Synthesis and Structural Characterization of N-Heterocyclic Carbene Complexes of Silver(I) and Rhodium(I) from Caffeine

Aysegul Kascatan-Nebioglu, Matthew J. Panzner, Jered C. Garrison, Claire A. Tessier, Wiley J. Youngs

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The imidazolium cation 1,3,7,9-tetramethylxanthinium methyl sulfate (1a) is obtained by the reaction of caffeine with dimethyl sulfate. The anion exchange of la gives 1,3,7,9-tetramethylxanthinium hexafluorophosphate (1b). Ligand 1a reacts with Ag 2O in water to yield an N-heterocyclic carbene (NHC) silver(I) complex (2a). Similarly, ligand 1b reacts with Ag 2O in DMSO to yield NHC silver(I) complex 2b in high yield. A carbene transfer reaction of 2b with [Rh(COD)Cl]2 gives NHC Rh(I) complex 3. All compounds were characterized by 1H NMR, 13C NMR, and mass spectrometry. The solid-state structures of 1b, 2b, and 3 were determined by X-ray crystallography.

Original languageEnglish (US)
Pages (from-to)1928-1931
Number of pages4
Issue number8
Publication statusPublished - Apr 12 2004


ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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