硝酸酯分子几何构型的量子化学研究

运用MINDO / 3、MNDO 和AM1 三种半经验分子轨道(MO)方法, 通过SCF计算, 首次系统地获得了32个硝酸酯化合物分子的全优化几何构型。三种方法的计算结果与已报道的四个化合物(硝酸甲酯、吉纳、硝化甘油和太安)的实验结果相比, AM1法较好。所有硝酸酯的酯基(-ONO~2)具有近似不变的几何参数。直链烷基硝酸酯的键长和键角极为相近, 全部重原子均共平面。二元直链和四元硝酸酯具有对称的分子构型。

Quantum-chemical studies on geometries of nitrate molecules

Semi-empirical SCF-MO calculations by MINDO/3, MNDO and AMI have been performed to obtain molecular geometries of 32 nitrates by complete optimization. The results calculated from the three methods are similar to each other. By comparing with the experimental geometries of four compounds (i.e., methyl nitrate, N- nitrobis(2-hydroxyethyl)-amine dinitrate, nitroglycerine and pentaerythrite tetranitrate), it is found that AM 1 method is better than the other methods for predicting molecular geometry. The -ONO2 groups in molecules of various nitrates have approximately the same value of geometrical parameters. The bond lengths and bond angles of straight-chain alkyl nitrates are akin to each other, and all heavy atoms in the molecules are coplanar at their trans-conformations. The bisubistituted straight-chain and tetrasubstituted ester molecules have symmetrical structures.