PREPARATION AND PROPERTIES OF MOLYBDENUM AND TUNGSTEN DINITROGEN COMPLEXES .35. SYNTHESIS OF DIAZOALKANE AND HYDRAZIDO(2-) COMPLEXES OF TUNGSTEN CONTAINING A PI-ACCEPTOR LIGAND

Diazoalkane complexes [MCl2(NNCRR')(PMe2Ph)3] (M = W or Mo; R, R' = Me or Ph), derived from dinitrogen complexes cis-[M(N2)2(PMe2Ph)4], reacted with various pi-acceptor molecules at 50-degrees-C to give a series of new diazoalkane complexes [MCl2(L)(NNCRR')(PMe2Ph)2] (L = olefins, CO, tBuNC, or aldehydes). Analogous substitution of ethylene or CO for one phosphine ligand occurred in the hydrazido(2-) complex [WCl2(NNH2)(PMe2Ph)3], which resulted in the formation of [WCl2(L)(NNH2)(PMe2Ph)2]. Condensation of this new hydrazido(2-) complex (L = CO) with aldehyde or ketone gives the diazoalkane complexes of the type [WCl2(CO)(NNCRR')(PMe2Ph)2]. The structures of [WCl2(C2H4)(NNCMe2)(PMe2Ph)2] (4) and [WCl2(eta-2-p-CH3C6H4CHO)(NNCMePh) (PMe2Ph)2] (13) were determined by single-crystal X-ray diffraction studies: 4 crystallizes in the monoclinic space group P2(1)/n with a = 12.755(7), b = 18.528(6), c = 10.791(3) angstrom, beta = 93.25(4)-degrees, Z = 4, and R = 0.036 for 4199 reflections, while 13 crystallizes in the monoclinic space group P2(1)/n with a = 31.519(13), b = 11.360(5), c = 9.348(3) angstrom, beta = 92.28(3)-degrees, Z = 4, and R = 0.053 for 3522 reflections. Both have an octahedral geometry with the diazoalkane and the pi-acceptor ligands in mutual cis positions.