The effect of protonation on the photophysics and especially on the excited state dynamics of two pyrimidine chromophores, bearing the A-(π-D)₂ and A-(π-D)₃ structure, is studied by means of fs-ps and ns time resolved fluorescence spectroscopy. Three different acids, namely camphorsulphonic (CSA), acetic (AcOH) and trifluoroacetic acid (TFA) were used. The chromophores bear the pyrimidine electron deficient heterocycle as electron-withdrawing group, used as protonation site, as well as diphenylamino electron donors. Protonation is revealed through the emergence of red-shifted absorption and fluorescence bands accompanied by a quenching of the fluorescence of the neutral molecules. Time-resolved dynamics reveal that protonation with CSA and TFA do not influence the excited state lifetime of the chromophores, pointing to a static quenching process. On the other hand, the lifetime is decreased upon protonation with AcOH. Further investigation based on the Stern-Volmer plots showed that addition of AcOH leads to both dynamic and static quenching.

质子化对光物理的影响，特别是对两个带有A-（π-D）₂和A-（π-D）_3的嘧啶发色团的激发态动力学的影响fs-ps和ns时间分辨荧光光谱法研究了其结构。使用了三种不同的酸，即樟脑磺酸（CSA），乙酸（AcOH）和三氟乙酸（TFA）。发色团带有嘧啶电子缺陷的杂环作为吸电子基团（用作质子化位点），以及二苯氨基电子供体。通过出现红移的吸收带和荧光带并伴随中性分子的荧光猝灭来揭示质子化。时间分辨动力学表明，CSA和TFA的质子化不会影响发色团的激发态寿命，这表明是静态猝灭过程。另一方面，当用AcOH质子化时，寿命降低。