Synthesis and characterization of silver(I), gold(I), and gold(III) complexes bearing a bis-dialkylamino functionalized N-heterocyclic carbene

Bis-1,3-[2-(diisopropylamino)ethyl]-imidazolium chloride, 1, has been prepared and used as a precursor for the synthesis of the corresponding silver(I) chloride complex 2. The single crystal structure analysis reveals that the complex dimerizes in the solid state. Transmetalation of 2 with (tht)AuBr (tht = tetrahydrothiophene) yields the (NHC)Au(I)Br complex 3. By treatment with bromine it is oxidized to (NHC)AuBr3, 4, which is obtained as a yellow, microcrystalline powder. The UV–vis spectra of 4 are dependent on the pH-value and suggest a square-pyramidal structure in solution.

The silver(I) complex (NHC)AgCl, 2, [(NHC) = bis-1,3-[2-(diisopropylamino)ethyl]-imidazol-2-ylidene] has been prepared and structurally characterized. Transmetalation and oxidation with Br2 yield the complexes (NHC)Au(I)Br, 3, and (NHC)AuBr3, 4, respectively. The UV–vis spectra of 4 are dependent on the pH-value and suggest a square-pyramidal structure in solution.Figure optionsDownload as PowerPoint slideHighlights
► A bis-dialyklamino functionalized imidazolium salt was prepared and used as a precursor for the corresponding Ag(I) complex.
► Transmetalation and oxidation yields the Au(I) and Au(III) bromides.
► UV–vis spectra of the Au(III) complex is pH-dependent and suggest a square-pyramidal coordination in solution.