The Thermal Isomerization of Azobenzenes. III. Substituent, Solvent, and Pressure Effects on the Thermal Isomerization of Push-pull Azobenzenes
作者:Norio Nishimura、Shinya Kosako、Yoshimi Sueishi
DOI:10.1246/bcsj.57.1617
日期:1984.6
4-(dimethylamino)azobenzene (DAAB) derivatives, and no fundamental difference in the kinetic-substituent effects was observed between NDAAB and DAAB. The volume of activation, which is of a negative value, varies remarkably from solvent to solvent and from substituent to substituent; its magnitude increases generally with an increase in the solvent polarity. Even for DAAB and 4,4′-bis(diethylamino)azobenzene (BDEAAB)
研究了取代基、溶剂和压力对 4-二甲氨基-4'-硝基偶氮苯 (NDAAB) 衍生物的热顺反异构化速率的影响。2-甲基-和 2'-氯-NDAAB 异构化速度比 NDAAB 快,2'-甲基-和 2-氯-NDAAB 异构化速度比 NDAAB 慢。对于 2,2'-二甲基-和 2,2'-二氯-NDAAB,速率介于单取代的速率之间。这些发现与 4-(二甲氨基)偶氮苯 (DAAB) 衍生物的发现非常相似,在 NDAAB 和 DAAB 之间没有观察到动力学取代基效应的根本差异。活化体积为负值,随溶剂和取代基的不同而显着变化;它的大小通常随着溶剂极性的增加而增加。即使对于 DAAB 和 4,4'-双(二乙氨基)偶氮苯 (BDEAAB),极性溶剂中的外部压力可明显加快该速率。得出的结论是,观察到的结果与逆...