Grubbs-Hoveyda type catalysts bearing a dicationic N-heterocyclic carbene for biphasic olefin metathesis reactions in ionic liquids

Abstract

The novel dicationic metathesis catalyst [(RuCl2(H2ITapMe2)(=CH-2-(2-PrO)-C6H4))2+(OTf-)2] (Ru-2, H2ITapMe2 = 1,3-bis(2',6'-dimethyl-4'-trimethylammoniumphenyl)-4,5-dihydroimidazol-2-ylidene, OTf- = CF3SO3-) based on a dicationic N-heterocyclic carbene (NHC) ligand was prepared. The reactivity was tested in ring opening metathesis polymerization (ROMP) under biphasic conditions using a nonpolar organic solvent (toluene) and the ionic liquid (IL) 1-butyl-2,3-dimethylimidazolium tetrafluoroborate [BDMIM+][BF4-]. The structure of Ru-2 was confirmed by single crystal X-ray analysis.