Related Experiment Video
Updated: May 15, 2026
10:40
High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
Published on: June 28, 2016
Spatially encoded ultrafast high-resolution 2D homonuclear correlation spectroscopy in inhomogeneous fields
Zhiyong Zhang1, Hao Chen, Can Wu
1Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Fujian, China.
Journal of Magnetic Resonance (San Diego, Calif. : 1997)
|December 25, 2012
Summary
New pulse sequences enable ultrafast, high-resolution 2D NMR correlation spectroscopy (COSY and TOCSY) even in inhomogeneous magnetic fields. This overcomes limitations of long acquisition times and poor resolution in challenging environments.
Area of Science:
- Nuclear Magnetic Resonance (NMR) Spectroscopy
- Analytical Chemistry
- Spectroscopy
Background:
- Two-dimensional (2D) NMR spectroscopy is vital but faces challenges with resolution in inhomogeneous fields and long acquisition times.
- Conventional methods struggle to provide high-resolution 2D spectra, limiting their applicability in certain conditions.
Purpose of the Study:
- To develop novel pulse sequences for ultrafast, high-resolution 2D correlation spectroscopy (COSY and TOCSY).
- To address the limitations of spectral resolution and acquisition time in inhomogeneous magnetic fields.
Main Methods:
- Proposed two new pulse sequences based on tracking precession frequency differences of coupled spins.
- Utilized mathematical manipulations to reduce spectral width in the indirect dimension for improved resolution.
- Performed theoretical analysis and experimental verification.
Main Results:
- Demonstrated the ability to achieve high-resolution 2D COSY and TOCSY spectra in a single scan.
- Confirmed that the proposed sequences yield correct spectra under linear field inhomogeneity.
- Spectral width reduction improved resolution without losing correlative information.
Conclusions:
- The novel pulse sequences effectively overcome the limitations of conventional 2D NMR in inhomogeneous fields.
- Ultrafast acquisition and high resolution are achievable, expanding the utility of COSY and TOCSY.
- This advancement offers significant potential for rapid and accurate structural elucidation in NMR.
Related Concept Videos
01:162D NMR: Overview of Homonuclear Correlation Techniques
Homonuclear correlation spectroscopy (COSY) is a powerful technique used in Nuclear Magnetic Resonance (NMR) spectroscopy to study the correlations between nuclei of the same type within a molecule. It provides information about scalar couplings between adjacent nuclei, which helps determine connectivity and structural information. There are several COSY variants, each with its unique strengths and experimental parameters.
COSY90 is the standard two-dimensional (2D) COSY experiment that...
COSY90 is the standard two-dimensional (2D) COSY experiment that...
01:062D NMR: Homonuclear Correlation Spectroscopy (COSY)
Homonuclear correlation spectroscopy, or COSY, is a 2-dimensional NMR technique that provides information about coupled protons. Typically, the geminal and vicinal coupling are observed. For example, consider the COSY spectrum of ethyl acetate, where its 1D proton NMR spectrum is plotted along the vertical and horizontal axes with their corresponding chemical shift scale. Three spots on the diagonal corresponding to the three peaks in the 1D proton spectrum are called diagonal peaks. The COSY...
01:182D NMR: Overview of Heteronuclear Correlation Techniques
Heteronuclear correlation spectroscopy is an analytical technique that investigates the coupling between different types of nuclei, often a proton and an X-nucleus, such as carbon-13 or nitrogen-15. This method is commonly used in nuclear magnetic resonance (NMR) spectroscopy to gain insights into complex chemical compounds' structural and compositional aspects. A typical heteronuclear correlation spectrum displays X-nucleus chemical shifts on one axis and a proton spectrum on the other axis.
01:192D NMR: Heteronuclear Single-Quantum Correlation Spectroscopy (HSQC)
Heteronuclear single-quantum correlation spectroscopy (HSQC) is a 2D NMR technique that reveals one-bond correlations between hydrogen and a heteronucleus. The HSQC experiment is similar to the heteronuclear correlation experiment (HETCOR) but is more sensitive. In the HSQC spectrum, the proton chemical shift is plotted on the horizontal F2 axis, while the 13C chemical shift is plotted on the vertical F1 axis. The corresponding proton and 13C spectra are also shown. The HSQC contour plot does...
01:12Two-Dimensional (2D) NMR: Overview
The 1D NMR spectrum of large and complex molecules like natural products has complicated splitting patterns and overlapping signals, which can be easily interpreted using 2-dimensional (2D) NMR. Unlike 1D NMR, 2D NMR has two frequency axes that provide the coupling information between the nucleus A and nucleus B in a molecule. The process from which 2D spectra are obtained has four steps.
The first step is the preparation period, during which nucleus A is excited with a radiofrequency pulse.
The first step is the preparation period, during which nucleus A is excited with a radiofrequency pulse.
01:08NMR 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 in...