Blue and highly emitting [Ir(IV)] complexes by an efficient photoreaction of yellow luminescent [Ir(III)] complexes

A family of cyclometalated [Ir(III)] complexes containing two F2ppy ligands and a bis-oxazoline (box) ancillary ligand, either chiral (1) or achiral (2) has been synthesized. They exhibit photophysical and electrochemical properties quite similar to the isoelectronic and well known [Ir(F2ppy)2(acac)] complex. However, an unprecedented photoreactivity has been observed. Upon UV irradiation of air-equilibrated solutions of both complexes, stable photoproducts containing an [Ir(IV)] metal center are obtained. The photoproducts exhibit highly efficient blue luminescence with good OLED performances. The same [Ir(IV)] complexes are obtained also by electrochemical oxidation.