Four new binuclear platinum (II) complexes with 2-(1H)-quinolinone as bridging ligands: Synthesis, crystal structure and photophysical properties

Four new binuclear platinum (II) complexes were successfully synthesized named [Pt(bzq)(μ-C9H7NO)]2 (1), [Pt(dpp)(μ-C9H7NO)]2 (2), [Pt(dpq)(μ-C9H7NO)]2 (3), [Pt(ppy)(μ-C9H7NO)]2 (4), where 7,8-benzoquinoline (hbzq), 2,3-diphenylpyrazine (hdpp), 2,3-diphenylquinoxaline (hdpq) and 2-phenylpyridine (hppy), were used as cyclometalated ligands and 2-(1H)-quinolinone (μ-C9H8NO) firstly served as a bridging ligand, respectively. Their crystal structure, photophysical and time-dependent density functional theory calculations characteristics were investigated. The X-ray structure for four compounds showed that Pt(II)-Pt(II) distances were 2.8485 Å, 2.8325 Å, 2.8833 Å, 2.8707 Å respectively, which testified absorption and emission of the complexes benefited from metal-metal-to-ligand charge transfer (MMLCT) transitions. A near-infrared emissive peak of 2 is 762 nm in the neat film.