That methyl groups attached to carbon atoms are electron donors must not be generally assumed. In boron clusters, Me groups on boron are electron withdrawing. At the B3LYP/6-31G* level of theory, it has been proven that the Mulliken charge on each boron after substitution of -H by -Me increases by +0.18 unit. This leads to a high build-up of positive charge upon permethylation, then hampering it. Experimentally, this is proven by the synthesis of 9-I0.707H0.293-12-Cl0.566H0.434-3,4,5,6,7,8,10,11-Me8-1,2-C2B10H2, in which positions 9 and 12 were first methylated and then attacked by nucleophiles. This is substantiated by the synthesis of 3,6,8,9,10,12-Me6-1,2-C2B10H6 under the same experimental conditions but with time control.

The use of nucleophilic and electrophilic processes allow the designed synthesis of several B-iodinated derivatives of o-carborane. Because of the straightforward Pd-catalyzed conversion of B-I to B-C bond with Grignard reagents, such as methylMgBr and biPhenylMgBr, both, symmetrical 3,6-R 2-1,2- closo-C 2B 10H 10 and asymmetrical 3-I-6-Me-1,2- closo-C 2B 10H 10 could be obtained. Not only conventional reactions in solution have been studied but also a highly efficient, clean and fast solvent-free procedure has provided successful results to regioselectively produce B-iodinated o-carborane derivatives by a careful control of the reaction conditions. The high number of nonequivalent leaving groups in boron iodinated o-carborane derivatives opens the possibility through B-C coupling to materials with novel possibilities and to self-assembling due to the enhanced polarizability of the C-H bond.