The Synthesis And Properties Of Colorimetric Chemosensing Materials For Copper Ion And Acetate Ion

With the rapid development of global economy, our living environment has been severely destroyed. The increase of industrial pollution makes kinds of pollutants enter into the water through different ways, resulting in tremendous harm to human life. Some of these pollutants having entered waters finally exists in ionic form. Therefore, the determination of some ions for waters has important significance in the field of analytical chemistry, biochemistry, medical diagnosis and environmental monitoring.Several techniques such as spectrophotometry, absorption/emission spectroscopy and voltammetry have been used for ions assay. However, the wide utilization of these methods is largely limited due to the expensive instrumentations and complicated pretreatment procedures, not suitable for on-line or in-field monitoring of pollution waters. Owing to the advantages of simple, rapid and on-line characteristics, increasing attentions have been focused on the "naked-eye" detection technique.In this text, our purpose is to explore the synthesis of the novel and simple colorimetric chemosensor. The major achievement obtained is as follow:(1) A colorimetric and fluorescent chemosensor for Cu2+based on the mechanism of internal charge transfer (ICT) has been successfully designed and prepared by simple condensation of4-(diethylamino)salicylaldehyde and oxalyl dihydrazide. Cu2+in solution determined through dual channels:"naked-eye" observation, a visually dramatic color change from light green to orange, which could be used for qualitative determination of Cu2+; spectrofluorometry, which could quantificationally assay Cu2+. It provides a simple-to-use platform for reliable detection of Cu2+at concentrations ranging from5.0×10-7to1.1×10-5M with detection limit of1.2×10-7M, which is nearly2×102times lower than the maximum allowable level of inorganic Cu2+in drinking water (1.3ppm,-20μM) permitted by the EPA.(2) By simple condensation, a novel and simple ferrocene-based colorimetric electro-optical chemosensor for acetate ion bearing hydrazone N-H group as the binding site has been successfully prepared and spectroscopically characterized. The anion recognition via hydrogen-bonding interaction was investigated by electrochemistry and UV-vis spectroscopic measurements:the recognition process of acetate ion could be easily accompanied by a visually dramatic color change from light yellow to purple, which allowed for quick and simple "naked-eye" detection, an obvious red-shift from396nm to545nm (Δλ=149nm),and the UV-vis intensity of545nm had a good linearity (r=0.9917) with the association constant Kass=4.95×105; on stepwise addition of AcO-anion, an obvious cathodic shift of the first oxidation peak from Ep=800mV to Ep=885mV (AE=85mV) is observed, and the presence of other anions has no obvious effect on the DPV. Above two methods associated and realized dual-channel recognition with remarkable selectivity towards acetate than other anions.