Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Spin–Spin Coupling: One-Bond Coupling01:17

Spin–Spin Coupling: One-Bond Coupling

950
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,...
950
Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)01:20

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

983
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...
983
Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)01:22

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

1.0K
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...
1.0K
Spin–Spin Coupling Constant: Overview01:08

Spin–Spin Coupling Constant: Overview

899
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...
899
NMR Spectroscopy: Spin–Spin Coupling01:08

NMR Spectroscopy: Spin–Spin Coupling

1.3K
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...
1.3K
¹H NMR: Interpreting Distorted and Overlapping Signals01:02

¹H NMR: Interpreting Distorted and Overlapping Signals

1.0K
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
1.0K

You might also read

Related Articles

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

Sort by
Same author

One-Pot, One-Step Mn-bis(imino)pyridine Complexes through Sonochemistry.

Inorganic chemistry·2026
Same author

Effectiveness of a multidisciplinary "crisis checklist" on nursing performance during intraoperative cardiac arrest: A simulation-based study.

Scientific reports·2026
Same author

Spin-orbit-resolved strong-field ionization from real-time relativistic dynamics.

The Journal of chemical physics·2026
Same author

Time-Dependent Relativistic Two-Component Equation-of-Motion Coupled Cluster for Open-Shell Systems: TD-EA/IP-EOMCC.

The journal of physical chemistry. A·2026
Same author

NDUFA4 Deletion Upregulates VDAC1 to Promote Mitochondrial Damage, Endoplasmic Reticulum Expansion, and Neuronal Apoptosis.

Human mutation·2026
Same author

Unlocking Random Poly(ether-ester-carbonate) Polyols with Ultralow Molecular Weight.

ACS macro letters·2026

Related Experiment Video

Updated: Jun 14, 2025

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
09:00

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser

Published on: June 28, 2018

9.9K

Spin-Vibronic Coupling Enhanced Intersystem Crossing beyond El-Sayed Restrictions.

Can Liao1, Cecily Rosenbaum1, Alexis M Glaudin1

  • 1Department of Chemistry, University of Washington, Seattle, Washington 98195, United States.

Journal of the American Chemical Society
|June 13, 2025
PubMed
Summary

This study reveals how symmetry, not heavy atoms, can drive rapid intersystem crossing in organic molecules. This discovery offers new pathways for designing efficient heavy-atom-free photochemical systems.

More Related Videos

Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
08:22

Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization

Published on: August 6, 2018

6.8K
High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
10:40

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy

Published on: June 28, 2016

7.5K

Related Experiment Videos

Last Updated: Jun 14, 2025

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
09:00

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser

Published on: June 28, 2018

9.9K
Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
08:22

Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization

Published on: August 6, 2018

6.8K
High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
10:40

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy

Published on: June 28, 2016

7.5K

Area of Science:

  • Photochemistry
  • Quantum Chemistry
  • Materials Science

Background:

  • Intersystem crossing (ISC) is vital in photochemistry, typically driven by spin-orbit coupling.
  • Designing molecules to control ISC rates is a key research area.
  • Heavy atoms are conventionally used to enhance spin-orbit coupling for efficient ISC.

Purpose of the Study:

  • To investigate the mechanisms behind unusually rapid ISC in organic molecules lacking heavy atoms.
  • To explore the role of symmetry-perturbation in enabling ISC.
  • To understand ISC in dibutylaniline thiosquaraine's lowest excited states (S(nπ*) and T(ππ*)).

Main Methods:

  • Computational analysis of intersystem crossing rates.
  • Investigation of spin-vibronic mechanisms.
  • Focus on symmetry-perturbation effects.

Main Results:

  • Identified symmetry-perturbation as the primary driver for ISC in the studied system.
  • Demonstrated that ISC occurs via a symmetry-perturbing spin-vibronic mechanism.
  • Showed that El-Sayed restrictions are not the dominant factor in this case.

Conclusions:

  • Symmetry considerations are crucial for designing efficient heavy-atom-free molecular systems for ISC.
  • This work provides new insights for chemists and engineers developing novel photochemical materials.
  • The findings enable the rational design of molecules with tunable ISC properties.