摘要
用ＡＭ１方法计算了几种甲氧基苯酚的ΔＨＯＦ值，以此为理论指标探讨了甲氧基氧的ｐ型孤对电子对苯氧自由基的稳定作用。发现ｐ型孤对电子对邻、对位苯氧自由基的稳定作用较强，对间位自由基没有稳定作用，呈现出明显的位置效应。同时ｐ型孤对电子轨道的扭转对稳定作用有较大影响。当轨道与苯环平面垂直时，稳定作用最强，而当轨道与苯环平面平行时，稳定作用最弱。最后将上述结果用于黄酮类抗氧化剂和维生素Ｅ，阐明了许多实验现象。
AM1 method was employed to calculate ΔHOF values of methoxyl phenols, and the values were used as theoretical parameters to investigate the stabilizing effect of p-type lone pair electrons of methoxyl oxygen on the phenoxyl free radicals. It was found that the stabilizing effect of the p-type lone pair electrons displayed distinct site-effect. The phenoxyl free radicals at ortho or para position were well stabilized, but the radical at meta position was hardly stabilized. Meanwhile, rotation of the p-type lone pair orbital had considerable influence on the stabilizing effect. When the orbital was perpendicular to the aromatic plane, the stabilizing effect was the highest, and when the orbital was parallel to the plane, the effect was the lowest. Above results were also applied to flavonoid antioxidants and vitamin E to elucidate many experimental phenomena.
出处
《生物物理学报》
CAS
CSCD
北大核心
1999年第2期360-373,共14页
Acta Biophysica Sinica
基金
山东师范大学博士科研启动基金
关键词
量子化学计算
AM1方法
苯氧自由基
抗氧化剂
Quantum chemical calculation AM1 method Phenoxyl free radical Antioxidant Structure-activity relationships
