Oxidation of germa- and stanna-closo-dodecaborate

Abstract

The oxidation of closo-heteroborates [GeB₁₁H₁₁]²⁻ and [SnB₁₁H₁₁]²⁻ is presented. Upon oxidation germa-closo-dodecaborate yields a symmetrical dimer exhibiting a Ge–Ge bond between two clusters. This dimer shows sulphur insertion into the Ge–Ge bond at room temperature. In contrast, oxidation of the homologous tin cluster results in an unsymmetrical dimer bearing an Sn–B bond between two clusters. The Sn–B dimer is also the product of the hydride abstraction reaction. In the presence of the donor ligand 2,2′-bipyridine, the oxidation of closo-cluster [SnB₁₁H₁₁]²⁻ leads to the Sn(IV)-half sandwich coordination compound [bipy-SnB₁₁H₁₁] which dissolves in DMSO to give the Sn(IV)-adduct [bipy(DMSO)-SnB₁₁H₁₁].