Polylithiated tetraaminosilanes: Synthesis and characterization of (Et2O center dot Li)(4)[Si(Nnaph)(4)] and X-ray structure of {THF center dot Li-3[Si(N(i)Pr)(3)(NH(i)Pr)]}(2)

The treatment of SiCl4 with 4 equiv of Li-2(Nnaph) (naph = 1-naphthyl) in d iethyl ether gives (Et2O . Li)(4)[Si(Nnaph)(4)] (4), which, upon reaction w ith excess (BuNH3Cl)-Bu-t or MeO3SCF3, generates Si[N(H)naph](4) (5) or Si[ N(Me)naph](4) (6), respectively. The centrosymmetric dimer {THF . Li-3[Si(( NPr)-Pr-i)(3)((NHPr)-Pr-i)]}(2) (7), formed via trilithiation of Si[N(H)Pr- i](4) with n-butyllithium, consists of a bis-THF-solvated Li-6(NiPT)(6) cyc lic ladder bicapped by two Si-N(H)Pr-i units. Crystal data for 7: C32H74Li6 N8O2Si2, monoclinic, P2(1)/n, a = 10.661(7) Angstrom, b = 16.964(5) Angstro m, c = 12.305(4) Angstrom, beta = 93.22(4)degrees, V = 2239.9(15) Angstrom( 3), and Z = 2.