Co-ordination of heavier alkali metals by polyimido antimony(III) ligands; syntheses and structures of [{Sb2(NC6H11)4}2M4] (M = Li or Na), Li[{(Me2N)Sb(μ-NC6H11)2}2Sb] and M[{(C6H11NH)Sb(μ-NC6H11)2}2Sb]·2thf (M = K or Rb)

Abstract

The in situ reactions of MCH2Ph (M = Na, K or Rb) with C6H11NH2 in toluene followed by the addition of the appropriate stoichiometric quantity of Sb(NMe2)3 gave the new heterobimetallic antimony(III)/alkali metal complexes [{Sb2(NC6H11)4}2Na4] and M[{(C6H11NH)Sb(µ-NC6H11)2}2Sb]·2thf (M = K or Rb). Comparison of the crystal structures of these species with those of the lithium complexes [{Sb2(NC6H11)4}2Li4] and Li[{(C6H11NH)Sb(µ-NC6H11)2}2Sb] reveals that the geometries of these heterobimetallic cages are fundamentally dictated by the rigidity of the [Sb2(NC6H11)4]2– and [{(C6H11NH)Sb(µ-NC6H11)2}2Sb]– anions.