Synthesis And Application Of Thiophene-2,5-dicarboxylic Acid And Naphthalic Anhydride Derivatives

In this paper,seven compounds were synthesized based on thiophene dicarboxylicacid and naphthalic anhydride by us.They are 5-?benzo[d]oxazol-2-yl?thiophene-2-carbohydrazide?L1?,?Z?-5-?benzo[d]oxazol-2-yl?-N'-?pyridin-2-ylmethylene?hiophene-2-carbohydrazide?L2?,?Z?-N'-?2-hydroxybenzylidene?-5-?benzo[d]oxazol-2-yl?thiophene-2-carbohydrazide?L3?,?benzo[d]xazol-2-yl?thiophene-2-carboxylicacid?L4?,Benzimidazol and benzoiso quinolone derivatives B2,B3,B4.The way of characterize B2 is1H NMR,13C NMR spectra,and use fluorescence emission and UV-vis absorbance to investigate their optical properties.As show in result,we can find the compound can be used for fluorescent probe.We find compound L1 and L2,L3 and L4 are based on thiophene dicarboxylic acid.The results showed that L1,L2,L3 showed no response to the pH and metal ions In acetonitrile/water?9/1?system,L4 showed a good fluorescence response to the pH.The acidity increasing,the probes express blue fluorescence.In DMF/H₂O?9:1?system,the cis-structure of B2?2.7¹1?,B4?2.7¹1?are no response to pH.In DMF/H₂O?9:1?Tris buffer solution B2,B4 showed highly selective and sensitive to Fe³⁺,and the probes exhibited highly fluorecence intensity.With the increase of the Fe³⁺,the probes showed fluorecent non fluorescence.Other metal ions can not interference detection and probes showed good reversibility.The stoichiometry ratio of the sensor to Fe³⁺was 1:1.The detection limit of Fe³⁺was 5×10^-7M in buffer solution?DMF:H₂O=9:1,pH=7.4?.Therefore,this sensor has the ability to be a practical system for detecting Fe³⁺concentrations in aqueous samples.