Reactions of cyclo-(t-Bu4Sb4) with alkali metals; syntheses and crystal structures of [M(L)n(t-Bu4Sb3)] (M=Na, K; n=1, 2) and [K(L)(t-Bu3Sb2)] (L=(Me2NCH2CH2)2NMe)

Reduction of cyclo-(t-Bu4Sb4) (1) with sodium or potassium in boiling tetrahydrofuran leads to the anions [t-Bu4Sb3]− and [t-Bu3Sb2]−. Crystallization with pentamethyldiethylenetriamine (L) gives [M(L)n(t-Bu4Sb3)] (n=1, M=Na (2), K (3); n=2, M=K (4)) and [K(L)(t-Bu3Sb2)] (5). Crystal structure analyses reveal coordination of the anionic antimony ligands on the alkali metal ions for 2, 3, and 5. In contrast, no SbK interactions were observed in the structure of 4.