Synthesis of Silyl Aluminum Reagents: Relevance Toward Atomic Layer Deposition of Metal Silicides and the Serendipitous Synthesis of a Novel Al-Hydride Cluster

Abstract

intramolecular amine-coordinated mono-silyl aluminum complex Me 2 N-(CH 2 ) 3 ( t BuMe 2 Si) 2 SiAlCl 2 was prepared by the reaction of Me 2 N(CH 2 ) 3 ( t BuMe 2 Si) 2 SiLi with AlCl 3 in Et 2 O. In addition, reaction of [( t BuMe 2 Si) 2 AlBr] 2 with LiAlH 4 yields the novel aluminum hydride cluster [( t BuMe 2 Si) 2 Al(μ-H)AlH 3 ] 6 which upon addition of TMEDA yields the ion pair [(( t BuMe 2 Si) 2 AlH) 2 (μ-H)] − [AlH 2 (TMEDA) 2 ] + . The amine-coordinated di-and tri-silyl aluminum complexes possess higher thermal stability than the analogous etherate complexes and are reasonably volatile (100−140 °C, 0.2 Torr). The materials presented herein were analyzed via thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) to assess their viability as potential ALD precursors.