W(CO)3(PMTA) (PMTA = MeN(CH2CH2NMe2)2) as a starting material for syntheses of W(CO)3(PR3)3, W(CO)3(η6-arene), and the protonated W(H)(CO)3(PR3)3+ complexes

Article abstract of DOI:10.1016/0022-328X(91)86100-5

A new and improved method for the synthesis of M(CO)3(PMTA) (M = W, Mo) from M(CO)6 and PMTA (MeN(CH2CH2NMe2)2) is described.The tridentate nitrogen ligand in W(CO)3(PMTA) is replaced, under relatively mild conditions, by tertiary phosphines (PMe3, PEt3, PMe2Ph, PMePh2, PhP(CH2CH2PPh2)2, CH3C(CH2PPh2)3, and Ph2P(CH2)nPPh2 where n = 1, 2) and arenes (C6H6, MeC6H5, p-Me2C6H4, C6Me6, C6H5Cl), which provides a general synthetic method for the preparation of W(CO)3(PR3)3 and W(CO)3(η⁶-arene) complexes.The reactions of W(CO)3(L)3 with CF3SO3H in CH2Cl2 solution yield the hydrido derivatives W(H)(CO)3(L)3⁺ which were characterized by their 1H and 31P NMR spectra at different temperatures.These studies show the W(H)(CO)3(L)3⁺ complexes to be fluxional as a result of both hydride and phosphine ligand migration.