COORDINATION OF HEAVIER ALKALI-METALS BY POLYIMIDO ANTIMONY(III) LIGANDS - SYNTHESES AND STRUCTURES OF [(SB-2(NC6H11)(4))(2)M-4] (M = LI ORNA), LI[((ME2N)SB(MU-NC6H11)(2))(2)SB] AND M[((C6H11NH)SB(MU-NC6H11)(2))(2)SB]CENTER-DOT-2THF (M = K OR RB)

The in situ reactions of MCH2Ph (M = Na, K or Rb) with C6H11NH2 in tol uene followed by the addition of the appropriate stoichiometric quanti ty of Sb(NMe2)(3) gave the new heterobimetallic antimony(III)/alkali m etal complexes [{Sb-2(NC6H11)(4)}(2)Na-4] and M[{(C6H11NH)Sb(mu-NC6H11 )(2)}(2)Sb]. 2thf (M = K or Rb). Comparison of the crystal structures of these species with those of the lithium complexes [{Sb-2(NC6H11)(4) }(2)Li-4] and Li[{(C6H11NH)-Sb(mu-NC6H11)(2)}(2)Sb} reveals that the g eometries of these heterobimetallic cages are fundamentally dictated b y the rigidity of the [Sb-2(NC6H11)(4)](2-) and [{(C6H11NH)Sb(mu-NC6H1 1}(2)Sb](-) anions.