Imaging Science and Photochemistry ›› 2018, Vol. 36 ›› Issue (5): 425-433.DOI: 10.7517/issn.1674-0475.180408

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Synthesis and Properties of a pH Fluorescent Probe Based on PET Mechanism

CHANG Shunzhou1, XIANG Kaiqiang2, MING Wei2, ZHANG Zhizhong1, TIAN Baozhu2, ZHANG Jinlong2   

  1. 1. Research Institute of Physical and Chemical Engineering of Nuclear Industry, Tianjin 300180, P. R. China;
    2. Key Laboratory for Advanced Materials, School of Chemistry & Molecular Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China
  • Received:2018-04-20 Revised:2018-05-16 Online:2018-09-15 Published:2018-09-15

Abstract: A novel pH fluorescent probe (DCM-PA) was synthesized by employing dicyanomethylene-4H-pyran derivative as the fluorophore and piperazine as the response unit. The maximum absorption wavelength(λabs) and maximum emission wavelength(λem) were tested to be 421 nm and 590 nm, respectively. This means that the stokes shift is near to 170 nm. It was found that the fluorescence intensity gradually increased with the increase of pH value in the pH range of 2-12. The pKa of DCM-PA was determined to be 7.2. In the range of pH=6-9, there exists a good linear relationship between the fluorescence intensity and pH value. The response mechanism of the pH probe was revealed by the control experiment:Under acidic conditions, the electron donating ability of piperazine group will weaken after combining with proton, leading to the enhancement of the fluorescence intensity. Under alkaline conditions, the fluorescence will be quenched by the photoinduced electron transfer (PET) process. Moreover, it was found that DCM-PA exhibited a good anti-interference ability to different cations and anions.

Key words: fluorescent probe, pH, dicyanomethylene-4H-pyran, photoinduced electron transfer