Spectroscopic Detection, Reactivity, and Acid−Base Behavior of Ring-Dimethoxylated Phenylethanoic Acid Radical Cations and Radical Zwitterions in Aqueous Solution
作者:Massimo Bietti、Alberto Capone
DOI:10.1021/jo035492n
日期:2004.1.1
aromatic radical cations or radical zwitterions depending on pH, and pKa values for the corresponding acid−base equilibria have been measured. The radical cations undergo decarboxylation with first-order rate constants (kdec) ranging from <102 to 5.6 × 104 s-1 depending on radical cation stability. A significant increase in kdec (between 10 and 40 times) is observed on going from the radical cations to the
环二甲氧基化苯基乙酸的单电子氧化的产物和时间分辨动力学研究已在不同的pH值下进行。氧化会导致形成取决于pH的芳族自由基阳离子或两性离子,并且已经测量了相应酸碱平衡的p K a值。的自由基阳离子经历与一级速率常数(脱羧ķ分解)范围为<10 2至5.6×10 4小号- 1取决于自由基阳离子的稳定性。k dec显着增加(从10到40次之间)观察到从自由基阳离子到相应的自由基两性离子。根据自由基阳离子和自由基两性离子中脱羧所需的分子内侧链到环电子转移的难易程度来讨论结果。