Synthesis and characterization of novel tantalum(V) complexes containing oxazoline and DMA ligation

Abstract

Two six coordinate tantalum(V) oxazoline complexes, [Ta(OX)(NMe 2) 4] ( 1) and [Ta(OX) 2(NMe 2) 3] ( 2), formed by the reaction of [Ta(NMe 2) 5] with the chelating di-nitrogen ligand 4,4-dimethyl-2-pyrrole-2-oxazoline in 1:1, 1:2 and/or 1:3 molar ratios have been investigated. The structural study of 1 and 2 by X-ray crystallography shows that they both adopt geometries best described as distorted octahedral with N–Ta–N angles of 172.6(3)° and 169.4(2)°, respectively. The nitrogen atoms of the oxazoline are bound directly to the tantalum, leading to a five-membered metallacycle in the basal plane. The N–Ta–N and Ta–N–C angles of the basal five-membered oxazoline ring are 71° and 113–117°, respectively.