Synthesis and X-ray Crystal Structure of [(THF)Zn(O₂(OH)SiR)]₄ (R = (2,6-<i>i</i>-Pr₂C₆H₃)N(SiMe₃)): Enroute to Larger Aggregates^†

Reaction of aminosilanetriol RSi(OH)3 (1) (R = (2,6-i-Pr2C6H3)N(SiMe3)) with diethyl zinc at room temperature in 1:1 stoichiometric ratio affords [(THF)Zn(O2(OH)SiR)]4 (2) (R = (2,6-i-Pr2C6H3)N(SiMe3)) in good yield. The single-crystal X-ray diffraction studies reveal that 2 is monoclinic, P21, with a = 17.117(3) Å, b = 16.692(5) Å, c = 17.399(4) Å, α = γ = 90°, β = 91.45(7)°, and Z = 2. The molecular structure of 2 contains two puckered eight-membered Zn2Si2O4 rings, which are connected by the Zn−O bonds and form two planar four-membered Zn2O2 rings. Compound 2 contains an unreacted hydroxyl group on each silicon atom, and hence, we carried out the reactions of 2 with dimethylzinc and methyllithium to form [Zn4(THF)4(MeZn)4(O3SiR)4] (3) (R = (2,6-i-Pr2C6H3)N(SiMe3)) and [(L)ZnLi(O3SiR)]4 (4) (L = 1,4-(Me2N)2C6H4, R = (2,6-i-Pr2C6H3)N(SiMe3)), respectively. This suggested that 2 could be an intermediate product formed during the synthesis of 3 and 4.