HALF-SANDWICH HYDRAZIDO(2-) COMPLEXES OF NIOBIUM

The compounds [Nb(eta-C5H4R)Cl-2(NNMeR')] (R = H or Me, R' = Me or Ph) , [Nb(eta-C5H4R)(OBut)(2)(NNMe2)] (R = H or Me), [Nb(eta-C5H4Me) Br(OB ut)(NNMe2)], [Nb(eta-C5H5)(NMe2),(NNMe2)], [Nb(eta-C5H4R)(CH2CMe2Ph)(2 )(NNMe2)] (R = H or Me), [Nb(eta-C5H5)(CH2SiMe3)(2)(NNMe2)], cis-[Nb(e ta-C5H5)Cl-2(NNMe2)], cis-[Nb(eta-C5H4R)Cl-2(NNMe2)(PMe3)] (R = H or M e), trans-[Nb(eta-C5H4R)Cl(NNMe2)(PMe3)(2)]Cl (R = H or Me) and trans- [Nb(eta-C5H5)Cl(NNMe2)(PMe3)(2)][PF6] have been prepared and character ised. A structure determination of [Nb(eta-C5H5)Cl-2(NNMe2)] showed it to be a dimer with one hydrazide ligand acting as monodentate to one metal centre and a second hydrazide bridging both metal centres in a m u-eta(2) fashion. The structure of [Nb(eta-C5H5)Cl-2(NNMe2){P(OMe)(3)} ] shows a cis disposition of the hydrazide and phosphite ligands.