Synthesis of 1,5-Diaryl-3-(2-hydroxyl-4,6-dimethoxylphenyl) -2-pyrazolines as Fluorescent Sensors for Fluoride Ion

The design and synthesis of chemosensors for Cu2+ constitute a very active area of research as a result of the demand for more sensitive and selective chemosensors for in vitro and in vivo purposes.The synthe-tic Cu2+ selective fluoroionophores so far reported suffer from low sensitivity and,in general,higher concentrations of interfering metal ions disturb the selectivity towards Cu2+.Four 1,5-diaryl-3-(2-hydroxyl-4,6-dimethoxylphenyl)-2-pyrazoline(4a—4d) were synthesized and fluorescent sensors for Cu2+ ion were investigated.The structures of all the products were determined by IR,1H NMR,MS and elemental analysis.Their UV and fluorescence spectra were measured.The influences of eight metal ions such as Cu2+,Zn2+,Co2+,Ni2+,Na+,K+,Ca2+and Mg2+ on their fluorescence properties were studied.Spectroscopic studies revealed that the compounds 4a—4d had rather strong affinity toward Cu2+.The specificity of the probes 4a—4d toward Cu2+ were determined.Nearly no fluorescence intensity changes were observed in emission spectra with Zn2+,Co2+,Ni2+,Na+,K+,Ca2+ and Mg2+.However,under identical conditions,the results show fluorescence quenching with Cu2+.So we have developed four new fluorescent sensor 4a—4d.They show high sensitivity and selectivity toward Cu2+ in DMSO.