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￣（1）J＿（cH）  

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 ~1J_(CH)

作　　者：湛昌国[1] 胡振明[1] 

机构地区：[1]华中师范大学化学系,湖北师范学院化学系

出　　处：《波谱学杂志》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

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。

关 键 词：核自旋耦合 NMR 耦合常数 

分 类 号：O641.13[理学—物理化学]