Synthesis And Application Of Ruthenium Complex-Based Probes For Bioactive Species

Ruthenium???polypyridyl complexes are widely used in fluorescent probes and sensors,which stems largely from their appealing photophysical and photochemical properties,as well as good cell membrane permeability and biocompatibility.Moreover,their properties can be tuned by varying the nature and the numbers of the polypyridyl ligands around the Ru???metal centre.In this paper,three luminescent probes were synthesized through modifying bipyridine with specific recognition groups to apply in the detections of bioactive species/anion in vivo or food samples.A ruthenium???complex,Ru-NA,has been developed as a chemo sensor for the highly selective and sensitive detection of hypochlorous acid in vitro.The photoluminscent intensity of the probe is very weak because the fluorescence of ruthenium complex is quenched by the unique rotation of N-N bond in the acetohydrazide group.The cleavage of hydrazine linker by a HOCl induced specific reaction led to damge the N-N bond,accompanied by significant luminescence enhancement.Upon reaction with hypochlorous acid,an approximate 19-fold increase in PL intensity at 620 nm,and a 44-fold increase in PL intensity at 538 nm would be afforded.The dose-dependent in PL enhancement shows a good linearity for hypochlorous acid.The obtained probe has improved performance in HOCl sensing,such as fast response,good water solubility and high sensitivity.Using the probe,we have detected endogenously produced HOCl in mouse macrophages.In addition,Ru-CHO was developed for fast,highly sensitive and selective recognition and detection of hydrogen sulfite.Ru-CHO was found to be weakly luminescent due to the intramolecular charge transfer dominated by the strong electron withdrawing aldehyde groups.In the presence of hydrogen sulfite,the aldehyde groups in Ru-CHO can specifically react with hydrogen sulfite,which results in the formation of a new ruthenium???complex Ru-SO,lead to the remarkable luminescence enhancement.The results of titration analysis,kinetic experiment and selective test suggested the availability of Ru-CHO for the rapid quantification of hydrogen sulfite in aqueous media,which indicates that the present method has good precision and accuracy for the detection of hydrogen sulfite in food samples.Another based-on ruthenium probe for hydrogen peroxide was designed and has been synthesized in the last chapter.It has potential application value in real-time detection of intracellular H₂O₂ after further improvement of the complex Ru-Dione-Fc.