Improving the accuracy of 31P NMR chemical shift calculations by use of scaling methods

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.

31P Nuclear Magnetic Resonance Spectroscopy for Monitoring Organic Reactions and Organic Compounds

31P NMR spectroscopy is a consolidated tool for the characterization of organophosphorus compounds and, more recently, for reaction monitoring. The evolution of organic synthesis, mainly due to the combination of elaborated building blocks with enabling technologies, generated great challenges to understand and to optimize the synthetic methodologies. In this sense, 31P NMR experiments also became a routine technique for reaction monitoring, accessing products and side products yields, chiral recognition, kinetic data, intermediates, as well as basic organic parameters, such as acid-base and hydrogen-bonding. This review deals with these aspects demonstrating the essential role of the 31P NMR spectroscopy. The recent publications (the last ten years) will be explored, discussing the experiments of 31P NMR and the strategies accomplished to detect and/or quantify distinct organophosphorus molecules, approaching reaction mechanism, stability, stereochemistry, and the utility as a probe.