10.1021/ic301764t.s002
Christos Lampropoulos
Christos
Lampropoulos
Muralee Murugesu
Muralee
Murugesu
Andrew
G. Harter
Andrew
G.
Harter
Wolfgang Wernsdofer
Wolfgang
Wernsdofer
Stephen Hill
Stephen
Hill
Naresh S. Dalal
Naresh S.
Dalal
Arneil P. Reyes
Arneil P.
Reyes
Philip L. Kuhns
Philip L.
Kuhns
Khalil A. Abboud
Khalil A.
Abboud
George Christou
George
Christou
Synthesis, Structure,
and Spectroscopic and Magnetic Characterization of [Mn<sub>12</sub>O<sub>12</sub>(O<sub>2</sub>CCH<sub>2</sub>Bu<sup>t</sup>)<sub>16</sub>(MeOH)<sub>4</sub>]·MeOH, a Mn<sub>12</sub> Single-Molecule
Magnet with True Axial Symmetry
American Chemical Society
2013
satellite peaks
hysteresis loops
quadrupole splitting
field orientation
True Axial SymmetryThe synthesis
10 ground state
quantum tunneling
resonance spectra
400 mK
AC
SMM
360 GHz
field values
quantum tunneling regime
Mn 12 environments
Mn 12 family
NMR
DC
Mn 12O
carboxylate substitution
magnetization steps
Magnetic Characterization
2013-01-07 00:00:00
Dataset
https://acs.figshare.com/articles/dataset/Synthesis_Structure_and_Spectroscopic_and_Magnetic_Characterization_of_Mn_sub_12_sub_O_sub_12_sub_O_sub_2_sub_CCH_sub_2_sub_Bu_sup_t_sup_sub_16_sub_MeOH_sub_4_sub_MeOH_a_Mn_sub_12_sub_Single_Molecule_Magnet_with_True_Axial_Symmetry/2454988
The synthesis and properties are reported of a rare example
of a Mn<sub>12</sub> single-molecule magnet (SMM) in truly axial symmetry
(tetragonal, <i>I</i>4̅). [Mn<sub>12</sub>O<sub>12</sub>(O<sub>2</sub>CCH<sub>2</sub>Bu<sup>t</sup>)<sub>16</sub>(MeOH)<sub>4</sub>]·MeOH (<b>3</b>·MeOH) was synthesized by
carboxylate substitution on [Mn<sub>12</sub>O<sub>12</sub>(O<sub>2</sub>CMe)<sub>16</sub>(H<sub>2</sub>O)<sub>4</sub>]·2MeCO<sub>2</sub>H·4H<sub>2</sub>O (<b>1</b>). The complex was found to
possess an <i>S</i> = 10 ground state, as is typical for
the Mn<sub>12</sub> family, and displayed both frequency-dependent
out-of-phase AC susceptibility signals and hysteresis loops in single-crystal
magnetization vs DC field sweeps. The loops also exhibited quantum
tunneling of magnetization steps at periodic field values. Single-crystal,
high-frequency electron paramagnetic resonance spectra on <b>3·</b>MeOH using frequencies up to 360 GHz revealed perceptibly sharper
signals than for <b>1</b>. Moreover, careful studies as a function
of the magnetic field orientation did not reveal any satellite peaks,
as observed for <b>1</b>, suggesting that the crystals of <b>3</b> are homogeneous and do not contain multiple Mn<sub>12</sub> environments. In the single-crystal <sup>55</sup>Mn NMR spectrum
in zero applied field, three well-resolved peaks were observed, which
yielded hyperfine and quadrupole splitting at three distinct sites.
However, observation of a slight asymmetry in the Mn<sup>4+</sup> peak
was detectable, suggesting a possible decrease in the local symmetry
of the Mn<sup>4+</sup> site. Spin–lattice (<i>T</i><sub>1</sub>) relaxation studies were performed on single crystals
of <b>3</b>·MeOH down to 400 mK in an effort to approach
the quantum tunneling regime, and fitting of the data using multiple
functions was employed. The present work and other recent studies
continue to emphasize that the new generation of truly high-symmetry
Mn<sub>12</sub> complexes are better models for thorough investigation
of the physical properties of SMMs than their predecessors such as <b>1</b>.