Intramolecular Ferromagnetism in Di‐Nuclear 3d‐Transition‐Metal Single‐Molecule Magnets by Pseudo‐Serial Arrangement

Di‐nuclear citrate complexes, [CH6N3]2[M2(citH)2(H2O)4] ⋅ 2H2O (citH4=citric acid; M=FeII (Fe‐2), CoII (Co‐2), and NiII (Ni‐2)), are synthesized. The ligand, citH3−, is deprotonated only at the three carboxy groups, which is different from the previously reported tetra‐nuclear structures with cit4−...

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Bibliographic Details
Published in:Chemistry : a European journal 2023-03, Vol.29 (13)
Main Authors: Wakizaka, Masanori, Sato, Tetsu, Yoshino, Yuko, Takaishi, Shinya, Yamashita, Masahiro
Format: Article
Language:English
Subjects:
Anisotropy
Chemistry
Citric acid
Cobalt
Density functional theory
Dipole interactions
Ferromagnetism
Iron
Ligands
Magnetic dipoles
Magnetic induction
Magnetic measurement
Magnetic relaxation
Magnets
Metal ions
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Summary:Di‐nuclear citrate complexes, [CH6N3]2[M2(citH)2(H2O)4] ⋅ 2H2O (citH4=citric acid; M=FeII (Fe‐2), CoII (Co‐2), and NiII (Ni‐2)), are synthesized. The ligand, citH3−, is deprotonated only at the three carboxy groups, which is different from the previously reported tetra‐nuclear structures with cit4− ligands. Magnetic measurements reveal that these complexes have intramolecular ferromagnetism with J=∼0 cm−1 (Ni‐2), 0.02 cm−1 (Co‐2), and 0.04 cm−1 (Fe‐2). Co‐2 and Fe‐2 show slow magnetic relaxation, and are field‐induced SMMs with activation energy of spin‐reversal Ueff=27 cm−1 (Co‐2) and 4.2 cm−1 (Fe‐2). Density functional theory calculations indicate that the uniaxial anisotropy along the z‐axis of each metal ion center forms the pseudo‐serial arrangement, leading to intramolecular ferromagnetism via the magnetic dipole interaction. This work demonstrates the creation of ferromagnetic SMMs by the magnetic dipole engineering of 3d di‐nuclear metal ion centers.
ISSN:0947-6539
1521-3765
DOI:10.1002/chem.202203421