Synthesis and Structural Characterization of Highly Chlorinated, Brominated, Iodinated, and Methylated Carborane Anions, 1-H-CB9X9 -, 1-NH2-CB9X9 - (X = Cl, Br, I), and 1-H-CB9(CH3)9 -

The highly chlorinated, brominated, and iodinated carborane anions 1-R-CB9X9 - (R = H, NH2; X = Cl, Br, I) were prepared in high yields by treatment of [Me3NH][1-R-CB9H9] with excess ICl, Br2/triflic acid, and I2/triflic acid, respectively, in sealed tubes at 180−240 °C. With the aid of a Pd catalyst, B−I bonds could be converted into the B−Me bonds by treatment with excess MeMgBr, which led to the preparation of the permethylated species 1-H-CB9Me9 - in good yield. These new anions were fully characterized by 1H, 13C, and 11B NMR, IR, and negative-ion MALDI MS spectroscopy. Some were further characterized by single-crystal X-ray analyses. The weakly coordinating nature of these new anions was probed by 29Si chemical shifts.