University of Oulu

Syed Awais Rouf, Vibe Boel Jakobsen, Jiří Mareš, Nicholai Daugaard Jensen, Christine J. McKenzie, Juha Vaara, Ulla Gro Nielsen, Assignment of solid-state 13C and 1H NMR spectra of paramagnetic Ni(II) acetylacetonate complexes aided by first-principles computations, In Solid State Nuclear Magnetic Resonance, Volume 87, 2017, Pages 29-37, ISSN 0926-2040,

Assignment of solid-state ¹³C and ¹H NMR spectra of paramagnetic Ni(II) acetylacetonate complexes aided by first-principles computations

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Author: Rouf, Syed Awais1; Jakobsen, Vibe Boel2,3; Mareš, Jiří1;
Organizations: 1NMR Research Unit, University of Oulu, P.O. BOX 3000, FIN-90014 Oulu, Finland
2Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, 5230 Odense M, Denmark
3School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 9.4 MB)
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Language: English
Published: Elsevier, 2017
Publish Date: 2019-07-17


Recent advances in computational methodology allowed for first-principles calculations of the nuclear shielding tensor for a series of paramagnetic nickel(II) acetylacetonate complexes, [Ni(acac)₂L₂] with L = H₂O, D₂O, NH₃, ND₃, and PMe₂Ph have provided detailed insight into the origin of the paramagnetic contributions to the total shift tensor. This was employed for the assignment of the solid-state ¹,²H and ¹³C MAS NMR spectra of these compounds. The two major contributions to the isotropic shifts are by orbital (diamagnetic-like) and contact mechanism. The orbital shielding, contact, as well as dipolar terms all contribute to the anisotropic component. The calculations suggest reassignment of the ¹³C methyl and carbonyl resonances in the acac ligand [Inorg. Chem. 53, 2014, 399] leading to isotropic paramagnetic shifts of δ(¹³C) ≈ 800–1100 ppm and ≈180–300 ppm for ¹³C for the methyl and carbonyl carbons located three and two bonds away from the paramagnetic Ni(II) ion, respectively. Assignment using three different empirical correlations, i.e., paramagnetic shifts, shift anisotropy, and relaxation (T₁) were ambiguous, however the latter two support the computational results. Thus, solid-state NMR spectroscopy in combination with modern quantum-chemical calculations of paramagnetic shifts constitutes a promising tool for structural investigations of metal complexes and materials.

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Series: Solid state nuclear magnetic resonance
ISSN: 0926-2040
ISSN-E: 1527-3326
ISSN-L: 0926-2040
Volume: 87
Pages: 29 - 37
DOI: 10.1016/j.ssnmr.2017.07.003
Type of Publication: A1 Journal article – refereed
Field of Science: 114 Physical sciences
Funding: The authors are grateful for financial support from the Villum Foundation via the “Villum Young Investigator Program” grant VKR022364 (UGN, VBJ, NDJ, and SSNMR equipment) and 600 MHz NMR (Villum Center for Bioanalytical Services). The research leading to these results has received funding from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Program FP7 (2007–2013) under REA grant agreement no. 317127 (SAR, JV) and the Academy of Finland projects 258565 and 296292 (SAR, JM, JV).
EU Grant Number: (317127) PNMR - Pushing the Envelope of Nuclear Magnetic Resonance Spectroscopy for Paramagnetic Systems. A Combined Experimental and Theoretical Approach
Academy of Finland Grant Number: 258565
Detailed Information: 258565 (Academy of Finland Funding decision)
296292 (Academy of Finland Funding decision)
Copyright information: © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license