Going beyond the routine consideration of solvent effects on 31P NMR shielding constants: a meticulous basis set study and new aug-pecS-n (n = 1 and 2) basis sets for phosphorus atoms†

In this paper, we demonstrate that the accuracy of calculated solvent corrections to ³¹P NMR shielding constants of various phosphorus-containing molecules significantly depends on the basis set used. The highly positive role played by diffuse functions was revealed not only for the solvent corrections but also for phosphorus NMR shielding constants of anions. Considering this matter, the augmentation in shift-oriented pecS-n (n = 1 and 2) basis sets for phosphorus atoms with diffuse functions was carried out using the property-energy consistent (PEC) method with isotropic dipole polarizability used as the main target property, which is the first example of such augmentation of basis sets. Alongside other augmented basis sets of different types and qualities, the new aug-pecS-n (n = 1 and 2) basis sets were shown to significantly improve the accuracy of solvent corrections to the ³¹P NMR shielding constants of neutral molecules and phosphorus shielding constants of anions compared with their non-augmented analogs. Finally, comparison with available experimental data corroborated our theoretical findings.