| Sumario: | 1-Phenyl-3-(1-phenyl-1-(pyridin-2-yl)ethyl)isoquinoline (H2MeL) has been prepared by Pd(N-XantPhos)-catalyzed "deprotonative cross-coupling processes"to synthesize new phosphorescent red iridium(III) emitters (601-732 nm), including the carbonyl derivative Ir(¿4-cis-C, C'-cis-N, N'-MeL)Cl(CO) and the acetylacetonate compound Ir(¿4-cis-C, C'-cis-N, N'-MeL)(acac). The tetradentate 6e-donor ligand (6tt') of these complexes is formed by two different bidentate units, namely, an orthometalated 2-phenylisoquinoline and an orthometalated 2-benzylpyridine. The link between the bidentate units reduces the number of possible stereoisomers of the structures [6tt' + 3b] (3b = bidentate 3e-donor ligand), with respect to a [3b + 3b' + 3b¿] emitter containing three free bidentate units, and it permits a noticeable stereocontrol. Thus, the isomers fac-Ir(¿4-cis-C, C'-cis-N, N'-MeL){¿2-C, N-(C6H4-py)}, mer-Ir(¿4-cis-C, C'-cis-N, N'-MeL){¿2-C, N-(C6H3R-py)}, and mer-Ir(¿4-trans-C, C'-cis-N, N'-MeL){¿2-C, N-(C6HR-py)} (R = H, Me) have also been selectively obtained. The new emitters display short lifetimes (0.7-4.6 µs) and quantum yields in a doped poly(methyl methacrylate) film at 5 wt % and 2-methyltetrahydrofuran at room temperature between 0.08 and 0.58. The acetylacetonate complex Ir(¿4-cis-C, C'-cis-N, N'-MeL)(acac) has been used as a dopant for a red PhOLED device with an electroluminescence ¿max of 672 nm and an external quantum efficiency of 3.4% at 10 mA/cm2. © 2021 American Chemical Society.
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