Synthesis and Characterization of Water-Soluble Silver and Palladium Imidazol-2-ylidene Complexes with Noncoordinating Anionic Substituents

Zwitterionic imidazolium salts have been synthesized bearing alkylsulfonate and alkylcarboxylate
substituents and used as precursors to water-soluble metal−carbene complexes. Reaction of the zwitterionic
imidazolium compounds with Ag2O gave bis(imidazol-2-ylidene)silver complexes. These compounds
have been characterized spectroscopically and by electrospray mass spectrometry. A DMSO solvate of
bis[1-(2,6-diisopropylphenyl)-3-(3-sulfonatopropyl)imidazol-2-ylidene]silver sodium salt has been structurally characterized. In the solid state, this complex exists as a coordination polymer in which the sodium
ions bridge the sulfonate groups from two bis(imidazol-2-ylidene)silver moieties. Diiodobis[1-mesityl-3-(3-sulfonatopropyl)imidazol-2-ylidene]palladium disodium salt has also been prepared in low yield
and characterized by NMR spectroscopy and electrospray mass spectrometry.