稠环芳烃系列化合物化学位移的计算 IV.^1H化学位移加合性规律的量子力学基础

The calculation of chemical shifts of condensed aromatic hydrocarbon shifts iv. Quantum mechanical basis of additivity rule for proton chemical shifts

Based on a starting point of the McWeeny Huckel-London perturbation theory approximation, a formula similar to the fourmula of additivity rule for the calculations of the chemical shifts of condensed aromatic hydrocarbons has been derived. The quantum mechanical basis of additivity rule is thus indicated by this formula. It is shown that by using the concept of aromatic shift and sigma ratio, this method for calculation of proton chemical shifts has the virtues of definite physical meaning and simple calculation. It can also be extended to the calculation of the proton chemical shifts of substituents fr the molecules of this series.