Can novel dinuclear Ni–Gd complexes give supplementary information on the Ni–Gd magnetic interaction?
Résumé
Two new heterodinuclear Ni–Gd complexes with Ni–(O2)–Gd cores, a practically planar one and a highly distorted one, are reported and structurally characterized. DFT calculations allow calculation of the JNiGd interaction parameters, in good agreement with the experimental data. It has been previously shown in such dinuclear complexes with double-phenoxo bridges that the hinge angle, defined as the angle between the O Ni O and O Gd O planes and the Ni–O–Gd angles, involving the bridging oxygen atoms and the metal ions, play a major role in the value of the resulting magnetic interaction. We demonstrate with help of DFT calculations that these parameters are not sufficient to understand the magnetic interaction change observed in the distorted Ni–(O2)–Gd core. This work allows to explain why tripodal ligands yielding face-sharing 3d–Gd complexes with three phenoxo bridges give JNiGd values lower than in planar edge-sharing 3d–Gd complexes. Eventually these geometric changes do not favor the SMM properties of the corresponding Ni–Dy dinuclear complex.