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A Bis‐Binuclear Ni II Complex with Easy and Hard Axes of Magnetization: Complementary Experimental and Theoretical Insights
Author(s) -
ElKhatib Fatima,
Cahier Benjamin,
LópezJordà Maurici,
Guillot Régis,
Rivière Eric,
Hafez Hala,
Saad Zeinab,
Guihéry Nathalie,
Mallah Talal
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201700977
Subject(s) - magnetization , nickel , crystallography , square pyramid , octahedron , octahedral molecular geometry , ligand (biochemistry) , geometry , coordination geometry , bond length , chemistry , metal , square pyramidal molecular geometry , molecular geometry , materials science , condensed matter physics , crystal structure , physics , molecule , magnetic field , biochemistry , receptor , mathematics , hydrogen bond , organic chemistry , quantum mechanics
The preparation of a tetranuclear Ni II complex, constructed of two binuclear species each containing a macrocyclic cryptand‐like ligand and bridged by a nitrate anion, is reported. The metal ions within the binuclear species are hexacoordinate with different distorted environments. One nickel site, Ni1, has as a compressed octahedral geometry, whereas the other nickel site, Ni2, has a geometry closer to a square pyramid due to the presence of a long metal–ligand bond length. A study of the magnetic properties showed that the intradimer exchange coupling is larger than the interdimer coupling due to differences in the metal–ligand intra‐ and interdimer bond lengths, as confirmed by broken‐symmetry DFT calculations. Wave‐function‐based calculations allowed analysis of both the nature and the magnitude of the magnetic anisotropy of the two Ni sites. The Ni1 and Ni2 sites have, respectively, easy and hard axes of magnetization that are almost orthogonal. Magnetostructural correlations showed that the hard axis of magnetization of Ni2 is due to its geometry, which is closer to square‐pyramidal despite the hexacoordination. On the other hand, the easy axis of magnetization of the Ni1 site is a result of the compressed octahedral geometry.