BROMODICYCLOPENTADIENYLNIOBIUM COMPLEXES

Article abstract of DOI:10.1016/S0022-328X(00)99255-6

The reaction of NbX5 (X = Cl, Br) with an excess of NaCp (Cp = C5H5) followed by the addition of HBr gives (η⁵-C5H5)2NbBr2 (I) in low yield.The reduction of I with Na/Hg or NaNaph in a molar ratio 1/1 gives (η⁵-C5H5)2NbBr (II), whereas the same reaction in the presence of ?-acid ligands gives (η⁵-C5H5)2NbBrL (III, L = CO; IV, L = PMe2Ph; V, L = P(OMe)3; VI, L = PhC<*>CPh; VIII, L = PhC<*>CH).Finally, the reduction of I with Na/Hg in a molar ratio 2/1 gives the dimer (η⁵-C5H5)4Nb2Br3 (VIII), which contains both niobium(III) and niobium(IV).The chemical and structural characteristics of all these compounds are described.