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 Ag(2)O 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.