| The optical chemosensor was a kind of molecular device indicating recognition information of objective molecular through outputting optical signal, which was widely applied in the fields of biomedical, environmental detection and chemical analysis. The synthesis and propertical study of optical chemosensors remained studied focus in the field of supramolecular chemistry in twenty-first Century. The design and synthesis of excellent performance optical chemosensor was whether to choose the appropriate sensor connector, photosensitive groups and acceptor, the azacrown ether was ideal sensor recipient owing to having good selectivly complexation property with metal ions. If the azacrown ether was equipped with the appropriate photosensitive group, which was attached to the crown ether ring by the appropriate linker, it was expected to prepare a good sensing performance photochemical sensor.Hydrazone functional group is characterized by-CH=N-NH- or-CO-NH-N=CH- structure, that enables it can be effectively bonded with the metal ions, while having a spectral activity. 8-hydroxy quinoline derivatives were good photosensitive groups and they had a strong chelating effect to certain metal ions. Therefore, in this paper, it is so far rare that quinoline groups were attached to azacrown ether ring through a hydrazone chain to get some sensor moleculars of armed quinoline hydrazone azacrown ether, and their structure and the mechanism of metal ions’ selectivity sensing were detail studied.N-(8-hydroxyquinoline-5-carboxaldehydeacetylhydrazone)-benzoaza-15-crown-5(L1), N-(8-hydroxy-quinoline-2-carboxaldehyde acetylhydrazone)-benzoaza-15-crown-5(L2) and 8-hydroxy-2-quinolinecarbaldehyde-4-nitrophenyl hydrazone(L3) fragment molecule, three compounds were designed and synthesized. They were characterized by melting point,determination, 1HNMR, elemental analysis and mass spectrometry. We investigated their selectively recognition and sensing mechanism with metal ions by UV-vis and fluorescence spectroscopy methods. Specific studies are as follows:1. In the second chapter, N-(8-hydroxyquinoline-5-carboxaldehyde acetylhydrazone) benzoaza-15-crown-5(L1) was synthesized, and its recognition on 13 kinds of metal ions(Li+, K+, Na+, Mg2+, Ca2+, Cd2+, Mn2+,Ni2+, Co2+, Hg2+, Al3+, Cu2+ and Zn2+) in the methanol Solution was investigated by UV-vis and fluorescence spectroscopy methods. The result indicated that the UV-vis spectrum of crown ether L1 could recognite other metal ions outside Li+, K+ and Na+, while the fluorescence spectrum of crown ether L1 behaved recognition to Mg2+, Ca2+, Cd2+, Al3+ and Zn2+, these five kinds of metal ions can be effectively enhanced the fluorescence of crown ether L1. Because of the crown ether L1 was bonding with metal ions, which inhibited photoinduced electron transfer intramolecular process(PET). The spectrophotometric titration indicated that the 1:1 binding stoichiometry of crown ether L1 with Mg2+, Ca2+, Cd2+, Al3+, Zn2+, Mn2+ and Ni2+ respetively.2. In order to investigate the impact of the change in the connected position of photosensitive groups on recognition properties of the overall sensor molecule,in the third chapter, N-(8-hydroxyquinoline-2-carboxaldehyde acetylhydrazone) benzoaza-15-crown-5(L2) was synthesized, and its recognition property on 13 kinds of metal ions in the methanol solution was investigated by UV-vis and fluorescence spectroscopy methods. The result indicated that the UV-vis spectrum of crown ether L2 could recognite other metal ions outside Li+, K+, Na+ and Mg2+; however, the fluorescence spectrum of it behaved recoginition and sensing behavior to Al3+, and the spectral properties of the crown ether L2 is greately different from crown ether L1,possibly because of changes in the position of photosensitive groups connected, causing crown ether molecules π-π conjugated different effects.The spectrophotometric titration indicated that the 1:1 binding stoichiometry of crown ether L1 with Ca2+, Cd2+, Al3+, Zn2+, Cu2+, Co2+, Hg2+, Mn2+ and Ni2+respetively.3. In order to study the impact of the connection system and signal system of the sensor molecule in its selectively recognition on metal ions, in the fourth chapter, 8-hydroxy-2-quinolinecarbaldehyde-4-nitrophenyl hydrazone(L3)fragment molecule was synthesized, and the recognition influence of 11 kinds of metal ions(Li+, K+, Mg2+, Ca2+, Mn2+, Co2+, Ni2+, Zn2+, Cd2+, Hg2+ and Cu2+)on the spectra of phenylhydrazone L3 were investigated by the UV-Vis spectrum method in DMSO-methanol(V/V=1/9) mixed solvent. The result indicated that the UV-Vis spectra of phenylhydrazone L3 only behaved special recognition and sensitivity to Cu2+ and Zn2+. Phenylhydrazone L3 was transformed from yellow into orange or dark red upon adding Cu2+ or Zn2+respectively, which decreased in the absorption at 413 nm and generated the new absorption near 485 nm and 508 nm. Competition experiments indicate that other cations but Cu2+ have no effect on the detection of Zn2+, while the presence of other ions had no effect to the detection of Cu2+. The spectrophotometric titration indicated that phenylhydrazone L3 to Cu2+ and Zn2+ with 1: 1 and 1: 2 binding stoichiometry respectively. In conclusion, the spectra study result of crown ethers L1, L2 and L3 found that the ability of selectively recognition of crown ether L1 and crown ether L2 on metal ions was relatively poor, while quinoline phenylhydrazone L3 showed good selectivity recognition on metal ions. |
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