一个发射波长明显红移的二苯乙烯类pH探针

该文选用有别于文献报道的合成路线合成并表征了4-二甲胺基-4′-二苯胺基二苯乙烯(DPVP)。当pH从7.04减小到2.90时,c(DPVP)=1.0μmol/L的V(水)/V(乙醇)=1溶液的紫外-可见吸收强度减弱,且变化灵敏。当该溶液的pH从7.04减小到4.20时,荧光强度减弱相对较慢,最大发射波长保持不变,且pKa=6.13±0.07;当pH从4.20继续减小到2.65时,荧光强度减弱相对较快,最大发射波长持续红移,直至最终红移12 nm,且pKa=3.48±0.01。荧光减弱的原因是二甲胺基上的氮原子质子化。该化合物是一个很好的pH荧光探针,pH响应灵敏,检测pH范围为7.04~2.65。

A Probe of Stilbene Derivative for pH with Distinct Red Shift in Emission Wavelength

4-Dimethylamino-4′-diphenylaminostilbene(DPVP) was synthesized and characterized.The UV-vis absorbance of DPVP(1.0 μmol/L) in the solution of water and ethanol(V(H2O)/V(C2H5OH)=1)sensitive to pH changes over a wide range from 7.04 to 2.90,and a gradual decrease in absorption intensity upon pH ranging from 7.04 to 2.90 were observed.A tardy decline in fluorescence intensity and a fixed maximum emission wavelength at pKa equal to 6.13±0.07 were found upon a drop in pH from 7.04 to 4.20,while a rapid reduction in fluorescene intensity and a distinct and final red shift of 12 nm in maximum emission wavelength at pKa equal to 3.48±0.01 were also found upon a fall in pH from 4.20 to 2.65.The protonation of nitrogen of dimethylamino group led to the attenuation of fluorescene.DPVP is a highly sensitive sensor for pH ranging from 7.04 to 2.65.