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In nuclear chemistry and nuclear physics, J-couplings (also called spin-spin coupling or indirect dipole–dipole coupling) are mediated through chemical bonds connecting two spins. It is an indirect interaction between two nuclear spins that arises from hyperfine interactions between the nuclei and local electrons. [1]
A J-coupling is an interaction between nuclei containing spin. J-couplings are also known as scalar couplings. This interaction is mediated through bonds, in contrast to dipole interactions, which are mediated through space. Typically, we consider the J-coupling to be a weak interaction, in comparison to the Zeeman interaction.
The coupling constant, J (usually in frequency units, Hz) is a measure of the interaction between a pair of protons. In a vicinal system of the general type, a b then the coupling of a with b, J ab , MUST BE EQUAL to the coupling of b with a, J ba, therefore J ab = J ba . The implications are that the spacing between the lines in the coupling ...
J coupling is the interaction between magnetic nuclei via chemical bonds and electron spins. It affects NMR spectra, resonance assignment, and 3D structure determination of molecules. Learn about its physical basis, nomenclature, measurement methods, and applications in proteins and nucleic acids.
16 de jul. de 2019 · 114. 13K views 4 years ago Organic Chemistry Analytical Techniques: Nuclear Magnetic Resonance (NMR) Here we talk about J-coupling, where it comes from, and how it affects NMR spectra ...more ...
Learn how J-coupling arises from nuclear magnetic moments in the same molecule affecting each other through the electron cloud, and how it can be used to identify and analyze molecules. Understand the nomenclature and the secular approximation for different types of J-couplings, and see examples of spectra and splittings.
There are two descriptions for the coupling of angular momentum. One is called j-j coupling, and the other is called L-S coupling. The j-j coupling scheme is used for heavy elements (Z > 40), and the L-S coupling scheme is used for the lighter elements. L-S coupling also is called R-S or Russell-Saunders coupling.
