Synthesis and structure of halogen derivatives of 9-trimethylammonio-7,8-dicarba-nido-undecaborane [9-Me3N-7,8-C2B9H11]

Halogenation of the charge-compensated nido-carborane [9-Me3N-7,8-C2B9H11] (1) with elemental halogens X2 (X = Cl, Br, I) was investigated. Derivatives of 1 with substitution degree varying from one to three were synthesized and characterized by 1H and 11B NMR. In all compounds positions of substitution were determined by 11B–11B COSY NMR. Structures of [11-I-9-Me3N-7,8-C2B9H10], [6,11-Br2-9-Me3N-7,8-C2B9H9] and [1,6,11-Br3-9-Me3N-7,8-C2B9H8] were established using single crystal X-ray diffraction.