A CRITICAL EVALUATION OF DEPENDENCE OF 3JHH COUPLINGS ON BOND ORDER AND BOND LENGTH IN CONJUGATED CARBOCYCLIC MOLECULES . EVIDENCE FOR A STERIC EFFECT ON 3JHH
A CRITICAL EVALUATION OF DEPENDENCE OF 3JHH COUPLINGS ON BOND ORDER AND BOND LENGTH IN CONJUGATED CARBOCYCLIC MOLECULES . EVIDENCE FOR A STERIC EFFECT ON 3JHH
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DOI：
10.1021/ja01051a024
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发表时间：
1969-01-01
影响因子：
15
通讯作者：
MANATT, SL
中科院分区：
文献类型：
--
作者：
COOPER, MA;MANATT, SL
先前提出的键序与不饱和体系中核磁共振正位质子-质子自旋-自旋耦合常数（3/）的大小之间的线性相关关系已经被重新研究，使用了比以前更精确的耦合常数值。结果表明，尽管在整个键序范围内，该关系不再是线性的，但对于芳香体系，该曲线仍然是近似线性的。线性的偏离显示出一致的趋势，这可以在空间相互作用方面合理化。在整个键长范围内，3J与键长呈线性关系，并根据简单的分子轨道理论以及先前提出的价键处理方法讨论了这种相关性的理论背景。
Previously proposed linear correlationsbetween-bond orders and the magnitudes of nmr ortho proton-proton spin-spin coupling constants (3/) in unsaturated systems have been reinvestigated using more accurate values for the coupling constants than were available heretofore. It is shown that, although the relationship is no longer linear over the whole range of bond order, the plot is still approximately linear for aromatic systems. Deviations from linearity are shown to exhibit consistent trends, which may be rationalized in terms of steric interactions. A plot of 3J vs. bond length is shown to be linear over the whole range of bond lengths, and the theoretical background of this correlation is discussed in terms of a simple molecularorbital theory, as well as a previously pro-posed valence bond treatment.