Cross-Linked Imidazolium Salts as Scavengers for Palladium
- Authors: Buscemi, R.; Giacalone, F.; Orecchio, S.; Gruttadauria, M.
- Publication year: 2014
- Type: Articolo in rivista (Articolo in rivista)
- OA Link: http://hdl.handle.net/10447/90165
Five imidazolium-based materials have been synthesised and used for the first time as palladium scavengers. Radical reactions of suitable bis-vinylimidazolium salts led to a series of insoluble materials through homo-polymerisation, immobilisation with a 3-mercaptopropyl-modified silica gel or co-polymerisation with ethylene glycol dimethylacrylate. These materials were screened as palladium scavengers with a set of palladium(0) and palladium(II) compounds in different solvents and at different starting amounts of palladium. In many cases, residual amounts of palladium were lower than 5 ppm, as requested for the manufacture of active pharmaceutical ingredients and fine chemicals. The application of one of these materials as a palladium scavenger in a Suzuki coupling reaction resulted in a 29-fold abatement of the palladium content in the final product with respect to the control reaction.