Syntheses and crystal structures of two tin(IV) complexes with aminosilane bearing ligand

Aminosilane bearing bulky substituents on nitrogen: LH₂ (L = Me₂Si(NDipp-)₂, Dipp = 2,6-diisopropylphenyl) was reacted with BuLi in toluene. The resulting bulky chelating dianion Me ₂Si(NDipp-)₂ was used to synthesize the unusual spirocyclic heterotriatomic complex [Me₂Si(NDipp)₂] ₂Sn (1) by its reaction with SnCl₄ and the bulky heterotriatomic complex Me₂Si(NDipp)₂SnPh₂ (2) with Ph₂SnCl₂. 1 belongs to the monoclinic system, space group P2₁/n with a = 13.193(2), b = 20.663(3), c = 20.403(3) A, β = 99.954(2)°, V = 5478.3(15) A³, C₅₅H _85.5N₄Si₂Sn, M_r = 977.64, Z = 4, D_c = 1.185 Mg/m³, μ(MoKα) = 0.547 mm ^-1, F(000) = 2086, S = 1.000, the final R = 0.0614 and wR = 0.1322 for 14446 observed reflections (I > 2σ(I)) and R = 0.0797 and wR = 0.1456 for all data. 2 belongs to the triclinic system, space group P1 with a = 10.36(15), b = 13.204(7), c = 14.363(7) A, α = 90.214(10), β = 106.182(7), γ = 109.854(8)°, V = 1764.4(15) A³, C ₃₈H₅₀N₂SiSn, M_r = 681.58, Z = 2, D_c = 1.283 Mg/m³, μ(MoKα) = 0.785 mm ^-1, F(000) = 712, S = 1.002, the final R = 0.0498 and wR = 0.0955 for 7533 observed reflections (I > 2σ(I)) and R = 0.0676 and wR = 0.1018 for all data. In the structure of 1, the tin atom is located in the spirocyclic center of the two fused four-membered SnN₂Si rings. The two complexes were characterized by ¹H NMR, elemental analysis, and single-crystal X-ray structural analysis.