The BI activation in o-carborane clusters: their fate towards BH. Easy synthesis of [7,10-C2B10H13]−

The reaction of 3-I-o-carborane with Cu, Cu/PPh3, [Ni(PPh3)3], or [Pd(PPh3)4] has been studied to find the suitability of B–iodine substituted carboranes as sources of new boron-derivatives. In all these reactions a hydrodehalogenation reaction to yield o-carborane has been produced, indicating that BI activation takes place. It may be considered that BI adds oxidatively to M, but alternative explanations can be given. Reaction of 3-I-o-carborane with Na/naphthalene also produced o-carborane showing that albeit an oxidative addition is impossible for sodium the same hydrodehalogenation had taken place. The same result was also formed with Mg. Addition of 1,2-dibromoethane to the Mg/o-carborane reaction yielded [7,10-C2B10H13]−. Then, the sequence 3-I-o-carborane→o-carborane→[7,10-C2B10H13]− can be generated with only reducing agents. The synthetic procedure for [7,10-C2B10H13]− is very simple and produces a 97% yield of [NMe4][7,10-C2B10H13]. Basically, 1,2-C2B10H12 and Mg in excess are refluxed in THF in the presence of I2 and 1,2-dibromoethane.