Evaluation of ionic liquid soluble imidazolium tetrachloropalladate pre-catalysts in Suzuki coupling reactions

Imidazolium salts with aromatic groups 1,3-bis(9-anthracenylmethyl)imidazolium chloride ([Bamim]Cl), 1,3-bis(1-naphthalenylmethyl)imidazolium chloride ([Bnmim]Cl) and 1,3-bis(benzylmethyl)imidazolium chloride ([Bbmim]Cl) were reacted with PdCl2 forming the analogous tetrachloropalladate salts. These palladium-containing salts were evaluated as pre-catalysts in Suzuki cross-coupling reactions in ionic liquids generally resulting in high conversions. The formation of palladium nanoparticles is observed and their role in the overall catalytic mechanism is discussed.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (177 K)Download as PowerPoint slideHighlights► Three imidazolium tetrachloropalladates were synthesized and crystal structures identified. ► They proved to be active pre-catalyst for Suzuki reactions. ► The effect of cations on the efficiency of the reaction were studied and rationalized.