Decaborane anions and the synthesis of polyhedral borane complexes of mercury(II) and cobalt(II)

Abstract

The stoicheiometric solvates NaB₁₀H₁₃,2·5dioxan and Na₂B₁₀H₁₂,2thf, and the unsolvated salt (Me₄N)₂B₁₀H₁₂ have been isolated and characterized. The synthetic use of the [B₁₀H₁₃]^– ion depends critically on both the cocation and the solvent. Me₄NB₁₀H₁₃ reacts with HgCl₂ in tetrahydrofuran (thf) to give (Me₃N)₂[Hg(B₁₀H₁₂)₂] and with py₂CoX₂ in thf to give the novel complexes Me₄N[py CoX₂B₁₀H₁₁ py] where X = Cl or Br. The [Et₃NH]⁺ salts of these cobalt complexes have also been prepared and characterized by spectroscopic, magnetic, and conductimetric techniques. The cobalt(II) atom is considered to occupy one boron position in the pentagonal face of a B₁₁ cage and is essentially five-co-ordinate with respect to bonding if the [B₁₀H₁₁py]^– moiety is considered as a bidentate ligand analogous to [B₁₀H₁₂]^2–.