【摘要】 本文通过对环状磷酸酯和环状亚磷酸酯类化合物的分子力学计算,观察到¹⁷O NMR化学位移的变化同时受到氧原子局部范德华相互作用能(E_VDW-O)和局部偶极相互作用能(E_dip-o)的影响.此外,在上述两类化合物中,环外氧原子的δ-压缩效应极为明显,这主要是由于该氧原子局部范德华相互作用能起决定作用的缘故.同时,经对二烷基砜类化合物的分子力学计算,首次获得³³S NMR化学位移和硫原子局部范德华相互作用能 E_VDW-S之间良好的线性关系.更多还原

【Abstract】 Molecular mechanics studies of the steric energies of cyclic phosphates and phosphites reveal that the magnitude of the 17O NMR chemical shift is not only determined by the local van der Waals interaction energy, but also influenced by the local dipole interaction energy. Furthermore, the δ-compression effect of the exocyclic oxygen plays an important role in this respect, as the result of the local van der Waals interactions. As found by us the 33S NMR chemical shift of dialkylsulfones is linearly correlated with the local van der Waals interaction energy, the regression analysis provides an excellant correlation coefficient.更多还原