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

Abstract

Abstract The novel, low‐melting‐point (19 °C) salt [ N ‐pentylpyridinium] + [ closo ‐CB 11 H 12 ] − (2) was synthesized in 93% yield and characterized by elemental analysis, IR spectroscopy, and 1 H, 13 C, and 11 B 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 PdCl 2 (PPh 3 ) 2 , PdCl 2 (dppe), and PdCl 2 (dppf). Complete debromination of C 6 Br 6 , 1,2,4,5‐tetrabromobenzene, C 60 Br 8 , and C 60 Br 24 was accomplished quite rapidly, whereas dechlorination of 1,2,4‐trichlorobenzene proceeded more slowly, but with excellent products selectivity. Copyright © 2003 John Wiley &amp; Sons, Ltd.