| Sumario: | The preparation and photophysical properties of heteroleptic iridium(III) complexes containing a dianionic C, C, C, C-tetradentate ligand and a cyclometalated phenylpyridine group are described. Complex [Ir(µ-OMe)(COD)]2 (1, COD = 1, 5-cyclooctadiene) reacts with 1, 1-diphenyl-3, 3-butylenediimidazolium iodide ([PhIm(CH2)4ImPh]I2), in the presence NaOtBu, to give [Ir(µ-I){¿4-C, C, C, C-[C6H4Im(CH2)4ImC6H4]}]2 (2), which leads to {[Ir{¿4-C, C, C, C-[C6H4Im(CH2)4ImC6H4]}]2(µ-OH)(µ-OMe)} (3) by treatment first with silver trifluoromethanesulfonate (AgOTf) in acetone-dichloromethane and subsequently with KOH in methanol. The reaction of 2 with AgOTf and acetonitrile affords the bis(solvento) complex [Ir{¿4-C, C, C, C-[C6H4Im(CH2)4ImC6H4]}(CH3CN)2]OTf (4). The latter promotes the pyridyl-supported heterolytic ortho-CH bond activation of the phenyl group of 2-phenylpyridine, 2-(2, 4-difluorophenyl)pyridine, 2-(p-tolyl)pyridine, and 5-methyl-2-phenylpyridine to yield Ir{¿4-C, C, C, C-[C6H4Im(CH2)4ImC6H4]}{¿2-C, N-[Ar-py]} (Ar-py = C6H4-py (5), C6H2F2-py (6), C6H3Me-py (7), C6H4-Mepy (8)) using (piperidinomethyl)polystyrene as an external base. Complexes 5-8 are blue-green emitters, which display short lifetimes (0.6-4.8 µs) and quantum yields close to unity in both doped poly(methyl methacrylate) films at 5 wt % and in 2-methyltetrahydrofuran at room temperature.
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