双磷光发射铱配合物的设计、制备、光物理性质研究及其在氧气检测中的应用

发布时间：2019-01-18 21:45

【摘要】：磷光铱配合物作为新型发光探针被广泛用于检测阴阳离子、氨基酸、核酸、生物大分子等各种分析物以及微环境pH、温度、氧气浓度等参数。当分析物浓度或环境参数发生变化时,铱配合物通过发射强度或寿命的响应,达到检测目的。大多数d6电子组态的过渡金属配合物发光激发态源于金属到配体电荷转移态(MLCT)(如Ru(II)、Os(II)等),铱(III)配合物的发射态更加多样化,除了MLCT,常见的还包括配体内以及配体间的电荷转移态(IL,LLCT)。这些发射激发态非常容易受配体结构和所处环境影响,并且在某些条件下,两种发射激发态可同时存在,使得铱配合物具有双磷光发射性质。在本论文中主要研究一类在室温下具有双磷光发射的铱配合物,并发展它们在氧气检测中的应用:1.双磷光发射铱配合物的设计、合成及光物理性质的研究我们发现了一类含有氨基修饰N^C配体的铱配合物具有双磷光发射性质,因此,设计、合成了一系列结构通式为[Ir(ppy-CH_2NR~1R~2)_2(bpy-CONH)](PF6)的铱配合物物,通过在其N^C配体中引入伯胺、仲胺、叔胺基团,详细研究它们的光物理性质,尤其是双磷光发射性质。同时,合成了不含氨基的配合物,进行对照实验。用1H NMR、质谱等方法对这些配合物的结构进行了表征。我们发现当N^C配体上引入给电子能力较强的仲胺和叔胺取代基时(配合物3、4),配合物表现出明显的双磷光发射性质。利用TD-DFT实验研究其发光机理,我们认为氨基到配体的电荷转移态(NLCT)的存在干扰了配合物IL(配体间的电荷转移态)和MLCT(金属到配体的电荷转移态)之间的内转换过程,实现了配合物的双磷光发射性质。此外,由于两个发射态的激发态寿命不同,它们对氧气猝灭的敏感度存在较大差异。因此,双磷光发射铱配合物可作为小分子磷光探针,对氧气具有磷光比率响应。2.双磷光发射铱配合物比率型氧气探针的设计、制备以及活细胞检测中的应用我们设计、合成了不含氨基、含有仲胺、叔胺的磷光铱配合物,通式为[Ir(ppy-CH_2-R)_2(bpy-(CONH-C_4H_9)_2)](PF_6)(R=H(5),NHC_4H_9(6),NC_5H_(10)(7))。用1H NMR、质谱等方法对这些配合物的结构进行了表征,并详细研究其光物理性质。实验表明,配合物7在室温下表现出双峰发射,发射峰位置分别在525 nm和630 nm。详细研究配合物7对氧气的响应,发现在不同的氧气浓度环境中,发射强度和衰减寿命都发生明显变化,而且,我们证明其响应具有良好的线性关系,且响应范围更宽,可以实现低氧和高氧含量的比率检测。同时,还发现配合物7具有良好的生物相容性和细胞摄取效率而且细胞毒性较低,因此在细胞检测中具有良好的应用前景。利用双通道共聚焦成像进行了配合物7在活细胞内氧气含量的成像实验,在氧气含量不同时,活细胞中的发光强度有明显变化,而且不仅能够实现细胞内乏氧成像,而且可以实现细胞内高氧检测。
[Abstract]:Phosphoiridium complex is widely used as a new luminescent probe to detect anion, amino acid, nucleic acid, biomolecules and microenvironment parameters such as pH, temperature, oxygen concentration and so on. The iridium complex can be detected by the response of emission intensity or lifetime when the analytical concentration or environmental parameters change. Most of the transition metal complexes with d 6 electron configurations have luminescent excited states derived from metal to ligand charge transfer states (MLCT) (, for example, Ru (II), Os (II), etc.), and iridium (III) complexes exhibit more diverse emission states, except for MLCT, Also common are the charge transfer states (IL,LLCT) in ligand and between ligands. These excited states are very easy to be affected by the structure of ligands and the environment, and under some conditions, the two excited states can exist simultaneously, which makes the iridium complexes have double phosphorescence emission properties. In this paper, a class of iridium complexes with double phosphorescence emission at room temperature are studied, and their applications in oxygen detection are developed: 1. Design, synthesis and photophysical properties of double phosphorescent iridium complexes We have found that a class of iridium complexes containing amino modified N ^ C ligands have double phosphorescence emission properties. A series of iridium complexes with a general structure of [Ir (ppy-CH_2NR~1R~2) _ 2 (bpy-CONH)] (PF6) were synthesized. Their photophysical properties were studied in detail by introducing primary, secondary and tertiary amine groups into their N ^ C ligands. In particular, the double phosphorescence emission properties. At the same time, the complexes without amino groups were synthesized and compared with each other. The structures of these complexes were characterized by 1H NMR, mass spectrometry. It is found that when the secondary amines and tertiary amines are introduced into the N ^ C ligands, the complexes exhibit obvious double phosphorescence emission properties. The luminescence mechanism was studied by TD-DFT. We believe that the existence of charge transfer state (NLCT) from amino to ligand interferes with the internal conversion process between complex IL (charge transfer state between ligands) and MLCT (charge transfer state from metal to ligand). The double phosphorescence emission properties of the complexes have been realized. In addition, the sensitivity of the two states to oxygen quenching is different due to the different lifetime of the excited states. Therefore, the double phosphorescence iridium complex can be used as a small molecular phosphorescence probe with a phosphorescence ratio of 2. 2. The Design, preparation and Application of the ratio oxygen probe of Diphosphorescent Iridium complexes We have designed and synthesized phosphoiridium complexes containing no amino, secondary amines and tertiary amines. General formula [Ir (ppy-CH_2-R) _ 2 (bpy- (CONH-C_4H_9) _ 2)] (PF_6) (RH5, NHC_4H_9 (6), NC_5H_ (10) (7).) The structures of these complexes were characterized by 1H NMR, mass spectrometry and their photophysical properties were studied in detail. The experimental results show that the complex 7 exhibits a double peak emission at room temperature, with emission peaks at 525 nm and 630 nm., respectively. The response of complex 7 to oxygen is studied in detail. It is found that the emission intensity and decay life of complex 7 vary obviously in different oxygen concentration environments. Furthermore, we prove that the response of complex 7 has a good linear relationship and a wider range of responses. The ratio of hypoxia and hyperoxia can be detected. At the same time, complex 7 has good biocompatibility, cell uptake efficiency and low cytotoxicity, so it has a good application prospect in cell detection. Two-channel confocal imaging was used to investigate the oxygen content of complex 7 in living cells. The luminescence intensity of living cells changed significantly with different oxygen content, and not only could the imaging of hypoxia in cells be realized. Moreover, it can be used to detect hyperoxia in cells.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O641.4;O657.3

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