How to blue-shift phosphorescence color of iridium(III) complexes

We achieve a 20-58 nm (610-1890 cm (1)) blue-shift of the phosphorescence maximum of iridium(III) complexes (CN)(2)Ir(NN) of 1,10-phenanthrolines (NN) by modifying the cyclometalating 2-phenylpyridine ligand (CN = ppy) with an electron-withdrawing 4'-fluoro or 4'-trifluoromethyl group or by replacing the pyridine in ppy with a pyrazole. New complexes exhibit green or yellow phosphorescence in argon-saturated 10 (5) M dichloromethane solution at room temperature with a maximum at 525-563 nm, quantum yield of 54-68%, and excited-state lifetime of 1.1-2.7 mu s. (C) 2012 Elsevier B.V. All rights reserved.