Pentabenzyltantalum: Straightforward Synthesis, X-ray Structure, and Application in the Synthesis of [O2N]TaBn3-Type and [O3N]TaBn2-Type Complexes

The direct reaction between tantalum pentachloride and benzylmagnesium chloride leads to pentabenzyltantalum, previously prepared by a two-step synthesis. The X-ray structure of pentabenzyltantalum reveals a square-pyramidal geometry. Pentabenzyltantalum was found to be an efficient starting material for the preparation of amine−phenolate complexes via toluene elimination reactions. Thus, its reactions with amine bis(phenolate) and amine tris(phenolate) ligand precursors gave the tribenzyltantalum and dibenzyltantalum complexes, respectively, in quantitative yields.