TY - JOUR
T1 - 11B Nuclear Spin-Electron Spin Interactions in 11B MAS NMR Spectra of Paramagnetic Metal Borohydrides
AU - Skibsted, Jørgen
AU - Payandeh, Seyedhosein
AU - Ley, Morten B.
AU - Jensen, Torben R.
N1 - Funding Information:
J.S. acknowledges the Carlsberg Foundation for an equipment grant (no. CF14-0138). The Innovation Fund Denmark (project HyFill-Fast) and the Danish Research Council for Nature and Universe (Danscatt) are also acknowledged. This research has received funding from the European Marie Curie Actions under ECOSTORE grant agreement no. 607040.
Publisher Copyright:
©
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/1
Y1 - 2021/1
N2 - Isotropic and anisotropic couplings between the 11B nuclear spin and the electron spin of paramagnetic electrons are observed in 11B MAS NMR spectra of α-Pr(BH4)3 and LiCe(BH4)3Cl. The 11B NMR spectra of the central and satellite transitions are strongly influenced by the anisotropic nuclear spin-paramagnetic electron spin dipole-dipole interaction, which affects the spectra in a similar manner as the 11B chemical shift anisotropy. The 11B MAS NMR spectra are analyzed numerically, considering the quadrupole interaction and the anisotropic paramagnetic electron-nuclear spin dipole coupling along with the relative orientation of the two tensorial interactions. The observed isotropic shifts (δobs) show a linear dependency with the inverse temperature for both compounds, indicating that δobs is dominated by the contribution from the isotropic hyperfine shift. A similar temperature dependency is observed for the paramagnetic shift anisotropy for α-Pr(BH4)3. The isotropic and anisotropic paramagnetic interactions are approximately 5 and 4 times larger for α-Pr(BH4)3 as compared to LiCe(BH4)3Cl. This reflects mainly the difference in electron spin for the Pr3+ and Ce3+ ions and that the B site in α-Pr(BH4)3 has two Pr3+ ions within a 3 Å distance, whereas boron in LiCe(BH4)3Cl only has a single Ce3+ site within this distance.
AB - Isotropic and anisotropic couplings between the 11B nuclear spin and the electron spin of paramagnetic electrons are observed in 11B MAS NMR spectra of α-Pr(BH4)3 and LiCe(BH4)3Cl. The 11B NMR spectra of the central and satellite transitions are strongly influenced by the anisotropic nuclear spin-paramagnetic electron spin dipole-dipole interaction, which affects the spectra in a similar manner as the 11B chemical shift anisotropy. The 11B MAS NMR spectra are analyzed numerically, considering the quadrupole interaction and the anisotropic paramagnetic electron-nuclear spin dipole coupling along with the relative orientation of the two tensorial interactions. The observed isotropic shifts (δobs) show a linear dependency with the inverse temperature for both compounds, indicating that δobs is dominated by the contribution from the isotropic hyperfine shift. A similar temperature dependency is observed for the paramagnetic shift anisotropy for α-Pr(BH4)3. The isotropic and anisotropic paramagnetic interactions are approximately 5 and 4 times larger for α-Pr(BH4)3 as compared to LiCe(BH4)3Cl. This reflects mainly the difference in electron spin for the Pr3+ and Ce3+ ions and that the B site in α-Pr(BH4)3 has two Pr3+ ions within a 3 Å distance, whereas boron in LiCe(BH4)3Cl only has a single Ce3+ site within this distance.
UR - http://www.scopus.com/inward/record.url?scp=85099049524&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.0c09829
DO - 10.1021/acs.jpcc.0c09829
M3 - Journal article
AN - SCOPUS:85099049524
SN - 1932-7447
VL - 125
SP - 1113
EP - 1124
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 1
ER -