Interpretation of Hydrogen/Deuterium Isotope Effects on NMR Chemical Shifts of [FHF]− Ion Based on Calculations of Nuclear Magnetic Shielding Tensor Surface

Autor:	Dimitri N. Shchepkin, Ilja G. Shenderovich, Peter M. Tolstoy, Gleb S. Denisov, Sona M. Melikova, N. S. Golubev
Rok vydání:	2003
Předmět:	Paramagnetism Nuclear magnetic resonance chemistry Hydrogen Deuterium Proton Chemical shift Difluoride Kinetic isotope effect Fluorine chemistry.chemical_element Physical and Theoretical Chemistry Molecular physics
Zdroj:	Zeitschrift für Physikalische Chemie. 217:1549-1564
ISSN:	2196-7156 0942-9352
DOI:	10.1524/zpch.217.12.1549.20471
Popis:	Using ab initio calculations of 1H, 19F magnetic shielding tensors of hydrogen difluoride ion as the functions of three coordinates of symmetry, an attempt is made to estimate the contributions of different vibrational isotope effects to H/D NMR isotope shifts referred in the literature. It is shown that the contributions of the amplitudes of proton stretching and bending vibrations dominate whereas the contribution of the totally symmetric vibration can be neglected. Different signs of the H/D isotope effects on hydron and fluorine chemical shifts are caused by very strong angle dependence of the fluorine magnetic shielding. The agreement of the calculated and measured values is nearly quantitative. An unusually strong paramagnetic deshielding of hydrogen for the equilibrium geometry of the [FHF]− ion is noted.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::47069cc420ae38f9eff2eb69ec659d76 https://doi.org/10.1524/zpch.217.12.1549.20471 Zobrazit plný text záznamu