Features of Cobalt(II) Complexation with Azaheteracyclic Ligands in the Presence of a Monohydroxy-Substituted Derivative of the closo-Dodecaborate Anion

Cobalt(II) complexation with azaheterocyclic ligands L (L = 2,2'-bipyridyl, 1,10-phenanthroline, and 2,2'-bipyridylamine) in the presence of a monohydroxy-substituted derivative of the closo-dodecaborate anion [B₁₂H₁₁OH]^2– has been studied. Depending on the nature of the organic ligand and the synthesis conditions, coordination compounds [Co^III(Bipy)₂Cl₂]₂[B₁₂H₁₁OH], [Co^II(Phen)₃][B₁₂H₁₁OH] and [Co^II(Bipy)₃][B₁₂H₁₁OH] with the boron cluster anion as a counterion, as well as the mixed-ligand complex [Co^II(BPA)₂Cl₂] of a known structure, have been isolated and characterized by X-ray diffraction. For the first time, a redox reaction leading to the formation of a cobalt(III) complex in air has been observed for a system containing cobalt(II) and a substituted derivative of the boron cluster anion without the introduction of additional oxidizing agents.