The relationship between proton-proton NMR coupling constants and substituent electronegativities—I : An empirical generalization of the karplus equation

doi:10.1016/0040-4020(80)80155-4

Tetrahedron

Volume 36, Issue 19, 1980, Pages 2783-2792

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Abstract

A new coupling constant-torsion angle relation for the three-bond ¹H-¹H spin-spin coupling constant is formulated. The relation includes a correction for the electronegativity of substituents. The correction term is written as a function of the electronegativity, the H-C-C-H torsion angle, and the orientation of each substituent relative to the coupled protons. A dataset consisting of 315 experimental coupling constants was used to derive six empirical parameters by means of an iterative least-squares minimization procedure. The precision of the proposed equation, expressed as the root-mean-square deviation (0.48 Hz), is superior to any hitherto reported. It is shown that separate treatment of CH₂CH₂, CH₂CH and CHCH fragments even improves this precision. An application in the field of monosubstituted cyclohexanes is given.

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The relationship between proton-proton NMR coupling constants and substituent electronegativities—I : An empirical generalization of the karplus equation

Abstract

Tetrahedron

J. Am. Chem. Soc.

Adv. Phys. Org. Chem.

J. Chem. Phys.

J. Am. Chem. Soc.

J. Chem. Phys.

J. Am. Chem. Soc.

Biochemistry

Biopolymers

Mol. Phys.

Org. Magn. Res.