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

Abstract

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.

Keywords: Density functional calculations; NMR spectroscopy; Noncovalent interactions; Solid-state structures; Transition metals.