The Synthesis And Properties Of Naphthyridine-derived And Quinoline-derived Rhodamine Chemosensors

As is known to all, the fluorescent chemosensors, relative to other analysismethods, have the advantages of high selectivity, high sensitivity, low detection limit,and on-site monitoring quickly and timely, therefore the development of them hasbeen receiving considable attention in medical, environmental and biological fields.Because of its high molar extinction coefficient, high quantity yield and to beexcitable at long wavelengths, rhodamine B and its derivatives are widely used invarious fields. Therefore, the introduction of spiroring-opening of rhodamine B andits derivatives to construct probes has provided a new direction for the design ofnovel chemosensors. In this thesis, with rhodamine B, hydrazine hydrate,1,8-naphthyridine derivatives and quinoline aldehyde as the raw materials, two kindsof chemical sensors A and B which can response to certain metal ions are designedand synthesized. The concrete content is as follows:1. With1,8-naphthyridine derivatives and quinoline aldehyde as the rawmaterials, we have designed and synthesized two compounds A and B. Then througha series of characterization means, such as infrared spectrometer (IR), high-resolutionmass spectrometry (HRMS), nuclear magnetic resonance (NMR) and so on, theirstructures were confirmed.2. The spectral properties of two chemical sensors A and B, which are analyzedby means of UV-vis spectrophotometer and fluorescence spectrophotometer, are asfollows: By using the properties of spiroring-opening of rhodamine derivatives, thecompound A can identify Al3+through taking advantage of the fluorescence behaviorin ethanol solution, and detect Cu2+by adopting the colorimetric method in aqueoussolution; at the same time, the compound B in ethanol solution can detect Al3+with adual-model, namely both of fluorescence and colorimetric methods. In addition, twochemical sensors both have high fluorescence quantum yield and display a goodselectivity for Al3+/Cu2+among environmentally and biologically relevant metal ions.3. Along with the addition of F/EDTA into the solution of compound A and B which have been joined Al3+/Cu2+respectively, the absorption and fluorescencesignals identical to those of A and B can be restored, demonstrating that the bindingof chemosensors A and B to Al3+/Cu2+is really chemically reversible.4. Job’s plots and a time-of-flight mass spectral study indicated that eachchemosensor chelated Al3+with1:1stoichiometry.5. The mechanism of absorption and fluorescence change which results in thenew absorption and emission peaks can be ascribed to the rhodamine ring-openingprocess. The different selectivity of these chemosensors in different solvents may beascribed to the different binding ability of chemosensors/water towards Al3+and Cu2+.