Synthesis And Properties Studies Of Novel Rhodamine Fluorescent Probes

Chemical fluorescent molecular probes with high monitoring sensitivity, lowdetection limit, good selectivity, fast response, etc., are widely used to detect metalcations, anions and small molecules. Rhodamine dye molecules have large π bond anda rigid planar structure, which makes they have good photophysical properties, such ashigh light quantum yield, good light stability, high fluorescence emission efficiency,wide wavelength range, etc..In addition, rhodamine dye has the advantage of cheap,low toxicity, high water solubility, pH-insensitive, etc., which makes it one of the mostimportant precursors to synthesize chemical fluorescent probe. The excessive intake ofAl3+, Fe3+, CN-, etc., will cause a great threat to human life and health, such as Al3+toxicity causes microcytic hypochromic anemia, Al-related bone disease(ARBD), andAlzheimer’s disease, etc. So in recent years, many scientists synthesized a number ofrhodamine fluorescent probes for the detection of ions. But most previous reports ofrhodamine fluorescence probes could detect only one kind of ions.This paper describes a new rhodamine fluorescence probe2-1which can detectAl3+, Fe3+, CN-, and H+ions in different testing conditions. At room temperature,inHEPES buffer (0.01M)(CH3CN:water,1:1, v/v, pH<4.4),2-1has a very good abilityto recognize Al3+. The fluorescence intensity enhanced when the Al3+was added, andthe colour of the solution gradually changed from colorless to pink. In HEPES buffer(0.01M)(CH3CN:water,9:1, v/v, pH5.5),2-1has a very good ability to recognizeFe3+,the fluorescence intensity enhanced when Fe3+was added, and the colour of thesolution gradually changed from colorless to pink.2-1bonded respectively with Al3+and Fe3+to form complexations. The ions induced spirolactam ring-opening of2-1.The fluorescence enhancement of the systems could be quenched when CN-wasadded,and the colour changed from pink to coloreless. Other anions didn’t cause thesame colour changes, So,2-1could recognize CN-. In the citrate buffer solution(acetonitrile/water1:9, V/V, pH3-6), the fluorescence intensity enhanced with thedecrease of pH, the solution changed from colorless to pink. So2-1could detect andrecognize H+selectively. Therefore, compound2-1can be developed into a variety of ion detection, high-performance fluorescent probe.