-i, CF3CH2, and Ph). The structure of the complex with (R = Bu(n) and R' = CF3CH2, determined by a single-crystal X-ray diffraction study, exhibits a distorted tetrahedral geometry with Mo-P = 2.540 Angstrom and internal angle CP1-Mo-CP2 (CP is the centroid of the cyclopentadienyl ligand) = 132.8 degrees.