Synthesis and structural characterization of metal complexes based on pyrazole/imidazolium chlorides

A series of imidzoalium salt, L · HCl, for the potentially bidentate pyrazole/N-heterocyclic carbene was synthesized. Structural determinations reveal that compounds based on pyrazole/imidazolium chloride L · HCl adopt gauche conformation exclusively in the solid state. Palladium complexes of L · HCl are active Heck catalysts.