Syntheses and crystal structures of 1-methyl-3-difluoromethylbenz-imidazolium NHC complexes with different transition metals

• N-Difluoromethyl containing NHC complexes of Pd, Ni, Hg and Ag were synthesized.
• The complexes were characterized by NMR spectra and X-ray diffraction analysis.
• Despite of instability of corresponding free carbenes, their complexes with metals are very stable.

1-Methyl-3-difluoromethylbenzimidazolium salts were synthesized as key precursors for N-difluoromethyl containing NHC (N-heterocyclic carbene) ligands. The complexes with such ligands and several transition metals were synthesized and characterized by 1H, 19F NMR spectra and X-ray diffraction analysis. Palladium chloride reacts with the corresponding benzimidazolium hexafluorophosphate in the presence of sodium acetate to form the complex containing chlorine atoms. Nickel acetate reacts with the corresponding benzimidazolium iodide to form the complex containing two iodine atoms. Silver and mercury complexes were obtained from the benzimidazolium salts with non-nucleophilic anions (NTf2−, PF6−) and the corresponding metal acetates or oxides.

The first N-difluoromethyl containing NHC (N-heterocyclic carbene) complexes with several transition metals, namely Pd, Ni, Hg and Ag were synthesized and characterized by 1H, 19F NMR spectra and X-ray diffraction analysis.Figure optionsDownload as PowerPoint slide