One-pot synthesis of homoleptic iridium (III) dyes created using alkoxo-functionalized bipyridine ligands and these dyes' applications for organic light-emitting diodes

A facile, one-pot synthetic method to prepare alkoxo-functionalized homoleptic cyclometalated Ir (III) compounds with facial geometry has been developed. The reaction of Ir(COD)(2)BE4 with two bipyridine ligands, 2',6'-dimethoxy-4-methyl-2,3'-bipyridine and 2',6',4-trimethoxy-2,3'-bipyridine, afforded the homoleptic Ir (III) compounds Ir[(RO)(2)(Me)pypy](3) (1) and Ir[(RO)(3)pypy](3) (2) in good yields. The reaction conditions highly selectively produced the aforementioned Ir (III) compounds with facial geometry. The decomposition temperatures of 1 and 2 were 387 degrees C and 368 degrees C, respectively. Both compounds exhibited intense blue phosphorescence (lambda(max) = 452-458 nm) with excellent quantum efficiencies (Phi(PL) = 0.45 -0.52). Phosphorescent organic light-emitting diodes (PHOLEDs) that used these compounds as the dopant material and 9-(3-(9H-carbazol-9-yl)phenyl)-9H-carbazol-3-yl)diphenylphosphine oxide as the host material have been fabricated. The electroluminescent device created using compound 1 at a doping level of 5 wt% exhibited the best performance, with an external quantum efficiency of 15.7-15.5% at a brightness of 10-100 cd/m(2) and color coordinates of (0.16, 0.28) at 100 cd/m(2). (C) 2016 Elsevier Ltd. All rights reserved.