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Molecular phosphorescent heteroleptic bis-tridentate iridium(III) emitters have been prepared via η1-arene intermediates. In the presence of 4.0 mol of AgOTf, the complex [(IrCl{κ3-N,C,N-(pyC6HMe2py)})(μ-Cl)]2 (1; pyC6H2Me2py=1,3-di(2-pyridyl)-4,6-dimethylbenzene) reacted with 9-(6-phenylpyridin-2-yl)-9H-carbazole (PhpyCzH) and 2-phenoxy-6-phenylpyridine (PhpyOPh) to give [Ir{κ3-N,C,N-(pyC6HMe2py)}{κ3-C,N,C′-(C6H4pyCzH)}]OTf (2) and [Ir{κ3-N,C,N-(pyC6HMe2py)}{κ3-C,N,C′-(C6H4pyOPh)}]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 η1-arene π bond. Treatment of 2 and 3 with KOtBu led to the deprotonation of the coordinated carbon atom of the η1-arene group to afford the molecular phosphorescent [5t+4t′] heteroleptic iridium(III) complexes [Ir{κ3-N,C,N-(pyC6HMe2py)}{κ3-C,N,C′-(C6H4pyCz)}] (4) and [Ir{κ3-N,C,N-(pyC6HMe2py)}{κ3-C,N,C′-(C6H4pyOC6H4)}] (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., Financial support from the Spanish Ministerio de Economía y Competitividad (MINECO) (Projects CTQ2014-52799-P, Red de Excelencia Consolider CTQ2016-81797-REDC), the Gobierno deAragón (E35), Fondo Europeo de Desarrollo Regional (FEDER), and the European Social Fund (FSE) is acknowledged.

Communication.-- Titulo del pdf: Making Easier the β-Lactam Fragmentation via Metal-Assistance: Mechanistic Insight., The mechanism of OsH6(PiPr3)2-mediated fragmentation of a 4-(2 pyridyl)-2-azetidinone has been investigated by DFT calculations. The addition of the C4-H bond of the substrate to OsH2(PiPr3)2 allows the active participation of an osmium lone pair in the B-type b-lactam fragmentation process. This new mechanism makes the N1-C4/C2-C3 fragmentation of the lactamic core thermally accessible through a stepwise process., Financial support from the Spanish MINECO and FEDER (Projects CTQ2013-46459-C2-01-P, CTQ2014-52799-P, CTQ2014-54071-P, and CTQ2014-51912-REDC), the DGA (E35), and the European Social Fund (FSE) is acknowledged