Experimental and Theoretical Evidence of Spin‐Orbit Heavy Atom on the Light Atom 1H NMR Chemical Shifts Induced through H⋅⋅⋅I− Hydrogen Bond

0532381 - ÚOCHB 2021 RIV DE eng J - Journal Article
Vícha, Jan - Švec, P. - Růžičková, Z. - Samsonov, M. A. - Bártová, Kateřina - Růžička, A. - Straka, Michal - Dračínský, Martin
Experimental and Theoretical Evidence of Spin‐Orbit Heavy Atom on the Light Atom 1H NMR Chemical Shifts Induced through H⋅⋅⋅I− Hydrogen Bond.
Chemistry - A European Journal. Roč. 26, č. 40 (2020), s. 8698-8702. ISSN 0947-6539. E-ISSN 1521-3765
R&D Projects: GA ČR(CZ) GA20-01472S; GA MŠMT(CZ) LTAUSA19148
Institutional support: RVO:61388963
Keywords : DFT calculations * hydrogen bonding * NMR spectroscopy * relativistic effects * spin-orbit coupling
OECD category: Organic chemistry
Impact factor: 5.236, year: 2020
Method of publishing: Limited access
https://doi.org/10.1002/chem.202001532

Spin‐orbit (SO) heavy‐atom on the light‐atom (SO‐HALA) effect is the largest relativistic effect caused by a heavy atom on its light‐atom neighbors, leading, for example, to unexpected NMR chemical shifts of 1H, 13C, and 15N nuclei. In this study, a combined experimental and theoretical evidence for the SO‐HALA effect transmitted through hydrogen bond is presented. Solid‐state NMR data for a series of 4‐dimethylaminopyridine salts containing I−, Br− and Cl− counter ions were obtained experimentally and by theoretical calculations. A comparison of the experimental chemical shifts with those calculated by a standard DFT methodology without the SO contribution to the chemical shifts revealed a remarkable error of the calculated proton chemical shift of a hydrogen atom that is in close contact with the iodide anion. The addition of the relativistic SO correction in the calculations significantly improves overall agreement with the experiment and confirms the propagation of the SO‐HALA effect through hydrogen bonds.
Permanent Link: http://hdl.handle.net/11104/0310883