10.1021/acs.inorgchem.6b01544.s004
Lei Chen
Lei
Chen
Hui-Hui Cui
Hui-Hui
Cui
Shelby E. Stavretis
Shelby E.
Stavretis
Seth C. Hunter
Seth C.
Hunter
Yi-Quan Zhang
Yi-Quan
Zhang
Xue-Tai Chen
Xue-Tai
Chen
Yi-Chen Sun
Yi-Chen
Sun
Zhenxing Wang
Zhenxing
Wang
You Song
You
Song
Andrey A. Podlesnyak
Andrey A.
Podlesnyak
Zhong-Wen Ouyang
Zhong-Wen
Ouyang
Zi-Ling Xue
Zi-Ling
Xue
Slow Magnetic Relaxations in Cobalt(II) Tetranitrate
Complexes. Studies of Magnetic Anisotropy by Inelastic Neutron Scattering
and High-Frequency and High-Field EPR Spectroscopy
American Chemical Society
2016
3 E 2
seven-coordinate geometries
tetranitrate cobalt anion
D value
X-ray diffraction studies
susceptibility measurements
anisotropy
HF-EPR data
INS studies
INS spectroscopy
inelastic neutron
magnetization relaxation
X-ray single-crystal diffraction
temperature-dependent alternating-current
600 Oe
cm
Inelastic Neutron Scattering
SMM
high-field EPR
dc field
calculation
HF-EPR spectroscopy
Co
CASPT
Ph 4
countercation
High-Field EPR Spectroscopy
D values
2 exhibit
distorted-dodecahedral configuration
Magnetic Anisotropy
Ph 4 P
field-induced single-molecule magnets
2016-12-06 22:03:27
Dataset
https://acs.figshare.com/articles/dataset/Slow_Magnetic_Relaxations_in_Cobalt_II_Tetranitrate_Complexes_Studies_of_Magnetic_Anisotropy_by_Inelastic_Neutron_Scattering_and_High-Frequency_and_High-Field_EPR_Spectroscopy/4290023
Three
mononuclear cobalt(II) tetranitrate complexes (A)<sub>2</sub>[Co(NO<sub>3</sub>)<sub>4</sub>] with different countercations, Ph<sub>4</sub>P<sup>+</sup> (<b>1</b>), MePh<sub>3</sub>P<sup>+</sup> (<b>2</b>), and Ph<sub>4</sub>As<sup>+</sup> (<b>3</b>), have
been synthesized and studied by X-ray single-crystal diffraction,
magnetic measurements, inelastic neutron scattering (INS), high-frequency
and high-field EPR (HF-EPR) spectroscopy, and theoretical calculations.
The X-ray diffraction studies reveal that the structure of the tetranitrate
cobalt anion varies with the countercation. <b>1</b> and <b>2</b> exhibit highly irregular seven-coordinate geometries, while
the central Co(II) ion of <b>3</b> is in a distorted-dodecahedral
configuration. The sole magnetic transition observed in the INS spectroscopy
of <b>1</b>–<b>3</b> corresponds to the zero-field
splitting (2(<i>D</i><sup>2</sup> + 3<i>E</i><sup>2</sup>)<sup>1/2</sup>) from 22.5(2) cm<sup>–1</sup> in <b>1</b> to 26.6(3) cm<sup>–1</sup> in <b>2</b> and
11.1(5) cm<sup>–1</sup> in <b>3</b>. The positive sign
of the <i>D</i> value, and hence the easy-plane magnetic
anisotropy, was demonstrated for <b>1</b> by INS studies under
magnetic fields and HF-EPR spectroscopy. The combined analyses of
INS and HF-EPR data yield the <i>D</i> values as +10.90(3),
+12.74(3), and +4.50(3) cm<sup>–1</sup> for <b>1</b>–<b>3</b>, respectively. Frequency- and temperature-dependent alternating-current
magnetic susceptibility measurements reveal the slow magnetization
relaxation in <b>1</b> and <b>2</b> at an applied dc field
of 600 Oe, which is a characteristic of field-induced single-molecule
magnets (SMMs). The electronic structures and the origin of magnetic
anisotropy of <b>1</b>–<b>3</b> were revealed by
calculations at the CASPT2/NEVPT2 level.