Synthesis And Application Of Ruthenium Complex-Based Luminescence Probes

Due to the importance of the bio-active species, such as reactive oxygen/nitrogen species and amino acids, the development of analytical techniques to detect and characterize these species has become an active area in recent years. Among various detection techniques, the luminescence (fluorescence and phosphorescence) probe technique is considered to be one of most promising methods due to its simplicity, high sensitivity and selectivity, and utility to combine with microscopy imaging for real-time and in-situ intracellular detection of biospecies in living biosamples, which allows the technique to be widely used in the field of biomedicine and life science. In this doctoral dissertation, several kinds of ruthenium(Ⅱ) complex-based luminescence probes for bio-active species were successfully designed and synthesized by the modification of the ligand with some reactive moieties.A unique ruthenium(Ⅱ) complex,[(Ru(bpy)2(dabpy)](PF6)2, was designed and synthesized as a highly sensitive and selective luminescence probe for nitric oxide (NO). The complex can specifically react with NO in aqueous media under the aerobic condition to yield its triazole derivative with a high reaction rate constant, accompanied by the remarkable increase of luminescence quantum yield. Compared to organic probes, the new Ru(Ⅱ) complex probe shows the advantages of large Stokes shift, good water solubility and a wide pH available range. The probe was successfully used for the luminescence imaging detections of the exogenous NO in mouse macrophage cells and endogenous NO in gardenia cells. The results demonstrated the efficacy and advantages of the new probe for the NO detection in living cells.A heterobimetallic ruthenium(Ⅱ)-copper(Ⅱ) complex-based luminescent probe,[Ru(bpy)2(bpy-DPA)Cu](PF6)4, was designed and synthesized for the highly selective and sensitive detection of sulfide anions in aqueous media. Owing to the high affinity of sulfide to Cu(Ⅱ). the non-luminescent probe can specifically and rapidly react with sulfide to yield the corresponding ruthenium(Ⅱ) complex.[Ru(bpy)2(bpy-DPA)]2+, accompanied by the remarkable luminescence enhancement. Based on this probe, a rapid, selective and sensitive luminescence method for the detection of sulfide anions in wastewater samples was established.A series of ruthenium(Ⅱ) complexes based luminescence probes.[Ru(CHO-bpy)3](PF6)2,[Ru(bpy)2(DNBSO-bpy)](PF6)2and [Ru(bpy)3-n(DNP-bpy)n](PF6)2(n=1,2,3), were designed and synthesized for the highly selective and sensitive detections of mercapto-biomolecules. The almost non-luminescent probe,[Ru(CHO-bpy)3](PF6)2. can rapidly react with Cys and Hcy to yield the corresponding thiazolidine and thiazinane derivatives, accompanied by the remarkable luminescence enhancement and a large blue-shift of the maximum emission wavelength. Although this probe has the advantages of short response time, a remarkable change of the maximum emission wavelength, and high selectivity and sensitivity, the use of water-organic solvent of the probe limited its further application to bioassays. Compared to [Ru(CHO-bpy)3](PF6)2,[Ru(bpy)2(DNBSO·bpy)](PF6)2can be used for the detection of bio-thiols in aqueous media. The luminescence of [Ru(bpy)2(DNBSO-bpy)](PF6)2is quenched by the DNBSO moiety-induced photoinduced electron transfer (PET) process. Cleavage of DNBSO by bio-thiols to form [Ru(bpy)2(HP-bpy)](PF6)2will re-store the luminescence of Ru(II) complex. The advantages of the probe including short response time, high selectivity and sensitivity, and good water solubility enabled it to be used for the luminescence imaging of bio-thiols in living HeLa cells. For highly selective and sensitive detection of thiophenol in aqueous media, a systematic series of Ru(Ⅱ)-bipyrindine complex derivatives,[Ru(bpy)3-n(DNP-bpy)n](PF6)2(n=1,2.3), were designed and synthesized. The specific reaction between the probes and thiophenol triggers the cleavage of2,4-dinitrophenyl, to form [Ru(bpy)3-n(HP-bpy)n](PF6)2(n=1,2,3), resulting in elimination of the PET effect, so that the luminescence of complexes are switched on. It was found that the complex [Ru(bpy)(DNP-bpy)2](PF6)2with the most asymmetric structure, showed almost as twice as high luminescence on-to-off contrast ratio compared to the other two. This complex was successfully used as a cell-membrane permeable probe for the quantitative luminescence imaging of dynamic intracellular process of thiophenol in living cells.A novel Ru(II) complex-based luminescent probe for hypochlorite.[Ru(bpy)2(AN-bpy)](PF6)2, was designed and synthesized for the highly sensitive and selective luminescence detection of hypochlorite. The almost non-luminescent probe can specifically and rapidly react with hypochlorite in aqueous media to yield its decomposition derivative.[Ru(bpy)2(HM-bpy)](PF6)2, to provide a remarkably enhanced luminescence signal. Using this probe, the intracellular hypochlorite generation was clearly imaged via the red luminescence signal. The advantages of high specificity, sensitivity, very low background, water solubility, kinetic and thermodynamic stabilities, operation in a wide pH range, and facile synthesis ensure that [Ru(bpy)2(AN-bpy)](PF6)2will be a highly valuable probe for detecting hypochlorite in complicated biological systems.