Photophysical and Electrochemical Properties of Blue Phosphorescent Iridium(III) Complexes

Abstract

A series of 2-difluorophenyl-4-methoxypyridine ligands were synthesized and successfully used to prepare iridium complexes including bis[2-(2‘,3‘-difluorophenyl)-4-methoxypyridinato-N,C2‘]iridium(III) [5-(2‘-pyridyl)tetrazolate] (5a1), bis[2-(2‘,4‘-difluorophenyl)-4-methoxypyridinato-N,C2‘]iridium(III) [5-(2‘-pyridyl)tetrazolate] (5a2), bis[2-(2‘,5‘-difluorophenyl)-4-methoxypyridinato-N,C2‘]iridium(III) [5-(2‘-pyridyl)tetrazolate] (5a3), bis[2-(3‘,4‘-difluorophenyl)-4-methoxypyridinato-N,C2‘]iridium(III) [5-(2‘-pyridyl)tetrazolate] (5a4), and bis[2-(3‘,5‘-difluorophenyl)-4-methoxypyridinato-N,C2‘]iridium(III) [5-(2‘-pyridyl)tetrazolate] (5a5). Interestingly, 5a4 exhibits 2‘-coordinated and 6‘-coordinated isomers. The coordination behavior of this ligand with iridium metal differed depending on the repulsion energy and the delocalization energy effects of the iridium complexes. X-ray structural analysis technique was successfully applied to interpret the different coordination behavior of 5a4. In addition,...