Half-sandwich isocyanide, phosphine, methyl and phosphanido pentamethylcyclopentadienylniobium(V) complexes

Article abstract of DOI:10.1016/0022-328X(94)05289-N

*Cl4> (Cp^* = η⁵-C5Me5) reacts with one molar equivalent of isocyanides and phosphines to give pseudo-octahedral adducts *Cl4*L>, (L = 2,4,6-Me3C6H2NC, 1; PMe3, 2; PMe2Ph, 3; PMePh2, 4) and the dinuclear complex <*Cl4>2(μ-dmpe)>, 5.Reactions of *Cl4> with appropriate amounts of MgClMe yield the corresponding dimethyl *Cl2Me2>, 6, and tetramethyl *Me4>, 7 derivatives.Similarly, when <*Cl3>2(μ-O)> and 3 are treated with the alkylating magnesium reagent, <*Me3>2(μ-O)>, 8, and *Cl3Me(PMe2Ph)>, 9, are obtained in high yields.A new phosphanido-niobium(V) complex *Cl3(PPh2)> 10, is formed in the reaction of the starting tetrachloro complex with one equivalent of LiPPh2.All the complexes were characterized by IR and NMR spectroscopy, and most of them were studied by mass spectrometry.Keywords: Niobium; Pentamethylcyclopentadienyl; Isocyanide; Phosphine; Phosphanido; Half-sandwich cpds