Polarized Neutron Diffraction to Probe Local Magnetic Anisotropy of a Low-Spin Fe(III) Complex

Karl Ridier (1) , Abhishake Mondal (2) , Corentin Boilleau (3, 4) , Olivier Cador (4) , Béatrice Gillon (1) , Grégory Chaboussant (1) , Boris Le Guennic (4) , Karine Costuas (4) , Rodrigue Lescouëzec (2)

1 LLB - UMR 12 - Laboratoire Léon Brillouin
2 ERMMES - Equipe de Recherche en Matériaux Moléculaires et Spectroscopies
3 SNS - Scuola Normale Superiore di Pisa
4 ISCR - Institut des Sciences Chimiques de Rennes

We have determined by polarized neutron diffraction (PND) the low-temperature molecular magnetic susceptibility tensor of the anisotropic low-spin complex PPh4 [Fe(III) (Tp)(CN)3 ]⋅H2 O. We found the existence of a pronounced molecular easy magnetization axis, almost parallel to the C3 pseudo-axis of the molecule, which also corresponds to a trigonal elongation direction of the octahedral coordination sphere of the Fe(III) ion. The PND results are coherent with electron paramagnetic resonance (EPR) spectroscopy, magnetometry, and ab initio investigations. Through this particular example, we demonstrate the capabilities of PND to provide a unique, direct, and straightforward picture of the magnetic anisotropy and susceptibility tensors, offering a clear-cut way to establish magneto-structural correlations in paramagnetic molecular complexes

Keywords: polarized neutron diffraction; EPR spectroscopy; density functional calculations; molecular magnetism; magnetic anisotropy

Domains: Chemical Sciences; Coordination chemistry

Karl Ridier, Abhishake Mondal, Corentin Boilleau, Olivier Cador, Béatrice Gillon, et al.. Polarized Neutron Diffraction to Probe Local Magnetic Anisotropy of a Low-Spin Fe(III) Complex. Angewandte Chemie International Edition, 2016, 55 (12), pp.3963-3967. ⟨10.1002/anie.201511354⟩. ⟨hal-01279121⟩