Methylation and Demethylation in Cobaltabis(dicarbollide) Derivatives

B(8)−R and B(8‘)−R (R = alkyl) disubstituted derivatives of the cobaltabis(dicarbollide) anion [3,3‘-Co(C2B9H11)2]- are reported. The synthesis was achieved by application of a modified Kumada reaction to produce B−C bonds. Molecules containing B(8)−C and B−O bonds are also generated, and interestingly, a high-yield intramolecular oxodemethylation is observed for the first time in boron cluster chemistry. It is also shown that the 11B NMR spectrum of Cs[3,3‘-Co(C2B9H11)2] derivatives is the result of the addition of the individual halves.