Towards accurate predictions of proton NMR parameters in molecular solids

Dracinsky, Martin; Vícha, Jan; Bártová, Kateřina; Hodgkinson, Paul

Abstract

The factors contributing to the accuracy of quantum‐chemical calculations of proton NMR chemical shifts in molecular solids are systematically investigated. Proton chemical shifts of six solid amino acids with hydrogen atoms in various bonding environments (CH, CH 2 , CH 3 , OH, SH and NH 3 ) were determined experimentally using ultra‐fast magic‐angle spinning and proton‐detected 2D NMR experiments. The standard DFT method commonly used for the calculations of NMR parameters of solids is shown to provide chemical shifts that deviate from experiment by up to 1.5 ppm. The effects of the computational level (hybrid DFT functional, coupled‐cluster calculation, inclusion of relativistic spin‐orbit coupling) are thoroughly discussed. The effect of molecular dynamics and nuclear quantum effects are investigated using path‐integral molecular dynamics (PIMD) simulations. It is demonstrated that the accuracy of the calculated proton chemical shifts is significantly better when these effects are included in the calculations.

Citation

Dracinsky, M., Vícha, J., Bártová, K., & Hodgkinson, P. (2020). Towards accurate predictions of proton NMR parameters in molecular solids. ChemPhysChem, 21(18), 2075-2083. https://doi.org/10.1002/cphc.202000629

• Journal Article Type: Article
• Acceptance Date: Jul 20, 2020
• Online Publication Date: Aug 26, 2020
• Publication Date: 2020
• Deposit Date: Jul 21, 2020
• Publicly Available Date: Aug 26, 2021
• Journal: ChemPhysChem
• Print ISSN: 1439-4235
• Electronic ISSN: 1439-7641
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 21
• Issue: 18
• Pages: 2075-2083
• DOI: https://doi.org/10.1002/cphc.202000629
• Public URL: https://durham-repository.worktribe.com/output/1260410