Photophysical and electrochemical properties of heteroleptic tris-cyclometallated Ir(III) complexes

Some new heteroleptic tris-cyclometallated iridium(III) complexes have been synthesized and fully characterized. Among these iridium(III) complexes, bis(1-phenylpyrazolato-N,C2′)iridium(III)[5-(2′-pyridyl)tetrazolate] (3) and bis(3-methyl-1-phenylpyrazolato-N,C2′)iridium(III)[5-(2′-pyridyl)tetrazolate] (4) show excellent quantum yields at room temperature, the electron density being perturbed by introducing the pyridyltetrazole ligand, making kr > knr. This destroys the concept of phenylpyrazole based iridium complexes.

Graphical abstractNovel heteroleptic tris-cyclometallated iridium(III) complexes have been synthesized and fully characterized. The photophysical and electrochemical properties of these iridium complexes have been investigated. Although bis(1-phenylpyrazolato-N,C2′)iridium(III)[5-(2′-pyridyl)tetrazolate] (3) and bis(3-methyl-1-phenylpyrazolato-N,C2′)iridium(III)[5-(2′-pyridyl)tetrazolate] (4) undergo a quasi-reversible oxidation, they show excellent quantum yields at room temperature.Figure optionsDownload full-size imageDownload as PowerPoint slide