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@article{1423446,
author = {Jeremias, Lukáš and Novotný, Jan and Repisky, Michal and Komorovsky, Stanislav and Marek, Radek},
article_number = {15},
doi = {http://dx.doi.org/10.1021/acs.inorgchem.8b00073},
keywords = {NMR chemical shift; paramagnetic NMR; hyperfine interaction; Fermi-contact; relativistic DFT; ruthenium},
language = {eng},
issn = {0020-1669},
journal = {Inorganic Chemistry},
title = {Interplay of Through-Bond Hyperfine and Substituent Effects on the NMR Chemical Shifts in Ru(III) Complexes},
url = {http://dx.doi.org/10.1021/acs.inorgchem.8b00073},
volume = {57},
year = {2018}
}
TY - JOUR
ID - 1423446
AU - Jeremias, Lukáš - Novotný, Jan - Repisky, Michal - Komorovsky, Stanislav - Marek, Radek
PY - 2018
TI - Interplay of Through-Bond Hyperfine and Substituent Effects on the NMR Chemical Shifts in Ru(III) Complexes
JF - Inorganic Chemistry
VL - 57
IS - 15
SP - 8748-8759
EP - 8748-8759
PB - American Chemical Society
SN - 00201669
KW - NMR chemical shift
KW - paramagnetic NMR
KW - hyperfine interaction
KW - Fermi-contact
KW - relativistic DFT
KW - ruthenium
UR - http://dx.doi.org/10.1021/acs.inorgchem.8b00073
L2 - http://dx.doi.org/10.1021/acs.inorgchem.8b00073
N2 - The links between the molecular structure and nuclear magnetic resonance (NMR) parameters of paramagnetic transition-metal complexes are still relatively unexplored. This applies particularly to the contact term of the hyperfine contribution to the NMR chemical shift. We report combining experimental NMR with relativistic density functional theory (DFT) to study a series of Ru(III) complexes with 2-substituted beta-diketones. A series of complexes with systematically varied substituents was synthesized and analyzed using 1H and 13C NMR spectroscopy. The NMR spectra recorded at several temperatures were used to construct Curie plots and estimate the temperature-independent (orbital) and temperature-dependent (hyperfine) contributions to the NMR shift. Relativistic DFT calculations of electron paramagnetic resonance and NMR parameters were performed to interpret the experimental observations. The effects of individual factors such as basis set, density functional, exact-exchange admixture, and relativity are analyzed and discussed. Based on the calibration study in this work, the fully relativistic Dirac–Kohn–Sham (DKS) method, the GIAO approach (orbital shift), the PBE0 functional with the triple-zeta valence basis sets, and the polarizable continuum model for describing solvent effects were selected to calculate the NMR parameters. The hyperfine contribution to the total paramagnetic NMR (pNMR) chemical shift is shown to be governed by the Fermi-contact (FC) term, and the substituent effect (H vs Br) on the through-bond FC shifts is analyzed, interpreted, and discussed in terms of spin-density distribution, atomic spin populations, and molecular-orbital theory. In contrast to the closed-shell systems of Rh(III), the presence of a single unpaired electron in the open-shell Ru(III) analogs significantly alters the NMR resonances of the ligand atoms distant from the metal center in synergy with the substituent effect.
ER -
JEREMIAS, Lukáš, Jan NOVOTNÝ, Michal REPISKY, Stanislav KOMOROVSKY a Radek MAREK. Interplay of Through-Bond Hyperfine and Substituent Effects on the NMR Chemical Shifts in Ru(III) Complexes. \textit{Inorganic Chemistry}. American Chemical Society, 2018, roč.~57, č.~15, s.~8748-8759. ISSN~0020-1669. Dostupné z: https://dx.doi.org/10.1021/acs.inorgchem.8b00073.
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