Synthesis and Characterization of Siloxy, Aminoxy, and Oxo Complexes from the Reaction of a Tantalum Amide Silyl Complex with Oxygen

(Me2N)4Ta−SiButPh2 (1) reacts with O2 to give (Me2N)4Ta(OSiButPh2) (2), (Me2N)3Ta(ONMe2)(OSiButPh2) (3), and the unusual μ-oxo amino (Me2N)2(Ph2ButSiO)2(μ,η2-Me2NCH2NMe)2Ta2(μ-O)2 (4) containing two bridging chelating (aminomethyl)amides -N(Me)CH2NMe2. The dimer 4 was characterized by X-ray crystallography. 2 also reacts with O2 to give both 3 and 4. Reaction pathways in the formation of these complexes are discussed. In reactions of O2 with d0 1 and 2, oxidation of the ligands is the prevailing pathway.