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 (19degreesC) salt [N-pentylpyridinium](+) [closo-CB11H12](-) (2) was synthesized in 93% yield and characterized by elemental analysis, IR spectroscopy, and H-1, C-13, and B-11 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 (C) 2003 John Wiley Sons, Ltd.