Anionic cyclometallated iridium(III) complexes containing substituted bivalent ortho-hydroquinones

• New Ir(III) anionic complexes containing chelating O^O ortho-hydroquinones
• High reversibility of the first oxidation process
• Strong absorption extending as far as 700 nm

The straightforward synthesis, redox and photophysical properties of a series of Ir(III) complexes of general formula [(ppy)Ir(O^O)]NBu4, (1–3) where ppy is 2-phenylpyridine and O^O are tetrachlorocatecholate (1), tetrabromocatecholate (2) or alizarinate (3) in their dianionic forms, are reported.

The synthesis and structural characterisations of new Ir(III) anionic complexes containing bivalent functionalized cathecolate ligands are described. An intensive electrochemical investigation showed the high stability of the first oxidation process. Remarkably, the complex containing the alizarine dye is one of the few Ir(III) complexes reported so far that has strong absorption extending as far as 700 nm. The complexes described herein give access to a pool of similar compounds within the large class of ortho-hydroquinone based dyes, highly interesting for electrochromic, redox switchable and sensor materials.Figure optionsDownload as PowerPoint slide