直接键连原子间的NMR偶合常数的自然杂化轨道研究V.^(13)C-^(13)C和^(13)C-^(31)P核自旋偶合常数~1J_(CC)和~1J_(CP)

THE STUDY OF THE NUCLEAR SPIN SPIN COUPLING CONSTANTS BETWEEN DIRECTLY BONDED ATOMS BY NATURAL HYBRID ORBITALS

在前文工作的基础上，结合ＭＮＤＯ／ＥＨＭＯ分子轨道方法和自然杂化轨道方法，具体计算了ＣＣ键和ＣＰ键的核自旋偶合常数．计算结果表明，１ＪＣＣ和１ＪＣＰ主要由成键原子的轨道杂化作用和键极性这两种结构因素所决定．为从简单价键理论角度解释和计算１ＪＣＣ和１ＪＣＰ值提供了简便直观的方法．

The novel generalized correlation of the nuclear spin spin coupling constants with the atomic hybrids and net charges is employed to give new concrete relationships for calculating the directly bonded carbon carbon and carbon phosphorus coupling constants by use of the natural hybrid orbital procedure together with the MNDO/EHMO calculation. The calculated values are well in agreement with the experimental data, which suports the idea that the hybridization and bond polarity, and the Fermi contact term are dominant factors in determining carbon carbon and carbon phosphorus spin spin coupling constants across one bond. Thus one is able to interpret and calculate the\ 1J CC and\ 1J CP values based on the simple valence bond theory.