Pd catalysts immobilized onto gel-supported ionic liquid-like phases (g-SILLPs): A remarkable effect of the nature of the support

New polymeric materials containing functional sites analogous to ionic liquids have been synthesized. Those materials are a supported reservoir for the active Pd species. Their catalytic activity has been evaluated for the Heck reaction proving an excellent performance in terms of both activity and recyclability. Although soluble Pd species seem to participate in the catalytic cycle, as for many other supported Pd-systems, the g-SILLPs present the ability to efficiently release and recapture those soluble species. This allows to dramatically reduce or eliminate the amount of I'd leached to the final solution, in particular at higher temperatures, and opens the way, based on a release and catch strategy, for the development of active-supported Pd catalytic systems, easily recoverable and reusable for a large number of catalytic cycles. The exact nature of the polymer (SILLPs) has a remarkable influence on the overall process. The appropriate design of the g-SILLPs is a key factor for the optimization of the release and catch system. The functionalized polymers prepared can be reused for a significant number of catalytic cycles without any loss in performance. (c) 2009 Elsevier Inc. All rights reserved