Seven-coordinated tantalum trichloride complex containing substituted pyrrolyl ligand: synthesis and characterization of [N(C)4(H)3(C(H)2N(Me)2)-2]2Ta(Cl)3

bis[2-(Dimethylaminomethyl)pyrrolyl]tantalum chloride (1) was prepared by treatment of the TaCl5 with 2 equiv. of [2(dimethylaminomethyl)pyrrolyl]lithium. The solid state structure of 1 shows the seven-coordinated tantalum atom, with a geometry corresponding to a pentagonal bipyramidal structure, in which two chlorine atoms occupy the axial position with the angle of 174.8(2)°. Furthermore, variable-temperature 1H NMR spectra infer the fluxionality of the two chelating pyrrolyl ligands with an estimated energy barrier of 13.8 kcal mol-1. Compound 1 shows no catalytic activity toward ethylene polymerization even activated with MAO.