Synthesis, reactivity, and x-ray structure of fac-(acetonitrile)tricarbonyl[bis(diphenylphosphino)methane]tungsten. Stereoselective preparation of fac-W(CO)3(13CO)(dppm) and subsequent intramolecular rearrangement processes
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The reaction of fac-W(CO)3(CH3CN)3with an equimolar quantity of bis(diphenylphosphino)methane (dppm) results in the quantitative formation of fac-W(CO)3(dppm)(CH3CN). The solid-state structure of fac-W(CO)3(dppm)(CH3CN) was established by X-ray diffraction [P21/c (monoclinic), a = 10.937 (2) A, b = 18.399 (4) A, c = 15.194 (3) A, β = 108.33 (1)°, Z = 4]. This compound reacts with13CO to afford stereoselective fac-W(CO)3(13CO)(dppm). The reaction proceeds by a dissociative pathway, with activation parameters for loss of CH3CN being ΔH* = 23.5 kcal/mol and AS* = -6.0 eu. In a subsequent, intramolecular ligand rearrangement facial = meridional isomerization occurs. Reaction of fac- W(CO)3(dppm)(CH3CN) with an additional 1 mol of dppm leads initially to formation of fac-W(CO)3(dppm)2, which contains both bidentate and monodentate dppm ligands. Isomerization and oxidation of the unattached phosphine eventually provided mer-W(CO)3(dppm)(Ph2PCH2P(0)Ph2). The structure of the latter species was determined by X-ray diffraction [ P41(tetragonal), a = 11.186 (4) A, c = 40.498 (9) A, Z = 4]. © 1987, American Chemical Society. All rights reserved.
author list (cited authors)
Darensbourg, D. J., Zalewski, D. J., Plepys, C., & Campana, C.