Syntheses, crystal structures and phosphorescence properties of cyclometalated iridium(III) bis(pyridylbenzaldehyde) complexes with dithiolate ligands

Abstract

Abstract The synthesis of three neutral bis-cyclometalated iridium(III) complexes [Ir(pba)2(S^S)] (pbaH=4-(2-pyridyl)benzaldehyde; S^S=Et2NCS2 − (1), iPrOCS2 − (2), (nPrO)2PS2 − (3)) from [{Ir(μ-Cl)(pba)2}2] and the corresponding sodium or potassium dithiolates in methanol-dichloromethane is described. The composition of complexes 1–3 is discussed on the basis of 1H NMR, 13C NMR, IR, and mass spectroscopy, and the crystal structures of 1 and 3 were determined by X-ray crystallography. The absorption and emission spectra show that the [Ir(pba)2(S^S)] complexes may be effective candidates as green-emitting phosphorescent materials. The stability of the three cyclometalated iridium(III) complexes towards different transition metal ions was also investigated in acetonitrile-water solvent.