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

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.