在分子开关和生物无机化学等领域，钌(II)配合物因其优秀的光物理、光化学和生物活性而受到大量研究者的关注。目前大多数钌配合物在可见区发光，应用受到较大的限制。而近红外(NIR)发光具有高信号，对生物组织穿透能力强、损害小的优点，所以近红外发光的钌配合物应用于生物成像已成为研究热点。本论文包含近红外发光的双核钌(II)配合物的设计与合成、酸碱性质、pH对其DNA键合性质和单线态氧性质的影响，以及在HeLa细胞中pH传感的应用研究，主要工作及创新点如下：

(1)    应用单核钌配合物[(bpy)₂Ru(HL¹)](ClO₄)₂  (Ru1)为前体，合成了1个双核钌(II)配合物[(bpy)₂Ru(HL¹)Ru(H₂L²)](ClO₄)₄ (Ru2) {bpy = 2,2'联吡啶；H₂L² = 2,6-二-1H-咪唑-2-吡啶； HL₁ = 2-(2,6-二(2-吡啶基)-4-吡啶基)-1H-咪唑[4,5-f][1,10]邻菲咯啉}，通过质谱、核磁共振氢谱、元素分析、紫外-可见吸收光谱和磷光光谱对Ru2进行表征，发现其在水溶液中的近红外区发光性质。

(2)    研究了Ru2在Britton-Robinson缓冲体系中的酸碱性质。结果表明在酸性pH区发光强度最大，碱性pH区磷光发光强度较小，并且在pH = 4.0-7.0期间保持不变。同时，配合物在pH = 5.0 时产生单线态氧量子产率可达40%，在碱性区降低到1%。配合物Ru2细胞毒性较低，通过激光共聚焦显微镜成像发现配合物可以选择性地识别HeLa细胞中的溶酶体，并成功地探测HeLa细胞内pH变化，为靶向定位肿瘤细胞和正常细胞提供了理论基础。

(3)    研究了Ru2在三个不同pH下的DNA键合性质，通过紫外-可见吸收光谱和光致发光光谱滴定、溴化乙锭竞争、粘度等实验，证明配合物与DNA是以嵌入方式键合，键合能力较强，且在酸性、中性、碱性条件下与DNA键合时均呈现较强的发光，有作为生物体内核酸染色试剂的潜力。

Ruthenium(II) complexes have been widely studied as molecular switches and bioinorganic materials due to their excellent photophysical, photochemical and biological activities. The near-IR photoluminescence has become a research hotspot in biological imaging with the advantages of low background signals, strong penetration ability and small damage to the biological tissues. This thesis is devoted to the synthesis and characterization of a binuclear ruthenium(II) complex with near-infrared luminescence, acid base properties, pH effects on DNA properties, and pH switchable singlet oxygen generation properties, as well as its application in pH sensing in HeLa cells. The main contents of this thesis are as follows:

(1) A new ruthenium(II) complex of [(bpy)₂Ru(HL¹)Ru(H₂L²)](ClO₄)₄ (Ru2) {bpy = 2,2’-bipyridine, H₂L² = 2,6-di-1H-imidazole-2-pyridine, HL¹ = 2 - (2,6-bis (2-pyridyl)-4-pyridyl)-1H imidazole[4,5-f][1,10]phenanthroline} was synthesized by using mononuclear [[(bpy)₂Ru(HL¹))](ClO₄)₂  (Ru1) as precursor, and characterized by mass spectrometry, ¹H NMR, elemental analysis, UV-vis absorption and luminescence spectrodcopy.

(2) The acid-base properties of Ru2 in Britton-Robinson buffer were studied. The results show that the intensity of luminescence is the highest in the acid region, and it decreases gradually when solution pH was increased to the alkaline region. At the same time, the quantum yield of singlet oxygen generation could also be switched from 1% at a basic solution (pH = 10.0) to 40% at a acidic pH (pH = 5.0). It was found that Ru2 could selectively stain lysosomes in HeLa cells and successfully detect pH changes in HeLa cells, which can be used to differentiate tumor cells from normal cells.

(3) The ct-DNA binding properties of ruthenium complex Ru2 were studied by UV-visible absorption，emission spectra titrations and DNA competitive binding in different pH buffer solutions. It was proved that the complex exhibited pH-dependent DNA binding affinities, but remaining strong affinities from acidic to basic solutions, most probably in intercalative binding mode.