η 1 ‐Arene Complexes as Intermediates in the Preparation of Molecular Phosphorescent Iridium(III) Complexes

Molecular phosphorescent heteroleptic bis‐tridentate iridium(III) emitters have been prepared via η 1 ‐arene intermediates. In the presence of 4.0 mol of AgOTf, the complex [(IrCl{κ 3 ‐ N , C , N ‐(pyC 6 HMe 2 py)})( μ ‐Cl)] 2 ( 1 ; pyC 6 H 2 Me 2 py=1,3‐di(2‐pyridyl)‐4,6‐dimethylbenzene) reacted with 9‐(6‐phenylpyridin‐2‐yl)‐9 H ‐carbazole (PhpyCzH) and 2‐phenoxy‐6‐phenylpyridine (PhpyOPh) to give [Ir{κ 3 ‐ N , C , N ‐(pyC 6 HMe 2 py)}{κ 3 ‐ C , N , C′ ‐(C 6 H 4 pyCzH)}]OTf ( 2 ) and [Ir{κ 3 ‐ N , C , N ‐(pyC 6 HMe 2 py)}{κ 3 ‐ C , N , C′ ‐(C 6 H 4 pyOPh)}]OTf ( 3 ). The X‐ray diffraction structures of 2 and 3 reveal that the carbazolyl and phenoxy substituents of the C,N,C′ ligand coordinate to the metal center to form an η 1 ‐arene π bond. Treatment of 2 and 3 with KO t Bu led to the deprotonation of the coordinated carbon atom of the η 1 ‐arene group to afford the molecular phosphorescent [5t+4t′] heteroleptic iridium(III) complexes [Ir{κ 3 ‐ N , C , N ‐(pyC 6 HMe 2 py)}{κ 3 ‐ C , N , C′ ‐(C 6 H 4 pyCz)}] ( 4 ) and [Ir{κ 3 ‐ N , C , N ‐(pyC 6 HMe 2 py)}{κ 3 ‐ C , N , C′ ‐(C 6 H 4 pyOC 6 H 4 )}] ( 5 ). These complexes are green emitters that display short lifetimes and high quantum yields of 0.73 ( 4 ) and 0.87 ( 5 ) in the solid state.