Transfer of Amide and 2-Methoxyethoxy Groups and Sodium Encapsulation in the Reaction of TaCl3[N(TMS)2]2 with Sodium Bis(2-methoxyethoxy)aluminum Hydride: X-ray Structure of [NaAl{N(TMS)2}(OCH2CH2OMe)3

Abstract

The reaction between the tantalum compound TaCl3[N(TMS)2]2 and the hydridic reducing agent sodium bis(2-methoxyethoxy)aluminum hydride (Vitride) has been investigated in toluene solution at room temperature and found to afford the dimeric aluminate complex [NaAl{N(TMS)2}(OCH2CH2OMe)3]2 as the sole isolable product. The molecular structure of the product establishes the existence of a four-coordinate aluminum atom and the formal transfer of the 2-methoxyethoxy and bis(trimethylsilyl)amide groups to the aluminate product. The aggregation of two NaAl{N(TMS)2}(OCH2CH2OMe)3 units serves to bind the two sodium cations in a crown-ether fashion through six ancillary oxygen atoms. The reaction between TaCl3[N(TMS)2]2 and the reducing agent Vitride has been examined and found to furnish the dimeric aluminate complex [NaAl{N(TMS)2}(OCH2CH2OMe)3]2 in low yields. X-ray diffraction analysis confirms the attendant transfer of the 2-methoxyethoxy and bis(trimethylsilyl)amide groups to the aluminate product, which exists as a dimer that encapsulates two sodium counter ions via the 2-methoxyethoxy appendages.