Microwave synthesis of dirhenium paddlewheel complexes

Tetrakis(carboxylato)dihalidodirhenium (III,III) complexes were efficiently synthesized utilizing microwave irradiation. Re2(acetate)4X2, Re2(butyrate)4X2 and Re2(pivalate)4X2, where X = Cl or Br, were produced in under one hour in the microwave with comparable yields to traditional refluxes which take as long as four days. All reaction samples were prepared under inert gas and the septa caps of the microwave reaction vessels were sufficient to maintain this environment during the reaction. Re2(acetate)4X2 and Re2(butyrate)4X2 were synthesized from the (Bu4N)2[Re2X8] salt, the acid, the anhydride, and in some cases hexanes. Re2(pivalate)4X2, traditionally prepared via melt reactions, were synthesized from the (Bu4N)2[Re2X8] salt and pivalic acid combined in diglyme or diglyme and hexanes.