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Title: Ligand NMR Chemical Shift Calculations for Paramagnetic Metal Complexes: 5f 1 vs 5f 2 Actinides

Ligand paramagnetic NMR (pNMR) chemical shifts of the 5f 1 complexes UO 2(CO 3) 3 5- and NpO 2(CO 3) 3 4-, and of the 5f 2 complexes PuO 2(CO 3) 3 4- and (C 5H 5) 3UCH 3 are investigated by wave function theory calculations, using a recently developed sum-over-states approach within complete active space and restricted active space paradigm including spin–orbit (SO) coupling [J. Phys. Chem. Lett. 2015, 20, 2183-2188]. The experimental 13C pNMR shifts of the actinyl tris-carbonate complexes are well reproduced by the calculations. The results are rationalized by visualizing natural spin orbitals (NSOs) and spin-magnetizations generated from the SO wave functions, in comparison with scalar relativistic spin densities. The analysis reveals a complex balance between spin-polarization, spin and orbital magnetization delocalization, and spin-compensation effects due to SO coupling. This balance creates the magnetization due to the electron paramagnetism around the nucleus of interest, and therefore the pNMR effects. The calculated proton pNMR shifts of the (C 5H 5) 3UCH 3 complex are also in good agreement with experimental data. Because of the nonmagnetic ground state of (C 5H 5) 3UCH 3, the 1H pNMR shifts arise mainly from the magnetic coupling contributions between the groundmore » state and low-energy excited states belonging to the 5f manifold, along with the thermal population of degenerate excited states at ambient temperatures.« less
Authors:
 [1] ;  [1]
  1. Univ. at Buffalo, NY (United States). Dept. of Chemistry; State Univ. of New York (SUNY), Buffalo, NY (United States)
Publication Date:
Grant/Contract Number:
SC0001136; FG02-09ER16066
Type:
Published Article
Journal Name:
Journal of Chemical Theory and Computation
Additional Journal Information:
Journal Volume: 12; Journal Issue: 11; Journal ID: ISSN 1549-9618
Publisher:
American Chemical Society
Research Org:
Univ. at Buffalo, State Univ of New York, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1410732
Alternate Identifier(s):
OSTI ID: 1473849

Gendron, Frédéric, and Autschbach, Jochen. Ligand NMR Chemical Shift Calculations for Paramagnetic Metal Complexes: 5f1 vs 5f2 Actinides. United States: N. p., Web. doi:10.1021/acs.jctc.6b00462.
Gendron, Frédéric, & Autschbach, Jochen. Ligand NMR Chemical Shift Calculations for Paramagnetic Metal Complexes: 5f1 vs 5f2 Actinides. United States. doi:10.1021/acs.jctc.6b00462.
Gendron, Frédéric, and Autschbach, Jochen. 2016. "Ligand NMR Chemical Shift Calculations for Paramagnetic Metal Complexes: 5f1 vs 5f2 Actinides". United States. doi:10.1021/acs.jctc.6b00462.
@article{osti_1410732,
title = {Ligand NMR Chemical Shift Calculations for Paramagnetic Metal Complexes: 5f1 vs 5f2 Actinides},
author = {Gendron, Frédéric and Autschbach, Jochen},
abstractNote = {Ligand paramagnetic NMR (pNMR) chemical shifts of the 5f1 complexes UO2(CO3)35- and NpO2(CO3)34-, and of the 5f2 complexes PuO2(CO3)34- and (C5H5)3UCH3 are investigated by wave function theory calculations, using a recently developed sum-over-states approach within complete active space and restricted active space paradigm including spin–orbit (SO) coupling [J. Phys. Chem. Lett. 2015, 20, 2183-2188]. The experimental 13C pNMR shifts of the actinyl tris-carbonate complexes are well reproduced by the calculations. The results are rationalized by visualizing natural spin orbitals (NSOs) and spin-magnetizations generated from the SO wave functions, in comparison with scalar relativistic spin densities. The analysis reveals a complex balance between spin-polarization, spin and orbital magnetization delocalization, and spin-compensation effects due to SO coupling. This balance creates the magnetization due to the electron paramagnetism around the nucleus of interest, and therefore the pNMR effects. The calculated proton pNMR shifts of the (C5H5)3UCH3 complex are also in good agreement with experimental data. Because of the nonmagnetic ground state of (C5H5)3UCH3, the 1H pNMR shifts arise mainly from the magnetic coupling contributions between the ground state and low-energy excited states belonging to the 5f manifold, along with the thermal population of degenerate excited states at ambient temperatures.},
doi = {10.1021/acs.jctc.6b00462},
journal = {Journal of Chemical Theory and Computation},
number = 11,
volume = 12,
place = {United States},
year = {2016},
month = {10}
}