Bis-N-heterocyclic carbene ‘pincer’ ligands and iridium complexes with CF3 – Substituted phenylene backbone

• Bis-NHC chemistry.
• Pincer complexes with an anionic CNHCCCNHC tridentate ligand bearing CF3-substituents.
• Iridium(III) pincer-type complexes.

With the aim to favour formation of ‘pincer’-type IrIII complexes containing two NHC donor moieties, we have used a pro-ligand with a bis-CF3-substituted phenylene backbone in order to prevent unwanted backbone cyclometallation. The potential of this new ‘pincer’ pro-ligand, 1,1′-(4,6-bis(trifluoromethyl)-1,3-phenylene)bis(3-butyl-1H-imidazol-3-ium) iodide (3), is demonstrated by the synthesis and structural characterisation of the ‘pincer’ IrIII bis carbene benzenide complex (4).

CF3-substitution favours formation of a CNHCCCNHC ‘pincer’-type IrIII complex.Figure optionsDownload as PowerPoint slide