Trimethyltantalum(V) chelate complexes

Abstract

The interaction of dichlorotrimethyltantalum(V), Me₃TaCl₂, with sodium, potassium, or silver salts of various anions such as acetylacetonate or perchlorate that can act as bidentate or bridging ligands gave seven-co-ordinate, reasonably thermally stable, complexes of stoicheiometry Me₃Ta(L)₂.

The five-co-ordinate dimethylalkylamide, Me₃Ta(NMe₂)₂, has been prepared and shown to react with carbon disulphide which inserts only into the tantalum–nitrogen bond. The product, Me₃Ta(S₂CNMe₂)₂ was made independently by use of sodium dimethyldithiocarbamate. Interaction of carbon disulphide with Me₃TaCl₂ gives the eight-co-ordinate thiocarbonate (MeCS₂)₃TaCl₂.

Infrared and n.m.r. spectra are recorded; the species all appear to be non-rigid.