A Novel Carbene Ruthenium Complex as Reusable and Selective Two-Electron Catalyst for Alkene Epoxidation

A new ruthenium aquo catalyst with the formula trans-[Ru(II)(CN-Me)(trpy)OH2](PF6)(2) [where trpy = 2,2':6',2 ''-terpyridine and CN-Me= 3-methyl-1-(pyridin-2-yl)-imidazolylidene] has been prepared and thoroughly characterized by spectroscopic and electrochemical techniques. The complex has been tested in epoxidation catalysis both in dichloromethane and dichloromethane: ionic liquid media, displaying excellent performances and selectivities. Reuse of the catalyst in ionic liquid: solvent media has been explored for the first time in ruthenium-mediated epoxidation catalysis and its performance is fully maintained for up to ten runs.