Synthesis And Fluorescent Sensing Properties Of Functionalized Metal-Organic Complexes

Functional metal-organic complexes present remarkable luminescence performances because they have both inorganic and organic luminescence platforms.The addition of external substances or internal structural variations can contribute to fluorescent changes of the complexes.As fluorescent sensors,functional metal-organic complexes show the features of high sensitivity,good selectivity,low detection limit,and short response time.Therefore,functional metal-organic complexes are widely used in the fluorescent identification of different substances.In this thesis,three functional metal-organic complexes,CD-MONT-2',MOF-74-Mg,and UPC-22 are used as the molecular fluorescent probers for the identification of hydrogen sulfide,uric acid,metallic silver ions,and aromatic nitro compounds,respectively.The sensing mechanisms are investigated by using fluorescent spectra,X-ray powder diffraction,FTIR,UV-Vis,¹HNMR,X-ray photoelectron spectroscopy,density functional theory calculations,and HPLC.Moreover,the probes are successfully applied in the areas of cell imaging and visual recognition.The main contents of this thesis are shown as follows:1.The CD-MONT-2'is used as a fluorescent turn-on sensor for H₂S detection with high selectivity and moderate sensitivity in a solution state.The mechanism is based on the coordination of H₂S to the central metal ions of the probe to change the fluorescence intensity.Moreover,the CD-MONT-2'is successfully applied in the field of live-cell imaging in Hela cells by identifying the hydrogen sulfide sources in the cells.Our study gives a new sight for the design and synthesis of metal-organic complexes fluorescent probes.2.The CD-MONT-2'is used as a fluorescent turn-on sensor for uric acid detection with high selectivity and sensitivity with the detection limit of 4.3?M in a suspension state.The sensing mechanism arises from the host–guest interaction of uric acid with the capsule-like CD-MONT-2'and is quite different from the previous reports.The CD-MONT-2'is also successfully applied in the removal of uric acid in aqueous solution.Our study gives a new insight for the design of new fluorescent probes for uric acid recognition.3.The CD-MONT-2'is synthesized by a modified biphasic liquid-solid-liquid?BLSL?strategy,and used as a fluorescent turn-off sensor for H₂S detection with good selectivity and sensitivity in a suspension state.The sensing mechanism arises from the decomposition of CD-MONT-2'into fluorescent silence species.Moreover,visualized H₂S test papers was prepared by mixing the suspension of CD-MONT-2'with the water solution of sodium carboxyl methyl cellulose.Compared with lead acetate papers,the CD-MONT-2'visual test papers can be used directly and shows higher stability and sensitivity.These results suggest that the CD-MONT-2'has potential application for H₂S detection.4.The CD-MONT-2'is used as a fluorescent turn-off sensor for Ag⁺detection with good selectivity in a suspension state.The sensing mechanism arises from that Ag⁺brings about the aggregation of fluorescent molecular,leading to the competition of absorption of light.Energy converts to molecular vibration or other form rather than exited photons.5.The CD-MONT-2',MOF-74-Mg and UPC-22 are synthesized and utilized as fluorescent turn-off sensors for 2,4,6-trinitrophenol detection.All of them present good selectivity and sensitivity in a suspension state.The sensing mechanisms arise from the interaction between metal-organic complexes and electron-withdrawing group of-NO₂.Our study gives an insight for the design of new fluorescent probes for nitro compounds recognition.