Related Experiment Video
Updated: Mar 29, 2026
14:44
Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
Published on: December 16, 2013
10.2K
A General Method for Extracting Individual Coupling Constants from Crowded (1)H NMR Spectra
Davy Sinnaeve1,2, Mohammadali Foroozandeh3, Mathias Nilsson3
1School of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK. Davy.Sinnaeve@UGent.be.
Angewandte Chemie (International Ed. in English)
|December 5, 2015
Summary
A new method called PSYCHEDELIC suppresses proton-proton couplings in NMR spectra. This allows for clearer analysis of structural and conformational information, approaching theoretical resolution limits.
Area of Science:
- Nuclear Magnetic Resonance (NMR) Spectroscopy
- Structural Chemistry
Background:
- Proton-proton (1H-1H) couplings offer valuable structural insights.
- Complex spectra and signal overlap in crowded NMR spectra hinder accurate coupling measurement.
Purpose of the Study:
- To introduce PSYCHEDELIC, a novel 2D J-resolved NMR method.
- To enable high-resolution analysis of (1H-1H) couplings by suppressing unwanted signals.
Main Methods:
- Development of a general 2D J-resolved NMR technique.
- Suppression of all homonuclear couplings in the F2 dimension.
- Presentation of selected couplings as doublets in the F1 dimension.
Main Results:
- PSYCHEDELIC achieves near-natural linewidth resolution for (1H-1H) couplings.
- Spectra exhibit only chemical shifts in F2, simplifying analysis.
- The method maintains high sensitivity and spectral purity, similar to PSYCHE experiments.
Conclusions:
- PSYCHEDELIC provides a robust approach for resolving (1H-1H) couplings.
- Enables detailed structural, conformational, and stereochemical analyses.
- Offers a significant advancement over existing methods for complex NMR spectra.
Related Concept Videos
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
1.7K
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...
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...
1.7K
01:17Spin–Spin Coupling: One-Bond Coupling
1.6K
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,...
1.6K
01:08Spin–Spin Coupling Constant: Overview
1.6K
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...
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...
1.6K
01:13¹H NMR: Complex Splitting
2.1K
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
2.1K
01:04¹³C NMR: ¹H–¹³C Decoupling
2.1K
The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
2.1K
01:27¹H NMR: Long-Range Coupling
2.9K
The coupling interactions of nuclei across four or more bonds are usually weak, with J values less than 1 Hz. While these are usually not observed in spectra, the presence of multiple bonds along the coupling pathway can result in observable long-range coupling.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene...
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene...
2.9K