Aspects of carbonyltantalum chemistry

Article abstract of DOI:10.1016/0022-328X(92)83042-G

UV irradiation of in the presence of 2- to 4-dentate phosphines, p_n, yields n>.Ion exchange chromatography on silica gel affords the hydrido complexes HTa(CO)4p₂ or HTa(CO)3p_n (n=3,4), which can be photochemically converted into HTa(CO)2p_n.The structure in solution as judged from spectroscopic data is probably an octahedron capped by the hydride.In the solid state, an X-ray diffraction study of trans- indicates the presence of a pentagonal bipyramid with H^-, Ta and the four P in the pentagonal plane. 2-methyl-2-butene is hydrotantalated , mainly in the anti-Markovnikow manner, to yield the ?-alkyl complex Me2CH-H(Me)CTa(CO)4p₂ (p₂ = Ph2PCH2CH2PEt2).The complex HTa(CO)4/3p_n react with pentafulvenes to form η⁵-(C5H4CHR2)Ta(CO)2p_n (R2 = Me2, Ph2, NMe2 + H; p_n = PhP(CH2CH2PPh2)2).The hepta-coordinated chloride complexes ClTa(CO)6-np_n have been prepared photochemically from Cl and HTa(CO)4p_n (n = 4, p_n = 2 dppe), or by reductive carbonylation of TaCl4 in the presence of p_n (n = 3, p_n = MeP(CH2CH2CH2PMe2)2).