Reactions of LiE(SiMe(3))(3), E = Si, Ge: X-ray Crystal Structure of the Cyclotetrastannane [ClSnSi(SiMe(3))(3)](4).

Reaction of SnCl(2).dioxane with 2 equiv of Li(THF)(3)Si(SiMe(3))(3) in hexane afforded the cyclotetrastannane [(Me(3)Si)(3)SiSnCl](4) in reasonable yield. From pentane, the product crystallized as a red-orange disolvate in the P&onemacr; space group (triclinic) with a = 14.735(2) Å, b = 14.976(2) Å, c = 24.066(3) Å, alpha = 76.94 degrees, beta = 76.19 degrees, gamma = 62.11 degrees, V = 4517.5 Å(3), and Z = 2. The Sn(4) ring consisted of a slightly distorted, nonplanar (fold angle = 18.9 degrees ) rectangle with Sn-Sn distances of 2.8054(6), 2.8111(6), 2.9122(6), and 2.9146(6) Å. The pentane molecules were disordered. Selected mono- and dihalogermanes were treated with 1 equiv of Li(THF)(3)Si(SiMe(3))(3) or Li(THF)(2.5)Ge(SiMe(3))(3), affording (Me(3)Si)(3)EGe(CF(3))(3) (E = Si, Ge) and (Me(3)Si)(3)GeGeR(3) (R = Cl, CH(3), C(6)H(5)). Besides the monosubstitution product, the reaction of GeCl(4) with 1 equiv of Li(THF)(2.5)Ge(SiMe(3))(3) also gave a small amount of the linear tetragermane (Me(3)Si)(3)GeGeCl(2)GeCl(2)Ge(SiMe(3))(3). Good yields of the analogous phenyl derivative, (Me(3)Si)(3)GeGePh(2)GePh(2)Ge(SiMe(3))(3), were obtained by treating Ph(2)GeCl(2) with 2 equiv of the lithium-germyl reagent.