Synthesis and Characterization of Iodinated Carborane

8,9,12-I₃-ortho-C₂B₁₀H₉ was isolated as a by-product from the di-iodination reaction of ortho-carborane under standard conditions [51 (link)]. Iodine (3.553 g, 14.00 mmol) and anhydrous AlCl₃ (0.400 g) were added to a solution of ortho-carborane (1.009 g, 7.00 mmol) in dichloromethane (30 mL) and heated under reflux for 8 h. Then, the reaction mixture was cooled and treated with a solution of Na₂S₂O₃·5H₂O (3.000 g) in water (50 mL). The organic phase was separated, and the aqueous fraction was extracted with dichloromethane (3 × 50 mL). The organic phases were combined, dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The crude product was purified by column chromatography on silica using diethyl ether as eluent to yield 1.900 g (69%) of 9,12-I₂-1,2-C₂B₁₀H₁₀ and 0.102 g (3%) of 8,9,12-I₃-1,2-C₂B₁₀H₉ as white powders.
8,9,12-I₃-1,2-C₂B₁₀H₉: ¹H NMR (CDCl₃, ppm): 4.13 (2H, br s, CH_carb), 3.8−2.0 (7H, br m, BH). ¹¹B NMR (CDCl₃, ppm): δ −6.1 (1B, d, J = 157 Hz), −11.5 (4B, s + d), −13.1 (2B, d, J = 171 Hz), −14.7 (1B, d, J = 220 Hz), −16.4 (1B, d, J = 220 Hz), and −17.2 (1B, s, B(8)).