TY - JOUR
T1 - Heterospin single-molecule magnets with extra-large anisotropic barrier
AU - Yoshihara, Daisuke
AU - Karasawa, Satoru
AU - Koga, Noboru
N1 - Funding Information:
This work was partially supported by “Nanotechnology Support Project” of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. D.Y. acknowledges a scholarship by the Japan Society for the Promotion of Science (JSPS).
PY - 2011/11/28
Y1 - 2011/11/28
N2 - The mixtures of Co(X-hfpip)2; X = I and H, and bisdiazo-dipyridine ligands, D2py2(TBA), in 1:1 ratios gave the discrete cobalt complexes, 1 and 2, respectively. The molecular structures for 1 and 2 revealed by X-ray crystallography were cyclic 2:2 cobalt complexes formulated as [(Co(X-hfpip)2)2(D2py2(TBA)) 2], in which the cobalt units were compressed octahedra. After irradiation of the microcrystalline samples, the resulting Co-carbene complexes, 1c and 2c, showed SMM behaviors exhibiting slow magnetic relaxations. In dc and ac magnetic susceptibility experiments, the activation barrier, U eff, for reorientation of the magnetic moment were estimated to be 139 and 135 K for 1c and 2c, respectively, and the hysteresis loops of the magnetization (the coercive force, Hc, and 26 and 15 kOe at 1.9 K for 1c and 2c, respectively) were observed. In addition, the values of the quantum tunneling time, τQ, were determined to be 1.1 × 10 5 and 5.4 × 105 s (t1/2 = 21 and 104 h) for 1c and 2c, respectively, below 2.5 K.
AB - The mixtures of Co(X-hfpip)2; X = I and H, and bisdiazo-dipyridine ligands, D2py2(TBA), in 1:1 ratios gave the discrete cobalt complexes, 1 and 2, respectively. The molecular structures for 1 and 2 revealed by X-ray crystallography were cyclic 2:2 cobalt complexes formulated as [(Co(X-hfpip)2)2(D2py2(TBA)) 2], in which the cobalt units were compressed octahedra. After irradiation of the microcrystalline samples, the resulting Co-carbene complexes, 1c and 2c, showed SMM behaviors exhibiting slow magnetic relaxations. In dc and ac magnetic susceptibility experiments, the activation barrier, U eff, for reorientation of the magnetic moment were estimated to be 139 and 135 K for 1c and 2c, respectively, and the hysteresis loops of the magnetization (the coercive force, Hc, and 26 and 15 kOe at 1.9 K for 1c and 2c, respectively) were observed. In addition, the values of the quantum tunneling time, τQ, were determined to be 1.1 × 10 5 and 5.4 × 105 s (t1/2 = 21 and 104 h) for 1c and 2c, respectively, below 2.5 K.
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U2 - 10.1016/j.poly.2011.04.013
DO - 10.1016/j.poly.2011.04.013
M3 - Article
AN - SCOPUS:82255186482
SN - 0277-5387
VL - 30
SP - 3211
EP - 3217
JO - Polyhedron
JF - Polyhedron
IS - 18
ER -