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29 lis 2023 · Theoretical prediction of NMR shielding tensor, as well as indirect spin–spin coupling could be highly accurate in case of small to medium size molecules, mainly in case of high-level coupled cluster methods, applying large and specially designed basis sets.
2 cze 2024 · Gas phase studies permit the withdrawal of intermolecular contributions from shielding and obtaining the magnetic shielding data in isolated molecules. The shielding determination in molecules is possible using at least three methods delivering the reference shielding standards for selected nuclei.
15 gru 2020 · In summary, our results show that all considered explicit and implicit solvent models provide the correct deshielding tendency of the gas-water 15 N NMR shift of FMA. Also the models that lack inclusion of explicit solvent hydrogen bonds underestimate the total gas-water 15 N NMR shift of FMA.
23 lis 2020 · GIAO NMR calculations of shielding constants were conducted in THF with mPW1PW91, PBE0 and B3LYP density functionals, combined with 6-311+G(2d,p), cc-pVDZ and cc-pVTZ basis sets. Fitted empirical scaling factors from linear plots of theoretical vs. experimental boron chemical shifts were derived.
1 cze 2023 · The effects caused by the interaction with graphene-like layers on the 1 H NMR spectra of water molecules adsorbed onto porous carbon materials were investigated by a combination of shielding calculations using density functional theory (DFT) and 1 H NMR experiments.
29 cze 2024 · All the investigated shielding parameters depend on intermolecular interactions, and the dependence of 13 C shielding is much more marked. In contrast, the indirect spin–spin couplings in 13 C 2 H 6 and 13 C 2 H 4 molecules are almost independent of solvent molecules.
28 kwi 2022 · Multinuclear NMR studies of the gaseous mixtures that involve volatile compounds and 3 He atoms are featured in this review. The precise analyses of 3 He and other nuclei resonance frequencies show linear dependencies on gas density.
