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DFT Study of the NMR Properties of Xenon in Covalent Compounds and van der Waals Complexes—Implications for the Use of 129 Xe as a Molecular Probe
Author(s) -
Bagno Alessandro,
Saielli Giacomo
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200390168
Subject(s) - chemistry , van der waals force , xenon , coupling constant , fermi contact interaction , paramagnetism , van der waals radius , van der waals strain , diamagnetism , relativistic quantum chemistry , atomic physics , chemical shift , spin–orbit interaction , covalent bond , molecular physics , hyperfine structure , molecule , physics , condensed matter physics , quantum mechanics , magnetic field , organic chemistry
The NMR properties (chemical shift and spin–spin coupling constants) of 129 Xe in covalent compounds and weakly bound complexes have been investigated by DFT methods including relativistic effects. For covalent species, a good agreement between experimental and calculated results is achieved without scalar relativistic effects, but their inclusion (with a triple‐ ζ , double‐polarization basis set) leads to some improvement in the quality of the correlation. The spin–orbit coupling term has a significant effect on the shielding constant, but makes a small contribution to the chemical shift. Coupling constants contain substantial contributions from the Fermi contact and paramagnetic spin–orbit terms; unlike light nuclei the spin–dipole term is also large, whereas the diamagnetic spin–orbit term is negligible. For van der Waals dimers, the dependence of the xenon chemical shift and anisotropy is calculated as a function of the distance. Small (<1 Hz) but non‐negligible through‐space coupling constants between 129 Xe and 13 C or 1 H are predicted. Much larger couplings, of the order of few Hz, are calculated between xenon and 17 O in a model silicate residue.