Synthesis, properties, DFT calculations, and cytotoxic activity of phosphorescent iridium(III) complexes with heteroatom ancillary ligands

Three new cyclometalated iridium(III) complexes [(cf(3)piq)(2)Ir((NN)-N-perpendicular to)][PF6] (Ir1-Ir3) have been synthesized and characterized. The solid structure ofIr1has been determined by X-ray crystallography. The structure-property relationships of these complexes have been discussed by spectroscopic, computational, and electrochemical studies. Thein vitrocytotoxic activity ofIr1-Ir3against cancer SGC-7901, A431, and HeLa cells was evaluated by MTT method. Thein vitrogrowth inhibition assays exhibitedIr2andIr3had better potency than that of cisplatin. Further, the fluorescence microscopy images revealed thatIr2andIr3could be present in the cell and make changes in cell morphology. The results showed that iridium complexes with S/O-heteroatom ancillary ligands have strong anticancer activities and good cell imaging properties.