Phosphorescent Ir(III) complexes derived from purine nucleobases.

We report the preparation and the study of new types of neutral and cationic phosphorescent heteroleptic Ir(III) complexes derived from 6-phenylpurine nucleosides and nucleotides. Neutral complexes of general formula Ir(C^N) 2 (acac) 7, and 8a-c (HC^N = 9-substituted-6-phenyl purine) are orange-red emissive upon photoexcitation, with short lifetimes and good quantum yields (0.42-0.65) in both PMMA films and 2-MeTHF at room temperature. In turn, cationic complexes [Ir(C^N) 2 (dtb-bpy)][PF 6 ] 9, 12a and 12c (dtb-bpy = 4,4'-di- tert -butyl-2,2'-dipyridine) are yellow-green emitters with moderate quantum yields (0.24-0.32).