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Assessment of Density Functionals for Predicting One-Bond Carbon-Hydrogen NMR Spin-Spin Coupling Constants
Sergey N Maximoff1, Juan E Peralta1, Verónica Barone1
1Department of Chemistry, Rice University, Houston, Texas 77005-1892.
Journal of Chemical Theory and Computation
|December 8, 2015
Summary
This study benchmarks 20 approximate density functionals for calculating carbon-hydrogen NMR spin-spin coupling constants. Generalized gradient approximations demonstrated the best performance for these crucial molecular parameters.
Area of Science:
- Computational Chemistry
- Quantum Chemistry
- Nuclear Magnetic Resonance Spectroscopy
Background:
- Nuclear Magnetic Resonance (NMR) spin-spin coupling constants (SSCCs) provide valuable structural information.
- Accurate calculation of SSCCs, particularly one-bond carbon-hydrogen (¹JCH) couplings, is essential for molecular characterization.
- Approximate density functional theory (DFT) methods are widely used but require careful benchmarking for specific properties.
Purpose of the Study:
- To evaluate the performance of 20 diverse approximate density functionals in calculating one-bond carbon-hydrogen NMR SSCCs.
- To identify the most accurate functional class for predicting ¹JCH couplings across a range of molecular structures.
- To provide guidance for selecting appropriate computational methods in NMR spectroscopy.
Main Methods:
- Benchmarking of 20 approximate density functionals, including local-spin density approximation, generalized gradient approximations (GGAs), and hybrid functionals.
- Calculation of one-bond carbon-hydrogen NMR SSCCs for a test set of 72 diverse molecules.
- Comparison of calculated SSCCs against 96 experimentally measured ¹JCH coupling constants.
Main Results:
- The study systematically assessed the accuracy of various density functionals for ¹JCH SSCC calculations.
- Generalized gradient approximations (GGAs) were found to provide the best performance among the tested functionals for one-bond C-H couplings.
- The performance varied across different functional types, highlighting the importance of method selection.
Conclusions:
- Approximate density functionals, particularly GGAs, are suitable for accurate prediction of one-bond carbon-hydrogen NMR SSCCs.
- The choice of density functional significantly impacts the accuracy of calculated ¹JCH couplings.
- This work offers valuable insights for computational chemists utilizing NMR spectroscopy for molecular structure determination.
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