Orotate containing anionic luminescent iridium(III) complexes and their use in soft salts

Two anionic iridium complexes [(R-ppy)(2)Ir(O<^>N)]TBA with R-ppy = 2-phenylpyridine or 4,5'-dimethyl-2-phenylpyridine, O<^>N = dianionic form of orotic acid and TBA = tetrabutylammonium have been synthesised and fully characterised by UV-Vis, emission, IR, NMR and cyclic voltammetric studies. These cyclo-metallated luminescent complexes containing a dianionic bidentate ancillary ligand show bright emission (60-70% PLQY) with maxima in the green region of the visible spectrum. Coupled with the ionic iridium complexes [(ppy)(2)Ir(N<^>N)]X, where N<^>N = 2-picolylamine or 2,2'-bipyridyl, and X = Cl- or CH3CO2-, a series of new soft salts of general formula [(ppy)(2)Ir(N<^>N)][(R-ppy)(2)Ir (O<^>N)] have been obtained and fully characterized, with enhanced luminescent properties up to ca. 80% of phosphorescence quantum yields.