STABILIZATION OF ZERO-VALENT HYDRAZIDO COMPLEXES BY PHOSPHINE-LIGANDS - CRYSTAL-STRUCTURE OF FAC-(CO)3(DPPE)W=NNME2, A NITRENE ANALOG TO FISCHER CARBENES

The zero-valent tungsten hydrazido complex (CO)5W=NNMe2 (2) reacts with phosphines or phosphites to form cis-(CO)n(PR3)5-nW=NNMe2 (3, 8, and 10). Spectroscopic data show that these complexes contain bent hydrazido ligands, as does 2. Kinetics are consistent with substitution of CO by PR3 via a dissociative process. Complexes 3, 8, and 10 are significantly more stable than 2, with fac-(CO)3(DPPE)W=NNMe2 (10b) [DPPE = 1,2-bis(diphenylphospbino)ethane] being isolable as a crystalline solid. Complex 10b was characterized by X-ray crystallography: P2(1)/n; a = 8.4406 (20) angstrom, b = 23.9747 (57) angstrom, c = 16.5073 (41) angstrom, beta = 92.36 (2)-degrees, V = 3337.6 (25) angstrom3, Z = 4, R(F) = 6.3%, R(wF) = 7.2%, for 3025 reflections, F(o) > 3-sigma(F(o)).