直接键连原子间的NMR偶合常数的自然杂化轨道研究——Ⅰ.^(13)C—H核自旋偶合常数~1J_(^(13)C-H)

The Study of the Nuclear Spin-Spin Coupling Constants Between Directly Bonded Atoms by Natural Hybrid Orbitals Ⅰ. ^(13)C-H Nuclear Spin-Spin Coupling Constants ~1J^(13)c-H

利用CNDO/2分子轨道方法和自然杂化轨道方法,计算了一系列碳氢化合物和含杂原子的碳氢化合物的自然杂化轨道。在此基础上,得到了计算^(13)C—H偶合常数~1J13_(C-H)的简单关系式。对75种不同化学环境下的~1J13_(C-H)的计算结果表明,无论是碳氢化合物系列,还是含杂原子的碳氢化合物系列,计算值与已知实验值都较为吻合。本文还对计算结果作了较详细的讨论。

Based on the CNDO/2-SCF-MO calculation and the natural hybrid orbitals scheme, the simple relationships between nuclear spin-spin coupling constants 1J13c-13c and the s-characters of natural hybrid orbitals of C atoms are reported in this paper. It is shown that the calculated results for 32 different 1JcCc values are in good agreement with the experimental data. Some discussions of the calculated results and the factors which affect the coupling constants are also reported.