A series of square-planar Pt(II) complexes [Pt(C^N)(O^O)] (1â5) (C^N = 2-phenylpyridine, O^O denotes a series of β-diketonate ligands) is reported. Detailed studies of theoretical calculations, electrochemical and photophysical properties have shown that their excited states can be attributed to the mixing of 3MLCT, 3LLCT and 3LC/3ILCT transitions. For 1, the excited state is dominated by the C^N ligand. The excited states of complexes 2â5, however, are dominated by O^O ligands. Through variation of the β-diketonate ligands, the emission colors of 1â5 can be tuned from blue-green to yellow. Further investigations have revealed that the emission of 4 in the solid state can be attributed to the 3MLCT and 3LLL'CT transitions, which has been confirmed by X-ray diffraction studies as well as theoretical calculations. Moreover, exclusive staining of cytoplasm and low cytotoxicity have been observed for 1â4, which makes them promising candidates as phosphorescent probes for bioimaging.
报道了一系列平面方形的Pt(II)复合物[Pt(C^N)(O^O)] (1–5)(C^N =
2-苯基吡啶,O^O表示一系列
β-二酮配体)。详细的理论计算、电
化学和光物理特性研究表明,它们的激发态可以归因于3MLCT、3LLCT和3LC/3ILCT跃迁的混合。对于化合物1,激发态主要由C^N
配体主导。然而,化合物2–5的激发态则主要由O^O
配体主导。通过改变
β-二酮配体,可以调节1–5的发射颜色,从蓝绿色到黄色。进一步的研究表明,化合物4在固态下的发射可以归因于3MLCT和3LLL'CT跃迁,这已通过X射线衍射研究和理论计算得到了确认。此外,1–4在细胞质中独占性染色且具有低细胞毒性,这使得它们成为
生物成像的有前景的
磷光探针候选物。