[(ZnSb6)2]4−: a new structure type for coupled norbornadiene-like subunits

Abstract

The norbornadiene-like bimetallic dimer [(ZnSb₆)₂]⁴⁻ anion (1) was prepared by direct extraction from a ternary alloy with nominal composition “K₆ZnSb₅” in ethylenediamine/toluene/2,2,2-crypt solutions. The structure represents a new type for coupled norbornadiene subunits, however, distortions around the Zn²⁺ ions degrade the overall symmetry. The Zn²⁺ ions achieve a 16e⁻ configuration and reside in near perfect ZnSb₃ triangular coordination environments. DFT calculations reveal a 2.35 eV HOMO–LUMO gap and suggest covalent bonding between the Zn and Sb atoms.