The novel mono-silyl [(R3Si)AlX2]2, di-silyl [(R3Si)2AlX]2, tri-silyl (R3Si)3Al·Et2O, and -ate-complex [(R3Si)4Al]-·Li+(Et2O)2 have been synthesized by reaction of AlX3 (X = Cl, Br) with silyl lithium reagents (tBuMe2SiLi, Et3SiLi) in Et2O.… Click to show full abstract
The novel mono-silyl [(R3Si)AlX2]2, di-silyl [(R3Si)2AlX]2, tri-silyl (R3Si)3Al·Et2O, and -ate-complex [(R3Si)4Al]-·Li+(Et2O)2 have been synthesized by reaction of AlX3 (X = Cl, Br) with silyl lithium reagents (tBuMe2SiLi, Et3SiLi) in Et2O. Treatment of these compounds with Me3N yields the corresponding amine-coordinated silyl aluminum complexes (R3Si)AlX2·NMe3, (R3Si)2AlX·NMe3, and (R3Si)3Al·NMe3. An intramolecular amine-coordinated mono-silyl aluminum complex Me2N(CH2)3(tBuMe2Si)2SiAlCl2 was prepared by the reaction of Me2N(CH2)3(tBuMe2Si)2SiLi with AlCl3 in Et2O. In addition, reaction of [(tBuMe2Si)2AlBr]2 with LiAlH4 yields the novel aluminum hydride cluster [(tBuMe2Si)2Al(μ-H)AlH3]6 which upon addition of TMEDA yields the ion pair [((tBuMe2Si)2AlH)2(μ-H)]-[AlH2(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.
               
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