Patent ID: 7687635

Claim:
A five-coordinate metal complex, a salt, or an enantiomer thereof, comprising a metal selected from the group consisting of ruthenium and osmium, a carbene ligand selected from the group consisting of an allenylidene ligand, a cumulenylidene ligand, an indenylidene ligand and a phenylindenylidene ligand, a multidentate ligand and one or more other ligands, wherein at least one of said other ligands is a constraint steric hindrance ligand having a pKa of at least 15, said constraint steric hindrance ligand being a non-ionic prophosphatrane superbase or a N-heterocyclic carbene selected from the group consisting of imidazol-2-ylidene, dihydroimidazol-2-ylidene, oxazol-2-ylidene, triazol-5-ylidene, thiazol-2-ylidene, bis(imidazoline-2-ylidene) bis(imidazolidine-2-ylidene), pyrrolylidene, pyrazolylidene, dihydropyrrolylidene, and pyrrolylidinylidene and benzo-fused N-heterocyclic carbenes, wherein said benzo-fused N-heterocyclic carbene comprises a heterocyclic ring fused to a benzene ring and said heterocyclic ring is selected from the group consisting of imidazol-2-ylidene, dihydroimidazol-2-ylidene, oxazol-2-ylidene, triazol-5-ylidene, thiazol-2-ylidene, bis(imidazoline-2-ylidene) bis(imidazolidine-2-ylidene), pyrrolylidene, pyrazolylidene, dihydropyrrolylidene, and pyrrolylidinylidene, and wherein one or more hydrogen atoms of said non-ionic prophosphatrane superbase or said N-heterocyclic carbene is substituted with a group providing constraint steric hindrance.