最大重迭分子轨道和核自旋偶合常数的计算

The maximum overlap symmetry molecular orbital and calculation of nuclear spin-spin coupling constants

利用前文中建立的AM1级别上最大重迭对称性分子轨道计算方案，并结合最大键级杂化轨道方法，在对分子几何优化的基础上，计算系列化合物分子中各原子的电荷分布和杂化轨道组成系数，拟合出计算C-H及C-C偶合常数的简单关系式，计算各种分子中不同C-H键和C-C键偶合常数，所得计算值和实验数据较为吻合，两者相关系数和标准偏差：1JCH为0．9820和6．0205，IJCC为0．9888和7．3462，为计算1JCH和1JCC提供简便而直观的方法。建立的公式可预测新化合物中的C-H及C-C偶合常数，对新化合物的性质和结构及成键情况也能起到辅助推断作用，且在大分子体系的研究中极易推广。计算结果进一步表明所建AMI级别上最大重迭对称性分子轨道计算方法是可行的。

By using of the density matrix and the net atomic charges obtained from calculation procedure of the maximum overlap sym- metry molecular orbital （MOSMO） method under AM1 approximation presented in previous paper, the maximum bond order hybrid or- bital （MBOHO） procedure has been performed. Further, the correlativity between the MBOHO calculation results and the nuclear spin-spin coupling constants of the directly bonded C--H and C--C bonds has been obtained. The coupling constants calculated by use of the concrete relationships are all in good agreement with the experimental data. Thus, it further illustrate that MOSMO method under AM1 approximation is reasonable.