University of Oulu

Mareš, J., Vaara, J. (2018) Ab initio paramagnetic NMR shifts via point-dipole approximation in a large magnetic-anisotropy Co(ii) complex. Physical Chemistry Chemical Physics, 20 (35), 22547-22555. doi:10.1039/C8CP04123G

Ab initio paramagnetic NMR shifts via point-dipole approximation in a large magnetic-anisotropy Co(II) complex

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Author: Mareš, Jiří1; Vaara, Juha1
Organizations: 1NMR Research Unit, University of Oulu
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3.7 MB)
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Language: English
Published: Royal Society of Chemistry, 2018
Publish Date: 2018-09-12


Transition metal complexes can possess a large magnetic susceptibility anisotropy, facilitating applications such as paramagnetic tags or shift agents in nuclear magnetic resonance (NMR) spectroscopy. Due to its g-shift and zero-field splitting (ZFS) we demonstrate on a Co(II) clathrochelate with an aliphatic 16-carbon chain, a modern approach for ab initio calculation of paramagnetic susceptibility. Due to its large anisotropy, large linear dimension but relatively low number of atoms, the chosen complex is especially well-suited for testing the long-range point-dipole approximation (PDA) for the pseudocontact shifts (PCSs) of paramagnetic NMR. A static structure of the complex is used to compare the limiting long-distance PDA with full first-principles quantum-mechanical calculation. A non-symmetric formula for the magnetic susceptibility tensor is necessary to be consistent with the latter. Comparison with experimental shifts is performed by conformational averaging over the chain dynamics using Monte Carlo simulation. We observe satisfactory accuracy from the rudimentary simulation and, more importantly, demonstrate the fast applicability of the ab initio PDA.

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Series: PCCP. Physical chemistry chemical physics
ISSN: 1463-9076
ISSN-E: 1463-9084
ISSN-L: 1463-9076
Volume: 20
Issue: 35
Pages: 22547 - 22555
DOI: 10.1039/C8CP04123G
Type of Publication: A1 Journal article – refereed
Field of Science: 114 Physical sciences
116 Chemical sciences
Funding: The authors thank to Finnish Cultural Foundation (JM), Academy of Finland (grant no. 296292) and University of Oulu (Kvantum Institute) for financial support, as well as CSC-IT Center for Science (Espoo, Finland) and Finnish Grid and Cloud Infrastructure (persistent identifier urn:nbn:fi:research-infras-2016072533) for computational resources.
Academy of Finland Grant Number: 296292
Detailed Information: 296292 (Academy of Finland Funding decision)
Copyright information: This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.