Nucleus Independent Chemical Shift (NICS) at Small Distances from the Molecular Plane: The Effect of Electron Density

• DOI: 10.1002/cphc.202300080
• Publication Date: 2023-02-14T06:40:26Z
• Authors: Amnon Stanger

When close to the molecular plane, behavior of nucleus independent chemical shift (NICS) as a function distance from plane deviates its at larger distances. By using dense grid NICS-probes (BQs) it is shown that, when maximal (absolute) NICS values are obtained above atoms. These maxima move towards center elevated until maximum and stay there further elevated. It that this result current density, which influenced by electron according Biot-Savart law, which, in turn, causes induced magnetic field measured NICS. thus concluded if aromaticity studied, calculations should be carried out large enough so only π-ring affects At distances ≥2 Å, NICS(r)π,zz =A+B*Cr . Using non-linear correlation for obtaining A, B C extrapolate NICS(1)π,zz NICS(1.7)π,zz recommended measures aromaticity.