Boris Le Guennic (ISCR, Rennes)

Lanthanide-based single molecule magnets: contributions and actual limits of ab initio calculations

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Complexes containing trivalent lanthanide ions are of great interest in molecular magnetism. They can give rise to SMM with slow magnetic relaxation, uniaxial magnetic anisotropy and high-energy barrier to the reversal of the magnetic moment. These features originate from the subtle interplay between the spin-orbit coupling and the crystal field interaction created by the ligands surrounding the lanthanide ion. Few general rules for building SMM have been formulated but no fundamental magneto-structural relationship explaining the behavior of lanthanide-based SMM has been proposed yet [1].

To this end, and in addition to experimental evidences (SQUID magnetometry, EPR spectroscopy, polarized neutron diffraction…) ab initio calculations (SA-CASSCF/PT2/SISO) are one of the most appropriate theoretical tools to get reliable insights into the electronic structure of these compounds. Herein, the recent elucidation of the magnetic behavior of several lanthanide-based complexes is reported [2]. The limits of this computational approach is discussed.

[1] a) J.D. Rinehart, J. R. Long Chem. Sci. 2011, 2, 2078. b) L. Ungur, L. Chibotaru Phys. Chem. Chem. Phys.,  2011, 13, 20086. c) J. J. Baldovi, S. Cardona-Serra, J. M. Clemente-Juan, E. Coronado, A. Gaita-Arino; A. Palii, Inorg. Chem. 2012, 51, 12565.

[2] a) T. T. da Cunha, J. Jung, M.-E. Boulon, G. Campo, F. Pointillart, C. L. M. Pereira, B. Le Guennic, O. Cador, K. Bernot, F. Pineider, S. Golhen, L. Ouahab J. Am. Chem. Soc. 2013, 135, 16332. b) F. Pointillart, B. Le Guennic, O. Cador, O. Maury, L. Ouahab, Acc. Chem. Res., 2015, 48, 2834. c) J.-K. Ou-Yang, N. Saleh, G. Fernandez Garcia, L. Norel, F. Pointillart, T. Guizouarn, O. Cador, F. Totti, L. Ouahab, J. Crassous, B. Le Guennic Chem. Commun. 2016, 52, 14474. d) F. Pointillart, O. Cador, B. Le Guennic, L. Ouahab Coord. Chem., Rev. 2017, 346, 150. e) M. Xémard, A. Jaoul, M. Cordier, F. Molton, O. Cador, B. Le Guennic, C. Duboc, O. Maury, C. Clavaguéra, G. Nocton Angew. Chem. Int. Ed. 2017, 56, 4266. f) L. Norel, L. E. Darago, B. Le Guennic, K. Chakarawet, M. I. Gonzalez, J. H. Olshansky, S. Rigaut, J. R. Long Angew. Chem. Int. Ed. 2018, 57, 1933.