Iminopyridonato Iridium Complexes: Suitable FLPs for C-X Bond Activation

Abstract

A new series of 2-pyridonato-based Ir(III) half-sandwich complexes [(η5-Cp*)IrX(2-{(2,6-iPr2-C6H3)N=CH}-C5H3N-6-(O))] (3: X = Cl; 4: X = I) were prepared via a unique thermally initiated demethylation of the corresponding ionic complexes [(η5-Cp*)IrX(κ2-{2-[(2,6-iPr2-C6H3)N=CH]-6-(OMe)C5H3N})](X) (1: X = Cl; 2: X = I). The neutral complex 3 was further studied as versatile precursors for the preparation of unprecedented polymetallic Ir-Zn and Ir-Zn-Ru complexes. Furthermore, photoluminescent study of the three structural motifs: ionic, neutral and bimetallic, supported by TD-DFT calculations, revealed unusual red to near-infrared emissions in both solution and solid state. Mos importantly, neutral complex 3 with electron-rich the C=O group were capable of activating C(sp3)-X bonds, leading to the isolation of ionic Ir(III) complexes with new O-C(sp3) bonds in the ligand frame.