波谱学杂志 ›› 1994, Vol. 11 ›› Issue (3): 251-256.

• 研究论文 • 上一篇    下一篇

直接键连原子间的NMR偶合常数的自然杂化轨道研究Ⅲ、α-C-H键核自旋偶合常数1JCH

湛昌国1, 胡振明1,2   

  1. 1. 华中师范大学化学系, 武汉 430070;
    2. 湖北师范学院化学系, 黄石 435002
  • 收稿日期:1993-08-25 修回日期:1994-01-14 出版日期:1994-09-05 发布日期:2018-01-20
  • 基金资助:
    国家自然科学基金资助课题并获湖北省教委科研基金

THE STUDY OF THE NUCLEAR SPIN-SPIN COUPLING CONSTANTS BETWEEN DIRECTLY BONDED ATOMS BY NATURAL HYBRID ORBITALS Ⅲα-C-H Nuclear Spin-Spin Coupling Constants 1JCH

Zhan Changguo1, Hu Zhenmin1,2   

  1. 1. Department of Chemistry, Central China Normal University, Wuhan 430070;
    2. Department of Chemistry, Hubei Nonnal University, Huangshi 435002
  • Received:1993-08-25 Revised:1994-01-14 Online:1994-09-05 Published:2018-01-20

摘要: 报道了一种计算直接键连原子间的核自旋-自旋偶合常数的通用关系式,结合CNDO/2分子轨道方法和自然杂化轨道方法,具体计算了一些极性α-C-H键的核自旋偶合常数。结果表明,本文方法适合于多种类型的直接键连原子间的偶合常数的计算,且与已有实验值吻合一致.

关键词: 核自旋-自旋偶合, 偶合常数, 杂化轨道, s轨道成份, 净电荷

Abstract: In this paper,a general relationship between the nuclear spin-Spin coupling con-stants(1JAB) across one bond and the s-character of hybrid orbitals and atomic net charges of atonis A and B is foimulated. The relationship obtained is applied to calcu-lation of the α-C-H coupling constants:1JCH for a series of substituted hydrocarbons by use of the CNDO/2 molecular orbital approximation and natural hybrid orbital scheme.It is verified that the JCH values are crudely correlated with carbon hybridiZation and bond polarity.The latter becomes important for α-C-H coupling constants for liydrocarbons containing heteroatoms or substituents.Some discussions concerning the ealculatcd results and the factors which affect the coupling constants are also reported.

Key words: Nuclear spin-spin coupling, Coupling constants, Hybrid orbitals, s-Characters, Net charges