The Design, Synthesis And Ion Recognition Properties Of Several Fluorescent Molecular Probes

Because of the advantages of fast response, high sensitivity and selectivity, low detection limit, easy operation, etc, fluorescent molecular probes are widely applied in the detection of various transition metal and heavy metal ions. In this thesis, through condensation and Diels-Alder reactions, a series of new fluorescent probes were synthesized and investigated for their applications in the detection of transition metal ions(Zn2+, Fe3+) and heavy metal (Cu2+), which possess 1,8-naphyridine/aromatic compound as fluorophore, nitrogen atom as complexation atom. Some interesting results are as follows:1. A 1,8-naphthyridine-based fluorescent probe for zinc ion not only exhibits a large increase of emission intensity in ethanol, but selectively detects zinc ions in the presence of competing metal ions; moreover, cell experiment show that the aimed product can detect intracellular Zn2+.2. A fluorescent probe C was designed and synthesized as an "off-on" Zn2+ and"on-off"Cu2+ sensor, and the fluorescence signals can be restored by the addition of ethylenediaminetetraacetic acid (EDTA) disodium solution into ZnC and CuC solutions. moreover, the fluorescence emission signal of ZnC decreased with the addition of Cu2+, indicating that ZnC could detect Cu2+ via metal displacement.3. A highly selective and sensitive polyphenyl fluorescent probe A for Fe3+ and Cu2+ was synthesized. It not only exhibits a great increase of emission intensity with a large red-shift of emission peak upon addition of Fe3+, but also exhibits a great decrease of emission intensity upon addition of Cu2+ in ethanol against environmental and biological samples.4. Three fluorescent probes which show excellent selectivity towards Fe3+ are synthesized. Upon addition of FeCl3 into each of their ethanol solution, they exhibit a great decrease (for compounds B and D)or increase (for compound E) of emission intensity against environmental and biological samples. Further experiments demonstrate that Fe(NO3)3 has the similar influence as FeCl3 while Fe2(SO4)3 has no influence on that of those fluorescent probes.