Synthesis of cobalt and nickel 6,6′-diphenylbis(dicarbollides)

6,6′-Diphenyl derivatives of cobalt and nickel bis(dicarbollide) were synthesized starting from nido-carborane by the insertion—deboronation—insertion sequence of reactions. The by-products of the insertion of PhBCl₂ into the nido-carborane cage, diethyloxonium derivatives of nido-carborane [9-Et₂O-7,8-C₂B₉H₁₁] and [10-Et₂O-7,8-C₂B₉H₁₁], were isolated and characterized. Treatment of the latter with pyridine resulted in the elimination of one ethyl group to give the corresponding ethoxy derivatives. The structures of nido-carborane 10-diethyloxonium derivative and cobalt bis(dicarbollide) 6,6′-diphenyl derivative were established by X-ray diffraction analysis.