Fluorescent Molecular Probes Based On Tunable PET Mechanism For Metal Ions Detection

With the speeding up of industrialization process, the metal mine suffered fromexcavation, refine and so on. A large number of heavy metals accessing to the soil and waterhave been causing environmental pollution. Different concentrations of heavy metal ions arebenefit or harmful to some degree for environment and human. Therefore, the detection ofmetal ions is of great significance. Several conventional analytical methods for metal ionsdetection, such as atomic absorption/emission spectrophotometry, and ion-coupled plasmaemission-mass spectrometry are not only expensive and time-consuming in practice, but alsorequirement of highly trained individuals. Comparatively, fluorescence methods show uniquepotential for sensitivity and selectivity for metal ions with relatively simple analysis protocolsand have afforded essential basis in chemistry and biomedical systems. Also provide a newguiding ideology for detection of heavy metal ions.In this thesis, a series of fluorescent probes (FC1, FC2, YQ1, YQ5, LS1, LS2) havebeen synthesized. Their structures were characterized by1H NMR,13C NMR, ESI-HRMS,and elemental analysis. And then, we explored the optical properties of molecular probes byUV-Vis and fluorescence spectra. The research results are listed as follows:The fluorescent probes FC1and FC2demonstrated unique ability to discriminatebetween Hg2+and chemically close ions and formed the1:1stoichiometry of L-Hg2+(L=FC1, FC2) complexes. In ethanol/water (1:1, v/v), the detection limits of the probes FC1and FC2towards Hg2+ions down to the1.00×10-7M、7.96×10-8M, respectively, areobtained. Upon FC2intercalation in DNA, however, the PET process became much moreefficient. The resulted intercalates showed a high selectivity and sensitivity for Ag+withexcellent fluorescence turn-on effect. The detection limit is8.0810-9M.Benzothiazole derivatives named YQ1and YQ5have been successfully synthesized.The chemosensors present good performance in long-wavelength region, which is expected tohave potential as optical sensors for protons and metal ions. YQ5could be used as an efficientCu2+-selective colorimetric chemosensor in aqueous acetonitrile solution. Furtherinvestigations showed that the detection limit of YQ5was estimated to be2.77×10-8M.For further given the importance of S, Se in new probe design, rhodamine B derivativesLS1, LS2with S or Se donors as ion-binding sites have been synthesized. They could detectpalladium ion with excellent selectivity in water solution.In content, through a system research, a series of fluorescent probes based on the dyes ofquinolizinium, benzothiazole and rhodamine B as optical signal-reporting groups have beendeveloped. Their molecular recognition behaviors have been investigated detailly.