关键词: 几何异构, 分子轨道方法, 硝酸酯

Semi-empirical SCF-MO calculations by MINDO / 3, MNDO and AM1 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-hydro- xyethyl)-amine dinitrate, nitroglycerine and pentaerythrite tetranitrate), it is found that AM1 method is better than the other methods for predicting molecular geometry. The -ONO~2 groups in molecules of various nitrates have approximately the same value of geometrical0 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.

Key words: MOLECULAR ORBITAL METHOD, GEOMETRICAL ISOMERISM, NITRATE