Iminosilanes as Precursors for Monomeric Bis(silyl)aminomethylalanes and Silyliumtrichloroaluminates – Synthesis and Crystal Structures

Abstract

The iminosilanes (Me₃C)₂Si=NR [R=Si(CMe₃)₂C₆H₅,Si(CHMe₂)CMe₃] react with AlMe₃ to give the monomeric aminodimethylalanes Me₂Al—N(R)Si(CMe₃)₂Me 1 [R : Si(CMe₃)₂ C₆H₅] and 2 [R : Si(CHMe₂)₂CMe₃]. The reaction of (Me₃C)₂Si=N—Si(CMe₃)₂ C₆H₅ and Me₂AlCl affords the monomeric aminochloromethylalane ClMeAl—N(R)Si(CMe₃)₂Me 3 [R : Si(CMe₃)₂C₆H₅]. The aminofluorosilanes 4 and 7 react with ⁿBuLi in thf under formation of the four-membered lithium ring derivatives (Me₃C)₂SiFN (Li (thf)₂)R 5 [R : Si(CHMe₂)₂Me] and 8 [R : Si(CHMe₃)₂H]. (Me₃C)₂SiFN (AIMe₂)R 6 [R : Si (CHMe₂)₂ Me] is obtained in reaction of the lithium derivative of 4 and Me₂AlCl in n-hexane. 8 and A1C1₃ form the silyliumtrichloroaluminate (Me₃C)₂Si=NR·AlC1₃ 9 [R : Si(CMe₃)₂H], a four-membered ring with a bridging chlorine atom. The crystal structures of 1, 3, 8 and 9 have been determined. 1 crystallizes in the space groups P2₁/n, a = 1119.3(1), b = 1560.1(2), c = 1662.2(3) pm, β = 105.75(1)°, V = 2.7936(7) nm³ , ρ_calcd = 1.065Mg/m³, Z = 4 and 3392 independent reflections, Rl(I> 2σ(I)) = 0.035, wR2 (all data) = 0.089, 3 in the space group P2₁/n, a = 1115.6(1), b = 1543.8(2), c = 1669.5(2) pm, β = 105.90(1)°, V= 2.7653(5) nm³ , ρ_calcd = 1.108 Mg/m³, Z = 4 and 4908 independent reflections, R1 (I > 2σ(I)) = 0.032, wR2 (all data) = 0.088, 8 in the space group P2₁/n, a = 931.2(1), b = 1668.1(2), c = 1950.5(3) pm, β = 97.86(1)^°, V= 3.0013(7) nm³, ρ_calcd= 1.040Mg/m³, Z =4 and 3914 independent reflections, Rl(I > 2σ (I)) = 0.044, wR2 (all data) = 0.122, and 9 in the space group P2₁/c, a = 1345.1(2), b = 1001.5(2), c = 1855.1(3) pm, β = 108.61(2)^°, V= 2.3684(7) nm³, ρ_calcd = 1.214 Mg/m³, Z = 4 and 3080 independent reflections, R1 (I > 2 σ (I)) = 0.052, wR2(all data) = 0.117.