TY - JOUR
T1 - The effect of the electronic structure and flexibility of the counteranions on magnetization relaxation in [Dy(L)2(H2O)5]3+ (L = phosphine oxide derivative) pentagonal bipyramidal SIMs
AU - Diáz-Ortega, Ismael F.
AU - Herrera, Juan Manuel
AU - Dey, Sourav
AU - Nojiri, Hiroyuki
AU - Rajaraman, Gopalan
AU - Colacio, Enrique
N1 - Funding Information:
Financial support from Ministerio de Economía y Competitividad (MINECO) for Projects CTQ2014-56312-P and PGC2018-102052-B-C21, the Junta de Andalucía (FQM-195), FEDER project A-FQM-172-UGR18 and the University of Granada is gratefully acknowledged. A part of this work was carried out at HFLSM, IMR, Tohoku University. I. F. D. O. also acknowledges support by COLABS. GR would like to thank the SERB (CRG/2018/000430) for financial support. S. D. thanks the UGC for a Senior Research Fellowship.
PY - 2020/2/7
Y1 - 2020/2/7
N2 - We report here a new DyIII-SIM [Dy(OPCy3)2(H2O)5](CF3SO3)3·2OPCy3 (OPCy3 = tricyclohexylphosphine oxide) with a pentagonal bipyramidal geometry, which exhibits a blocking temperature TB = 8.5 K and an anisotropy barrier Ueff = 562 K. Ab initio calculations show that this complex exhibits the largest Ucalc = 732 K among the DyIII-SIM complexes containing the [Dy(L)2(H2O)5]3+ (L = phosphine oxide derivative) cationic unit, which is essentially due to the electronic effects of the triflate anion that increase the charge difference between the oxygen atoms of the ligands L coordinated in axial positions and those belonging to the equatorial water molecules. This charge difference enhancement, which is also reflected in a larger difference between the corresponding Dy-O distances (Δ), appears to be the driving force to increase the Ucalc value. The comparatively smaller experimental Ueff value observed for this compound has been justified by the flexibility of the structural network due to the size of the triflate counteranions. The absence of a clear correlation between TB and Ueff (or Ucalc) suggests the involvement of Raman and QTM mechanisms in the magnetization relaxation process.
AB - We report here a new DyIII-SIM [Dy(OPCy3)2(H2O)5](CF3SO3)3·2OPCy3 (OPCy3 = tricyclohexylphosphine oxide) with a pentagonal bipyramidal geometry, which exhibits a blocking temperature TB = 8.5 K and an anisotropy barrier Ueff = 562 K. Ab initio calculations show that this complex exhibits the largest Ucalc = 732 K among the DyIII-SIM complexes containing the [Dy(L)2(H2O)5]3+ (L = phosphine oxide derivative) cationic unit, which is essentially due to the electronic effects of the triflate anion that increase the charge difference between the oxygen atoms of the ligands L coordinated in axial positions and those belonging to the equatorial water molecules. This charge difference enhancement, which is also reflected in a larger difference between the corresponding Dy-O distances (Δ), appears to be the driving force to increase the Ucalc value. The comparatively smaller experimental Ueff value observed for this compound has been justified by the flexibility of the structural network due to the size of the triflate counteranions. The absence of a clear correlation between TB and Ueff (or Ucalc) suggests the involvement of Raman and QTM mechanisms in the magnetization relaxation process.
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U2 - 10.1039/c9qi01412h
DO - 10.1039/c9qi01412h
M3 - Article
AN - SCOPUS:85079353961
VL - 7
SP - 689
EP - 699
JO - Inorganic Chemistry Frontiers
JF - Inorganic Chemistry Frontiers
SN - 2052-1545
IS - 3
ER -