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．
In this paper，a general relationship between the nuclear spin-Spin coupling con-stants（~1J_(AB)）across one bond and the s-character of hybrid orbitals and atomic netcharges of atonis A and B is foimulated． The relationship obtained is applied to calcu-lation of the α─C─H coupling constants：~1J_(CH) for a series of substituted hydrocarbonsby use of the CNDO／2 molecular orbital approximation and natural hybrid orbitalscheme。 It is verified that the J_(CH) values are crudely correlated with carbonhybridiZation and bond polarity．The latter becomes important for α─C─H couplingconstants for liydrocarbons containing heteroatoms or substituents。 Some discussionsconcerning the ealculatcd results and the factors which affect the coupling constantsare also reported。
出处
《波谱学杂志》
CAS
CSCD
1994年第3期251-256,共6页
Chinese Journal of Magnetic Resonance
基金
国家自然科学基金
湖北省教委科研基金
关键词
核自旋耦合
NMR
耦合常数
Nuclear spin-spin coupling，Coupling constants， Hybrid orbital8，s-Characters，Net charges
