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Updated: May 19, 2026
14:55
Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
NMR landscapes for chemical shift prediction
Katharine W Moore1, Richard Li, Istvan Pelczer
1Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States.
The Journal of Physical Chemistry. A
|August 21, 2012
Summary
NMRscape predicts nuclear magnetic resonance (NMR) chemical shifts by mapping relationships between chemical shifts and molecular structures. This tool offers higher accuracy than existing methods, aiding organic molecule structure elucidation.
Area of Science:
- Organic Chemistry
- Computational Chemistry
- Spectroscopy
Background:
- Predicting NMR chemical shifts is crucial for determining organic molecule structures.
- Understanding the influence of structural, electronic, and environmental factors on chemical shifts is complex.
Purpose of the Study:
- Introduce NMRscape, a novel tool for analyzing NMR chemical shift correlations.
- Visualize the relationship between chemical shift values and molecular moieties on a scaffold.
Main Methods:
- NMRscape utilizes a list of bonded chemical moieties without chemometric descriptors.
- Constructs a chemical shift landscape based on fundamental physical principles.
Main Results:
- NMRscape accurately predicts carbon-13 ((13)C) chemical shifts, outperforming substituent chemical shift (SCS) increment, hierarchical organization of spherical environments (HOSE), and neural network (NN) methods.
- NMR landscapes validated known empirical rules and revealed new structure-chemical shift relationships.
Conclusions:
- NMRscape is a credible tool for chemical shift prediction and analysis.
- The tool enhances understanding of factors influencing NMR chemical shifts and aids in structure elucidation.
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The position of the absorption signal of a sample is reported relative to the position of the signal of tetramethylsilane (TMS), which is added as an internal reference while recording spectra. The difference between the absorption frequencies of the sample and TMS (in Hz) is divided by the spectrometer operating frequency (in MHz) to obtain a dimensionless quantity called the chemical shift. It is reported on the δ (delta) scale and expressed in parts per million.
For instance, the proton...
For instance, the proton...
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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 slanted or...
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