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该文采用Diels-Alder反应,以4-卤代(氟、氯、溴)间苯二酚与邻苯二甲酸酐为原料,在甲基磺酸催化剂作用下合成了2’,7’-二卤代荧光素(DFF、DCF、DBF)。对化合物的结构进行了表征。pH滴定实验表明,化合物(DFF、DCF、DBF)的紫外吸收与荧光发射光谱均对溶液的pH有较强的敏感性。DFF、DCF、DBF分别在490、502、505 nm处的吸收强度和在517、526、530 nm处的荧光强度均随着pH增加而增大;当溶液的pH>10,其吸收强度与荧光强度基本保持不变。DFF、DCF和DBF的热力学常数pKa值随着卤族元素的原子序数的增加依次增大,分别是4.7、5.1、6.6;其荧光量子产率依次减小,分别是0.97、0.94、0.67。光降解实验结果表明,化合物的光稳定性大小依次是DFF>DCF>FL(荧光素)>DBF。
Diels-Alder reaction was used to synthesize 4-halo (fluorine, chlorine and bromine) resorcinol and phthalic anhydride as raw materials. Under the action of methanesulfonic acid catalyst, 2 ’, 7’- Halogen fluorescein (DFF, DCF, DBF). The structure of the compound was characterized. pH titration experiments showed that UV absorption and fluorescence emission spectra of the compounds (DFF, DCF, DBF) were highly sensitive to the pH of the solution. The absorption intensity at 490, 502 and 505 nm and the fluorescence intensity at 517, 526 and 530 nm of DFF, DCF and DBF increased with the increase of pH respectively. When the pH of the solution was> 10, the absorption intensity and fluorescence The basic strength remained unchanged. The thermodynamic constants pKa of DFF, DCF and DBF increase with the increase of the atomic numbers of halogens, which are 4.7, 5.1 and 6.6, respectively. The fluorescence quantum yields decrease sequentially, which are 0.97, 0.94 and 0.67 respectively. The results of photodegradation showed that the photostability of the compounds was in order of DFF> DCF> FL (fluorescein)> DBF.