荧光素与中性红酸、碱染料间荧光共振能量转移机理

应用荧光光谱法研究了水溶液体系中酸性染料四溴荧光素(TBF)、四碘荧光素(TIF)、四氯四碘荧光素(TCTIF)、四氯四溴荧光素(TCTBF)分别与碱性染料中性红(NR)之间的相互作用.实验表明:NR对各酸性染料的荧光都有较强的猝灭作用,据此求得不同温度下NR与各种酸性染料的结合常数K.发现K值随反应温度上升而下降,且随酸性染料取代基的电负性增加而增大,证实了该反应为单一静态猝灭过程.由反应焓变、熵变确定NR与酸性染料间的结合力主要是静电引力.依据非辐射能量转移机理,探讨了不同温度下各酸性染料与NR相互结合时,能量转移效率、能量给体与受体间距离r等参数,各体系r7 nm表明该荧光猝灭是通过非辐射能量转移过程产生的.并发现随着染料取代基的电负性增加,能量转移参数的某些变化规律.

Study of Fluorescence Resonance Energy Transfer Mechanism Between Acidity and Alkalinous Dyes-fluorescein and Neutral Red

In the aqueous solution,the reactions between alkalinous dyestuff neutral red(NR) and various acidity dyestuff including tetrabromofluorescein(TBF),tetraiodofluorescein(TIF),tetrachlorotetra-iodofluorescien(TCTIF),and tetrachlorotetrabromofluorescien(TCTBF) have been investigated by fluorescence spectra.The experimental results showed that NR can quench the fluorescence of various acidity dyestuff.The binding constants K of acidity dyes and NR at various temperatures were calculated through the results.It could be found that the binding constant K decreases with increasing reaction temperature and increases with increasing the electronegativity of substituting group of dyes.The result showed that the quenching mechanism of NR and acidity dyestuff was a static procedure.The interactions between NR and various acidity dyestuffs were attributed to static-electricity gravitation which was confirmed by the calculation results of enthalpy and entropy for these reactions.According to the non-radiation energy transfer theory,the acceptor-donor distances(r) and energy transfer efficiencies between NR and various acidity dyestuff at various temperatures were obtained.These results further supported the conclusion that if r was within 7 nm,these reactions belonged to the single static quenching which was caused by the non-radiation energy transfer.It could be found some regularity among the parameters of energy transfer along with the increase in the electronegativity of substituting group of dyes.