Synthesis And Characterization Of Schiff Base And Secondary Amine And Study Of The Recognition With Metal Ions

Molecular recognition is an important part of supramolecular chemistry, it has a broad application and development in the field of life sciences, materials science, synthetic chemistry and information science. This work has been developped gradually in-depth, which has become a hot research topic. With industrial development and progress, the metal ion content in the atmosphere, water, soil and pollution levels is increasing. The problems of environmental pollution caused by the metal ions are more and more serious. Furthermore, metal ions also have a significant impact on human physiological function, therefore the identification and detection of the metal ion have important practical significance. There are more and more methods for detection and analysis of metal ions, like atomic absorption spectrometry, atomic emission spectrometry, plasma emission mass spectrometry and electrochemical method, but these methods have some shortcomings. Contrarily, the color chemical sensors and fluorescent chemical sensors have the superiority of high sensitivity, real-time detection, remote detection, inexpensive and easy to operate. The two methods are good for ion detection and identification and have a wide application,which provide a good conditions for the rapid development. Schiff bases compounds contain the ligand group, which have good coordination ability, can be easy to form stable metal complexes. Therefore, Schiff base is often introduced into the structure of the metal ion fluorescent sensors. At present, it has a rapid development about ion sensors based on Schiff base.This paper synthesized some intermediates of heterocyclic compounds, rhodamine6G hydrazide, isatin-based compounds. The structure of these compounds were characterized. The selected intermediate compounds in this paper have many advantages, such as the crude materials are inexpensive, synthetic route is simple, reaction conditions are mild, the yield in the whole process is high.These intermediate compounds were condensated with p-hydroxybenzaldehyde and2-hydroxyl-1-naphthaldehyde, and then the corresponding Schiff base compounds were gained. The recognition performances of these kinds of Schiff base to common metal ions were measured through the UV-visible absorption spectra and fluorescence spectrum. The analysis results showed the compound of rhodamine6G hydrazide shrink condensating with2-hydroxyl-l-naphthaldehyde(L) has a very good recognition effect on Cu2+, which owned high selectivity. The color of the solution was markedly changed from colorless to pink after Cu2+was added. Besieds, job curve research showed that the combination ratio of the Cu2+with compound is1:1. A good chemical sensor for color recognition to copper ion was got.The isatin Schiff base HN was reduced by sodium borohydride reagent, a kind of secondary amine compound HNHI was gained. We studied the recognition performance of HNHI compound to different metal ions. The results showed that compound HNHL had very good recognition effect on Cu2+, Co2+and Ni2+. UV-vis spectrum in the visible region had a new peak. Moreover, the color of the solution was changed from colorless to pink, and the fluorescence intensity was obvious enhanced. The compound could be used as a kind of recognition sensor for these three ions. Job curve research showed that the combination ratio of the metal ions to the compound HNHI is1:2.