Crystal and molecular structure of trichlorobis-(NN′-di-isopropylacetamidinato)tantalum(V)

Abstract

Crystals of the title compound are monoclinic, space group P2₁/a with a= 17·420(8), b= 11·924(8), c= 11·027(8)Å, β= 95·88(8)°, Z= 4. The structure was solved by Patterson and Fourier methods from diffractometer data and refined by least-squares techniques to R 0·064 for 2003 independent reflections. The seven-co- ordinate monomer is a highly distorted pentagonal bipyramid with two chlorine atoms in axial positions [2·386(6), 2·370(6)Å], one chlorine [2·436(6)] and four nitrogens [2·098(14), 2·193(16), 2·180(20), and 2·058(16)Å] occupying the pentagonal girdle. There are many close contacts involving the isopropyl groups which cause considerable distortion to the polyhedron. The maximum deviation of a contributing atom from the least-squares plane of the TaClN₄ unit is 0·33 Å.