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Synthesis And Properties Investigation Of Iridium(?) Complex-based Fluorescent Probe With Larger Stokes Shift

Posted on:2022-08-26Degree:MasterType:Thesis
Country:ChinaCandidate:L XiaoFull Text:PDF
GTID:2481306524960309Subject:Inorganic Chemistry
Abstract/Summary:PDF Full Text Request
Transition metal complexes have been widely used in various fields due to their excellent photophysical and photochemical properties,such as organic electroluminescent devices,electrochemical sensing,biological imaging,fluorescence detection and so on.Many fluorescent probes based on organic small molecules have been reported in fluorescence detection.Meanwhile,iridium complexes based probes have attracted people's attention due to their excellent photophysical and photochemical properties.Iridium complexes have a larger Stokes shift than other organic small molecules,which can reduce the overlap between the absorption spectrum and the emission spectrum.It is conducive for the probe to use in vivo and cell imaging.In addition,by simply adjusting the ligand,iridium complex can realize the color change from visible region to near-infrared region,and simple modification of ligand can realize the multi-function of probe.At the same time,iridium complexes also have the characteristics of long lifetime.These characteristics indicate that the application of iridium complexes as fluorescent probes will have far-reaching significance for the development of fluorescence detection.Combined with the development status of iridium complex fluorescent probes,using a metal iridium complex as a fluorophore,attached to different recognition groups,three new iridium complex-based fluorescent probes with larger Stokes shift were designed and synthesized.Their spectral properties toward analytes(Hg2+,thiophenol,HOCl)had been systematically investigated,such as recognition mechanism and its application in water samples and cells.1.Ir-BMZ,a fluorescent probe of near infrared iridium complex modified by benzimidazole,was synthesized by designing N^N ligand.Hg2+was complexed with N atom of imidazole group to quench the fluorescence instantaneously.The probe Ir-BMZ showed good selectivity and sensitivity for the detection of Hg2+.Through the detection of actual water samples,it is proved that the probe can be used for the detection of Hg2+in water samples.2.A fluorescent probe Ir-DNBS with 2,4-dinitrobenzenesulfonyl chloride as phenylthiophenol recognition group and iridium complex as fluorophore was designed and synthesized.The fluorescence of Ir-1 is completely quenched due to the strong electron absorption of the recognition group.The results of mechanism study showed that the aromatic nucleophilic substitution reaction between thiophene and probe Ir-DNBS occurred,and the recognition group could be removed within 9minutes to achieve the effect of complete recovery of fluorescence.The results of spectroscopic experiments show that Ir-DNBS has a large Stokes shift(200 nm)and a long fluorescence lifetime(135 ns).It has high sensitivity(62.5 n M)and high selectivity for the detection of thiophene,and has the potential to be used for the quantitative detection of thiophene in real water samples and human serum.3.A green iridium complex fluorescent probe Ir-PFBS,containing pentafluorobenzenesulfonyl group,was synthesized and its photophysical and photochemical properties were tested.The probe Ir-PFBS has excellent water solubility and can be used to detect HOCl in pure PBS solution.The fluorescence of probe Ir-PFBS is quenched in the process of HOCl recognition.The probe Ir-PFBS not only can specifically respond to HOCl,but also can realize the quantitative detection of p H in weak acid environment(p H=4-7).The fluorescence conversion in different acid-base environment has good reversibility.The probe Ir-PFBS also has a large Stokes shift(200 nm)and a long fluorescence lifetime(202.68 ns).In practical application,because of its good water solubility and low cytotoxicity,probe Ir-PFBS can be used for lysosomal localization,and can also be used to detect HOCl in water samples and living cells.
Keywords/Search Tags:Stokes shift, iridium complex, fluorescent probe, water sample detection
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