Polylithiated Tetraaminosilanes:  Synthesis and Characterization of (Et2O·Li)4[Si(Nnaph)4] and X-ray Structure of {THF·Li3[Si(NiPr)3(NHiPr)]}2

The treatment of SiCl4 with 4 equiv of Li2(Nnaph) (naph = 1-naphthyl) in diethyl ether gives (Et2O·Li)4[Si(Nnaph)4] (4), which, upon reaction with excess tBuNH3Cl or MeO3SCF3, generates Si[N(H)naph]4 (5) or Si[N(Me)naph]4 (6), respectively. The centrosymmetric dimer {THF·Li3[Si(NiPr)3(NHiPr)]}2 (7), formed via trilithiation of Si[N(H)iPr]4 with n-butyllithium, consists of a bis-THF-solvated Li6(NiPr)6 cyclic ladder bicapped by two Si−N(H)iPr units. Crystal data for 7: C32H74Li6N8O2Si2, monoclinic, P21/n, a = 10.661(7) Å, b = 16.964(5) Å, c = 12.405(4) Å, β = 93.22(4)°, V = 2239.9(15) Å3, and Z = 2.