8-Phenylquinoline-Based Tetradentate 6/6/6 Platinum(II) Complexes for Near-Infrared Emitters
Yulu Sun, Feng Zhan, Disheng Huang, Xia Wang, Lijie Dou, Kewei Xu, Yun‐Fang Yang, Guijie Li, Yuanbin She
Abstract
A series of novel tetradentate 6/6/6 Pt(II) complexes containing an 8-phenylquinoline-benzo[ d ]imidazole-carbazole ligand was designed; the Pt(II) complexes could be synthesized by metalizing the corresponding ligand with K 2 PtCl 4 in high isolated yields of 60–90%. Experimental and theoretical studies suggested that the ligand modification of the quinoline moieties of the Pt(II) complexes could tune their electrochemical, photophysical, and excited-state properties. Notably, all the Pt(II) complexes exhibited highly electrochemical stabilities with reversible redox processes except the quasi-reversible reduction of PtYL3 . The large π-conjugation of the ligand together with increased metal-to-ligand charge-transfer ( 3 MLCT) characters in T 1 states enabled the Pt(II) complexes to show broad Gaussian-type NIR emission spectra with high photoluminescence quantum efficiencies of 1.2–1.5% and short τ of 0.8–1.5 μs in dichloromethane at room temperature. This work should provide a valuable reference for the design and development of monomer NIR emitters.