A water-soluble palladium-salen catalyst modified by pyridinium salt showing higher reactivity and recoverability for Heck coupling reaction

A novel and water-soluble palladium-salen catalyst modified by pyridinium salt was synthesized and characterized by NMR, HRMS, FF-IR, ICP, elemental analysis and UV-vis spectroscopy. The catalyst can efficiently catalyze the Heck reaction between aryl halides and olefins. The reaction using 0.5 mol% catalyst can achieve 98.3% conversion with 99% selectivity. The catalytic activity of catalyst modified by pyridinium salt is higher than that of un-modified one. Furthermore, the catalyst can be easily separated from reaction system by water wash and subsequently recycled for six runs without significant loss of activity and selectivity. (C) 2014 Elsevier B.V. All rights reserved.