The Scope of the Applicability of Non‐relativistic DFT Calculations of NMR Chemical Shifts in Pyridine‐Metal Complexes for Applied Applications

• Published in: Chemphyschem 2024-04, Vol.25 (7), p.e202300986-n/a
• Main Author: Shenderovich, Ilya G.
• Format: Article
• Language: English
• Subjects: Chemical equilibrium; Coordination compounds; Density functional calculations; Heavy metals; NMR spectroscopy; Noncovalent interactions; Periodic table; Pyridines; Relativistic effects; Solid-state structures; System effectiveness; Tensors; Transition metals
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.202300986

Heavy metals are toxic, but it is impossible to stop using them. Considering the variety of molecular systems in which they can be present, the multicomponent nature and disorder of the structure of such systems, one of the most effective methods for studying them is NMR spectroscopy. This determines the need to calculate NMR chemical shifts for expected model systems. For elements beyond the third row of the periodic table, corrections for relativistic effects are necessary when calculating NMR parameters. Such corrections may be necessary even for light atoms due to the shielding effect of a neighboring heavy atom. This work examines the extent to which non‐relativistic DFT calculations are able to reproduce experimental 15N and 113Cd NMR chemical shift tensors in pyridine‐metal coordination complexes. It is shown that while for the calculation of 15N NMR chemical shift tensors there is no real need to consider relativistic corrections, for 113Cd, on the contrary, none of the tested calculation methods could reproduce the experimentally obtained tensor to any extent correctly. Is there a royal road to NMR chemical shift calculations? Specifically, can relativistic effects be neglected when estimating NMR parameters with an accuracy sufficient for applied purposes? This question is answered based on the study of the 15N and 113Cd NMR chemical shift tensors of pyridine‐metal coordination complexes.