Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Spin–Spin Coupling: One-Bond Coupling

Spin–Spin Coupling: One-Bond Coupling

Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...

Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)

Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)

Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...

Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)

Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)

Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive.
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...

NMR Spectroscopy: Spin–Spin Coupling

NMR Spectroscopy: Spin–Spin Coupling

The spin state of an NMR-active nucleus can have a slight effect on its immediate electronic environment. This effect propagates through the intervening bonds and affects the electronic environments of NMR-active nuclei up to three bonds away; occasionally, even farther. This phenomenon is called spin–spin coupling or J-coupling. Coupling interactions are mutual and result in small changes in the absorption frequencies of both nuclei involved. While nuclei of the same element are involved...

Spin–Spin Coupling Constant: Overview

Spin–Spin Coupling Constant: Overview

In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...

G-protein Coupled Receptors

G-protein Coupled Receptors

G-protein coupled receptors are ligand binding receptors that indirectly affect changes in the cell. The actual receptor is a single polypeptide that transverses the cell membrane seven times creating intracellular and extracellular loops. The extracellular loops create a ligand specific pocket which binds to neurotransmitters or hormones. The intracellular loops holds onto the G-protein.

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Quantum Zeno Effect Permits Magnetosensitivity in Lipid Peroxidation despite Fluctuating Inter-Radical Coupling.

JACS Au·2026

Same author

Spin Relaxation Does Not Preclude Magnetic Field Effects on Lipid Autoxidation.

ACS central science·2026

Same author

Engineering the uncontrollable: Steering noisy spin-correlated radical-pairs with coherent and incoherent control.

The Journal of chemical physics·2026

Same author

Weak Radiofrequency Field Effects on Biological Systems Mediated through the Radical Pair Mechanism.

Chemical reviews·2025

Same author

Electron hopping in cryptochrome: Implications for radical pair magnetoreception and the role of the fourth tryptophan.

The Journal of chemical physics·2025

Same author

Fundamental aspects of Aharonov-Bohm quantum machines: thermoelectric heat engines and diodes.

Journal of physics. Condensed matter : an Institute of Physics journal·2025

Search research articles

Related Experiment Video

Updated: Feb 5, 2026

High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy

High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy

Published on: October 9, 2020

Magnetosensitivity in Dipolarly Coupled Three-Spin Systems.

Robert H Keens¹, Salil Bedkihal¹, Daniel R Kattnig¹

¹Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, Devon, EX4 4QD, United Kingdom.

Physical Review Letters

|September 20, 2018

Summary

Researchers found that magnetic field effects on chemical reactions do not require hyperfine interactions. Three-radical systems using dipolar interactions show sensitivity to weak magnetic fields, opening new avenues for quantum sensing and spintronics.

More Related Videos

The Use of Chemostats in Microbial Systems Biology

The Use of Chemostats in Microbial Systems Biology

Published on: October 14, 2013

Demonstration of Spin-Multiplexed and Direction-Multiplexed All-Dielectric Visible Metaholograms

Demonstration of Spin-Multiplexed and Direction-Multiplexed All-Dielectric Visible Metaholograms

Published on: September 25, 2020

Related Experiment Videos

Last Updated: Feb 5, 2026

High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy

High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy

Published on: October 9, 2020

The Use of Chemostats in Microbial Systems Biology

The Use of Chemostats in Microbial Systems Biology

Published on: October 14, 2013

Demonstration of Spin-Multiplexed and Direction-Multiplexed All-Dielectric Visible Metaholograms

Demonstration of Spin-Multiplexed and Direction-Multiplexed All-Dielectric Visible Metaholograms

Published on: September 25, 2020

Area of Science:

Chemical Physics
Quantum Mechanics
Biophysics

Background:

The radical pair mechanism explains magnetosensitivity in chemical reactions via hyperfine interactions.
This mechanism relies on electron spin state mixing to influence reaction yields through magnetic field effects (MFEs).

Purpose of the Study:

To investigate alternative mechanisms for magnetic field sensitivity in chemical reactions beyond hyperfine interactions.
To explore the role of three-radical systems and dipolar interactions in mediating MFEs.

Main Methods:

Theoretical modeling of spin dynamics in three-radical systems.
Analysis of the influence of symmetries, energy level crossings, and exchange interactions on MFEs.
Investigating dipolar interactions as an alternative to hyperfine interactions for MFEs.

Main Results:

Demonstrated that dipolar interactions in three-radical systems can induce MFEs without hyperfine interactions.
Observed directional sensitivity to magnetic fields weaker than the geomagnetic field.
Identified tunable spikes in reaction yield as a function of magnetic field intensity.

Conclusions:

The hyperfine interaction is not essential for radical reactions to be sensitive to weak magnetic fields.
Dipolar interactions in three-radical systems offer a novel pathway for MFEs, with potential applications in quantum sensing and spintronics.
These findings advance the understanding of biological magnetoreception and solid-state quantum information processing.