Allyl‐Functionalised Ionic Liquids: Synthesis, Characterisation, and Reactivity

The two known Me‐ and allyl‐substituted 1 H ‐imidazol‐3‐ium bromides 1 and 2 , respectively, were converted to the corresponding BF $\rm{_{4}^{-}}$ and BPh $\rm{_{4}^{-}}$ salts 3 – 6 ( Scheme 1 ). Compounds 3 and 4 were liquids at ambient temperature. Reaction of 1 or 2 with [PdCl 2 ] afforded the corresponding 2 : 1 imidazolium/metal complexes 7 and 8 . The latter complex, melting at 58°, can be regarded as a ‘true’ ionic liquid. Attempts to polymerise 7 by radical promotion (AIBN) were unsuccessful, but resulted in the centrosymmetric 2 : 1 complex 9 . The allyl group of 1 could be arylated (giving rise to 10 ) or hydrogenated (at 100 bar H 2 pressure). The solid‐state structures of compounds 5 – 7 and 9 were solved by means of single‐crystal X‐ray analyses ( Figs. 1–4 ).