摘要
分子轨道理论中,将HMO方法的各种量化参数与化学反应活性相联系的研究,如利用键序、自极化率、前线轨道能级、总电荷密度、超离域度、自由价等量化参数来预测各种反应活性,取得了不少有意义的结果。利用其它半经验方法(如CNDO/2)的量化参数,如Mulliken重叠集居数,极化率,超离域度,总电荷密度来预测某些化合物的活性,也见诸于一些文章,得到了较好的线性回归方程。本文利用从头计算法,采取STO-3G基集计算了某些含氧酸分子,如H_2O,H_2O_2;HNO_2,HNO_3;HClO,HClO_2,HClO_3;HCO_2H,CH_3CO_2H等的电子结构,它们的标准几何构型取自已知的实验数据。将氢、氧原子上的总电荷密度以及氧原子上的亲电子超离域度与实验测得的酸性离解常数相联系,应用多元回归法,得到了较好的线性关系。
The electronic structures of several oxygen-containing acids (H_2O, H_2O_2, HNO_2,
HNO_3, HClO, HClO_2, HClO_3, HCO_2H, CH_3CO_2H)have Been calculated by ab initio method
(STO-3G). It is found that there exists a linear relationship between their acidities
(pK_a) and electrophilic superdelocalizabilities (S_O^(E)) of oxygen atom as well as the net
atomic charge of oxygen atom and hydrogen atom in the hydroxyl group. A mechanism
was proposed for the dissociation process and polymerized configuration.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1989年第3期284-287,共4页
Acta Chimica Sinica
