Acid–base strength and acido(fluoro)chromism of three push–pull derivatives of 2,6-distyrylpyridine
作者:Letizia Mencaroni、Alessio Cesaretti、Fausto Elisei、Irena Škorić、Milena Mlakić、Anna Spalletti
DOI:10.1007/s43630-022-00184-5
日期:2022.6
6-DStP, also because of the second protonation by the N(CH3)2 group. Spectrophotometric titrations, also processed by a global fitting approach, gave pKa values, for the protonation of the central pyridine, higher in the derivatives with electron-donor unities and lower in compounds bearing electron-acceptor groups. A fluorometric titration was performed in the case of the dimethylamino-derivative thanks
2,6-二苯乙烯基吡啶 (2,6-DStP) 衍生物的酸致变色和酸碱性质,其两侧带有推/拉取代基(即两个二甲氨基、一个硝基、一个甲氧基和两个硝基,在 2 的情况下, 6-双[(E)-2-(4-二甲基氨基苯基)乙烯基]吡啶, 2-[(E)-2-(4-硝基苯基)乙烯基],6-[(E)-2'-(4'-甲氧基苯基)乙烯基]吡啶和2,6-双[(E)-2-(4-硝基苯基)乙烯基]吡啶,分别)通过固定和时间分辨光谱进行研究。发现吸收和发射光谱对中等酸度的敏感性相对于未取代的 2,6-DStP 在二甲氨基衍生物中增强,这也是因为 N(CH 3 ) 2的第二次质子化团体。分光光度滴定法,也通过全局拟合方法处理,给出了中心吡啶质子化的 pKa 值,在具有电子供体单元的衍生物中较高,而在带有电子受体基团的化合物中较低。由于中性和质子化物质的发射效率不可忽略,因此在二甲氨基衍生物的情况下进行了荧光滴定,在吡啶质子