Sulfonate- or carboxylate-functionalized N-heterocyclic bis-carbene ligands and related water soluble silver complexes

Abstract

New N-heterocyclic carbene ligand precursors {H₂C(HTz^R)₂} and {H₂C(HIm^R)₂} (HTz = 1,2,4-triazole; HIm = imidazole; R = PrSO₃ or EtCOO) were obtained starting from the compounds bis(1,2,4-triazol-1-yl)methane and bis(imidazol-1-yl)methane. The related silver(I) carbene complexes were prepared in degassed water solution by treatment of the triazolium or imidazolium species with Ag₂O, resulting in well-characterized and water soluble bimetallic complexes of general formula {Na₂[H₂C(Tz^R)₂]₂Ag₂} and {Na₂[H₂C(Im^R)₂]₂Ag₂}. In these metallacycles every silver atom is coordinated to two triazolin- or imidazolin-2-ylidene rings, belonging to two different dicarbene units.