The binuclear ruthenium complex [Ru2(bpy)4L](PF6)4 [Ru1(PF6)4, where L = 9,10-bis(3-(1H-imidazo[4,5-f] [1,10] phenanthrolin-2-yl)phenyl)anthracene and bpy = 2,2′-bipyridine], was designed and synthesized as pH sensing probe. The spectroscopic data displayed the anthryl-moiety characteristic absorptions at 353 nm, 373 nm and 394 nm, respectively, and MLCT absorptions at 428 nm and 457 nm. The acid–base properties of the Ru complex ion were characterized, and the ground- and excited-state acid ionization constants were derived by UV–visible absorption and emission spectra. The results showed the luminescence of Ru1 decreased obviously with the increases of pH. The electrochemical properties of Ru1 were discussed, showing one Ru (II)-centered oxidation at around 1.31 V and three ligand-centered reductions.

中文翻译：

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双核钌多吡啶配合物：合成、表征、pH 发光传感器和电化学特性

双核钌配合物 [Ru2(bpy)4L](PF6)4 [Ru1(PF6)4，其中 L = 9,10-bis(3-(1H-imidazo[4,5-f] [1,10] phenanthrolin -2-基）苯基）蒽和 bpy = 2,2'-联吡啶]，被设计和合成为 pH 传感探针。光谱数据分别显示了 353 nm、373 nm 和 394 nm 处的蒽基部分特征吸收，以及 428 nm 和 457 nm 处的 MLCT 吸收。表征了 Ru 络离子的酸碱性质，并通过紫外可见吸收和发射光谱推导出基态和激发态酸电离常数。结果表明，随着pH值的升高，Ru1的发光明显降低。讨论了 Ru1 的电化学性质，在 1.31 V 左右显示了一个以 Ru (II) 为中心的氧化和三个以配体为中心的还原。