Synthesis of the novel ionic liquid [N-pentylpyridinium]+ [closo-CB11H12]− and its usage as a reaction medium in catalytic dehalogenation of aromatic halides

The novel, low‐melting‐point (19 °C) salt [N‐pentylpyridinium]+ [closo‐CB11H12]− (2) was synthesized in 93% yield and characterized by elemental analysis, IR spectroscopy, and 1H, 13C, and 11B NMR spectroscopy. The salt was used as a solvent in several dehalogenation reactions of mono‐ and poly‐chlorides and ‐bromides, catalyzed by the palladium complexes PdCl2(PPh3)2, PdCl2(dppe), and PdCl2(dppf). Complete debromination of C6Br6, 1,2,4,5‐tetrabromobenzene, C60Br8, and C60Br24 was accomplished quite rapidly, whereas dechlorination of 1,2,4‐trichlorobenzene proceeded more slowly, but with excellent products selectivity. Copyright © 2003 John Wiley & Sons, Ltd.