Ruthenium Salen/phenyltrimethylammonium tribromide catalyzed coupling reaction of carbon dioxide and epoxides

The coupling reaction of CO2 and epoxides can be carried out in the absence of solvent under mild conditions by using novel and recycled catalysts of SalenRu(II)(PPh3)2/PTAT or SalenRu(III)X(PPh3)/PTAT (X = Cl−, OAc−, ClO4-, NO3-).