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

Abstract

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.

Water‐Soluble IrIII N‐Heterocyclic Carbene Based Catalysts for the Reduction of CO2 to Formate by Transfer Hydrogenation and the Deuteration of Aryl Amines in Water

“…Synthesis and characterization of new compounds: To obtain water-soluble Ir III A C H T U N G T R E N N U N G (bis-NHC) complexes, we used the two sulfonate-functionalized bis-imidazolium salts, which were prepared according to the general strategy used by us [10] and others, [11] consisting of the reaction of the corresponding neutral bisimidazoles with propanesultone. The Ir III complexes 2 and 3 were obtained by reaction of the corresponding sulfonate-functionalized bisimidazolim salts with [IrClA C H T U N G T R E N N U N G (cod)] 2 (COD = 1,5-cyclooctadiene) in the presence of KI and NaOAc in refluxing MeOH.…”

Recent Developments in the Applications of Palladium Complexes Bearing N-Heterocyclic Carbene Ligands

“…Pursuing the preparation of hydrophilic metal complexes, Shaughnessy and Schanz described the synthesis and coordination of imidazolium precursors bearing alkylsulfonate and alkylcarboxylate Nsubstituents. 58 Scheme 6 illustrates the synthesis of the carboxylate and sulfonate zwitterionic imidazolium salts and the coordination of the latter to Pd(II). …”

Ammonium‐Salt‐Tagged IMesAuCl Complexes and Their Application in Gold‐Catalyzed Cycloisomerization Reactions in Water

“…[5][6][7] Nevertheless, their application was limited to homogeneous catalysis in organic solvents for more than a decade. Since then, reports about their linkage to water-soluble polymers [8,9] or silica-based surfaces, [9] their introduction into carbohydrates, [10] and their functionalization with hydrophilic groups, such as carboxylate [11,12] or sulfonate, [12] have been reported. [13] The objective of these latter studies was an improved water solubility which would lead to an easier separation of product and catalyst, and ultimately even the opportunity of catalyst recycling.…”