Bipyridine-based iridium(iii) triplet emitters for organic light-emitting diodes (OLEDs): application and impact of phenyl substitution at the 5'-position of the N-coordinating pyridine ring.

Three blue phosphorescent homoleptic iridium(iii) complexes based on a bipyridine ligand were synthesized. The structures of these Ir(C^N)3 analogues were determined by single-crystal X-ray diffraction analysis. Two geometrical isomers, facial and meridional, formed as the major products, and the ratio of the products depended on the substituents.