Synthesis
The preparation of m-carborane was as follows: To a 500 ml three-necked flask equipped with a mechanical stirrer, nitrogen inlet, and thermometer, 10 g of a carborane-siloxane polymer (trademarked Dexsil 202) and 100 ml of tetrahydrofuran were added, along with a potassium fluoride solution (1 g KF2HO dissolved in 50 ml of water). While stirring and cooling in an ice-water bath, one drop of a methyltrialkylammonium chloride surfactant (trademarked Adogen 464) was added. The cooling bath was removed, and the two-phase reaction mixture was stirred at ambient temperature for 16 hours. The reaction mixture was transferred to a separatory funnel, and the layers were separated. The organic layer was washed with a saturated sodium chloride solution (100 ml), dried (with MgSO), and filtered. The solvent was evaporated, yielding a viscous residue. Vacuum sublimation produced 2.79 g (93% of the theoretical value) of m-carborane, which was analyzed by NMR and IR spectroscopy and by HPLC retention time compared to a real sample.
