New N-heterocyclic carbene mercury(II) complexes: Close mercury–arene interaction

Mononuclear mercury complexes (1, 2, and 3) bearing bis-N-heterocyclic carbene (NHC) ligands of the form [(NHC)2-μ-Hg]+2 have been prepared and structurally characterised. The complexes were derived from three bis-imidazolium salts as precursors to NHC; either 1,3-bis(N-methylimidazolium-1-ylmethyl)benzene bis(hexafluorophosphate) (I·2PF6), 1,3-bis(N-butylimidazolium-1-ylmethyl)benzene bis(hexafluorophosphate) (II·2PF6) or 3,5-bis(N-butylimidazolium-1-ylmethyl)toluene bis(hexafluorophosphate) (III·2PF6) treated with mercury(II) acetate. Interestingly X-ray crystal structure analysis revealed a close interaction between the Hg metal centre with one carbon atom of the aryl linker in addition to coordination with two NHCs.

A new mercury(II)–N-heterocyclic carbene (NHC) complexes of 1,3-bis(3-methyl-imidazolium-1-ylmethyl)benzenemercury(II) bis(hexafluorophosphate) (1), 1,3-bis(3-butyl-imidazolium-1-ylmethyl)benzenemercury(II) bis(hexafluorophosphate) (2) and 3,5-bis(3-butylimidazolium-1-ylmethyl)toluenemercury-(II) bis(hexafluorophosphate) (3) were synthesized and characterized. The structural studies revealed a close interaction between the Hg metal centre with one carbon atom of the aryl linker in addition to coordination with two NHCs.Figure optionsDownload as PowerPoint slideHighlights
► Three new mercury(II)-N-heterocyclic carbene complexes were synthesized.
► The synthesized complexes were characterized by 1H, 13C NMR, CHN analysis and X-ray crystallography.
► X-ray studies revealed a close interaction between the mercury and one carbon atom from the aryl linker.