Designing And Synthesizing Optical Molecule Probe And The Studying Of Its Capability For Cation Recognition

Photochemical probes were rapidly applied in ion recognition due to its high sensitivity, easy detection and living imaging analysis. Because of the important roles of copper ions and potassium ion in environmental and life science, designing and synthesizing probes with high selectivity and sensitivity for them is still a quite active research field in chemistry.4-Phenylsemicarbazide was a good ligand for metal ions, it can occur coordination effect with a variety of metal ions. According to the different light emitting mechanism 4-phenylsemicarbazide derivatives can recognize metal ions. Therefore, we successfully synthesized a series of 4-phenylsemicarbazide derivatives as photochemical probes. At the same time, we studied their capability for cation recognition and discussed the mechanism of cation recognition in this thesis, which includes three chapters. The mam contents and results are outlined as follows:Chapter 1 briefly summaried the factors of the enhancement of resonance Rayleigh scattering(RRS) intensity and the mechanism of fluorescent recognition. And briefly summaried the research progresses in the photochemical probes for cation, which were introduced by the change of probe structure. The research content and significance are proposed in this paper. Research ideas of the thesis were also presented.Chapter 2 efficient photochemical probe 4-phenylsemicarbazide derivatives were synthesized as a selective Resonance rayleigh scattering probe for copper(II) ion. PHC showed a remarkable resonance rayleigh scattering enhancement to Cu2+, exhibited high selectivity for Cu2+. The probe could be used in naked eye detection with distinct color changing from colorless to yellow.Chapter 34-phenylsemicarbazide derivative were synthesized as a selective fluorescent receptor for potassium ion with high selectivity and sensitivity. And the chemosensor was successfully employed to determinate K+ in human serum samples.N-phenyl-2-(pyridin-2-ylmethylene)hydrazinecarboxamide(probe PHC) was examined as probe for metal ions. It was found that, in ACN, only Cu2+ induced remarkable enhancement in the resonance rayleigh scattering of PHC, by an enhancement of up to 50 folds. In order to understand the banding mode between PHC and Cu2+. A 1:2 stoichiometry of Cu2+ binding to PHC was made evident from Job plot. Thus, we could deduce that one Cu2+was suitably at the coordination center of two receptor molecules via its carbonyl O, imino N and pyridine N atoms. RRS spectrum of the binding product was located at its molecular absorption band. The 294 nm scattering peak of the complex was good corresponding to its absorption peak 295 nm, so the scattering could resonates with the light absorption to produce a Resonance Rayleigh Scattering, which enhanced the scattering intensity. After receptor molecules with Cu2+ formed a stable combination the rotation of benzene ring was limited and the C=N isomerization was inhibited, which also increased the molecular plane rigidity. Meanwhile, increasing of the volume of the binding product also enhanced the scattering intensity. Thus, it was because of the above reasons that the RRS intensity of probe PHC increased noticeably. Then PHC was examined as a probe for Cu2+ acetonitrile-water binary solvents. The research showed only Cu2+could induce fluorescence enhancement of probe PHC in 10% H2O- ACN(V/V) mixture, which other metal ions have no effect.Ini order to further study its practical significance, the proposed method was applied satisfactorily to detect Cu2+ concentration in wastewater and drinking water samples.The results were consistent with those by the developed method AAS method, which would provide valuable evidence for environmental testing personnel to use the receptor PHC reasonably. The probe could be used in naked eye detection with distinct color changing from colorless to yellow. Because of that, We prepared the copper ion qualitative test paper, only Cu2+ could induce color change of the copper ion qualitative test paper, which other metal ions have on effect. The result was also satisfactory.Hydrazinecarboxamide, N-phenyl-2-[(phenylamino)thioxomethyl (HPPT) was examined as probe for metal ions. It was found that, in ACN, only K+ induces remarkable enhancement in the fluorescence of HPPT, by an enhancement of up to 10 folds. In order to understand the banding mode between HPPT and K+. The fluorescence spectra of HPPT in different polar solvents were also recorded. It was revealed that the fluorescent emission band showed no dependence on polarity of solvents and protic solvents, although the fluorescence spectra of HPPT in different solvents were affected. We found the 1H NMR spectras of HPPT and HPPT-K+ are the same. The result indicated that HPPT did not form coordinate bond with K+ that was consistent with the above phenomenon of absorption spectrum but form certain weak interaction between HPPT and K+, which need further study and analysis. We still got a preliminary conclusion that K+ fluorescent receptor was mainly based on fluorescence signaling mechanism of photoinduced electron transfer (PET). When adding to K+, process of photoinduced electron transfer (PET) of HPPT was suppressed, which was primary cause of the fluorescence enhancement.We used fluorescence spectroscopy, absorption spectroscopy, resonance rayleigh scattering spectroscopy, mass spectrometry and NMR to study the molecule characters and recognized mechanisms. The study here provides a new strategy for constructing and optimizing cation photochemical probes.