R. Sessoli, H. L. Tsai, A. R. Schake, S. Wang, J. B. Vincent et al., High-spin molecules: [Mn12O12(O2CR)16(H2O)4], Journal of the American Chemical Society, vol.115, issue.5, pp.1804-1816, 1993.
DOI : 10.1021/ja00058a027

D. Gatteschi, R. Sessoli, and J. Villain, Molecular Nanomagnets, 2006.
DOI : 10.1093/acprof:oso/9780198567530.001.0001
URL : https://hal.archives-ouvertes.fr/hal-00012648

C. J. Milios, A. Vinslava, W. Wernsdorfer, S. Moggach, S. Parsons et al., A Record Anisotropy Barrier for a Single-Molecule Magnet, Journal of the American Chemical Society, vol.129, issue.10, pp.2754-2755, 2007.
DOI : 10.1021/ja068961m

D. Yoshihara, S. Karasawa, and N. Koga, Cyclic Single-Molecule Magnet in Heterospin System, Journal of the American Chemical Society, vol.130, issue.32, pp.10460-10461, 2008.
DOI : 10.1021/ja802895d

P. C. Stamp and A. Gaita-arino, Spin-based quantum computers made by chemistry: hows and whys, J. Mater. Chem., vol.12, issue.12, pp.1718-1730, 2009.
DOI : 10.1021/ja801659m

L. F. Chibotaru and L. Ungur, calculation of anisotropic magnetic properties of complexes. I. Unique definition of pseudospin Hamiltonians and their derivation, The Journal of Chemical Physics, vol.137, issue.6, p.64112, 2012.
DOI : 10.1063/1.4739763

J. Cirera, E. Ruiz, S. Alvarez, and F. Neese, How to Build Molecules with Large Magnetic Anisotropy, Chemistry - A European Journal, vol.114, issue.16, pp.4078-4087, 2009.
DOI : 10.1002/chem.200801608

R. Maurice, C. De-graaf, and N. Guihéry, and ligand field analysis for the nonintuitive zero-field splitting in Mn(III) complexes, The Journal of Chemical Physics, vol.133, issue.8, p.84307, 2010.
DOI : 10.1063/1.3480014
URL : https://hal.archives-ouvertes.fr/hal-00863114

M. Atanasov, D. Ganyushin, D. A. Pantazis, K. Sivalingam, and F. Neese, Detailed Ab Initio First-Principles Study of the Magnetic Anisotropy in a Family of Trigonal Pyramidal Iron(II) Pyrrolide Complexes, Inorganic Chemistry, vol.50, issue.16, pp.7460-7477, 2011.
DOI : 10.1021/ic200196k

S. Gomez-coca, E. Cremades, N. Aliaga-alcalde, and E. Ruiz, Mononuclear Single-Molecule Magnets: Tailoring the Magnetic Anisotropy of First-Row Transition-Metal Complexes, Journal of the American Chemical Society, vol.135, issue.18, pp.7010-7018, 2013.
DOI : 10.1021/ja4015138

R. Maurice, N. Guihéry, R. Bastardis, and C. De-graaf, Rigorous Extraction of the Anisotropic Multispin Hamiltonian in Bimetallic Complexes from the Exact Electronic Hamiltonian, Journal of Chemical Theory and Computation, vol.6, issue.1, pp.55-65, 2010.
DOI : 10.1021/ct900473u
URL : https://hal.archives-ouvertes.fr/hal-00863055

R. Maurice, C. De-graaf, and N. Guihéry, (20) Kahn, O. Molecular Magnetism (21) Bo?a, R. Theoretical foundations of molecular magnetism, Phys. Rev. B Bo?a, R. Coord. Chem. Rev, vol.81, issue.248, pp.214427-757, 1993.

C. J. Calzado, J. Cabrero, J. Malrieu, and R. Caballol, Analysis of the magnetic coupling in binuclear complexes. I. Physics of the coupling, The Journal of Chemical Physics, vol.116, issue.7, pp.2728-2747, 2002.
DOI : 10.1063/1.1430740

C. J. Calzado, J. Cabrero, J. Malrieu, and R. Caballol, CI and DFT calculations, The Journal of Chemical Physics, vol.116, issue.10, pp.3985-4000, 2002.
DOI : 10.1063/1.1446024

R. Bastardis, N. Guihéry, and C. De-graaf, Isotropic non-Heisenberg terms in the magnetic coupling of transition metal complexes, The Journal of Chemical Physics, vol.129, issue.10, p.104102, 2008.
DOI : 10.1063/1.2975336
URL : https://hal.archives-ouvertes.fr/hal-00951624

J. Malrieu, R. Caballol, C. J. Calzado, C. De-graaf, and N. Guihéry, Magnetic Interactions in Molecules and Highly Correlated Materials: Physical Content, Analytical Derivation, and Rigorous Extraction of Magnetic Hamiltonians, Chemical Reviews, vol.114, issue.1, pp.429-492, 2014.
DOI : 10.1021/cr300500z
URL : https://hal.archives-ouvertes.fr/hal-00907025

R. Maurice, R. Bastardis, C. De-graaf, N. Suaud, T. Mallah et al., Universal Theoretical Approach to Extract Anisotropic Spin Hamiltonians, Journal of Chemical Theory and Computation, vol.5, issue.11, pp.2977-2984, 2009.
DOI : 10.1021/ct900326e
URL : https://hal.archives-ouvertes.fr/hal-00862784

R. Maurice, A. M. Pradipto, N. Guihéry, R. Broer, and C. De-graaf, Antisymmetric Magnetic Interactions in Oxo-Bridged Copper(II) Bimetallic Systems, Journal of Chemical Theory and Computation, vol.6, issue.10, pp.3092-3101, 2010.
DOI : 10.1021/ct100329n
URL : https://hal.archives-ouvertes.fr/hal-00864006

C. Bloch, Sur la th??orie des perturbations des ??tats li??s, Nuclear Physics, vol.6, issue.32, pp.329-347, 1958.
DOI : 10.1016/0029-5582(58)90116-0

P. Malmqvist, B. O. Roos, and B. Schimmelpfennig, The restricted active space (RAS) state interaction approach with spin???orbit coupling, Chemical Physics Letters, vol.357, issue.3-4, pp.230-240, 2002.
DOI : 10.1016/S0009-2614(02)00498-0

B. O. Roos and P. Malmqvist, Relativistic quantum chemistry: the multiconfigurational approach, Physical Chemistry Chemical Physics, vol.6, issue.11, pp.2919-2927, 2004.
DOI : 10.1039/b401472n

G. Karlström, R. Lindh, P. Malmqvist, B. O. Roos, U. Ryde et al., MOLCAS: a program package for computational chemistry, Computational Materials Science, vol.28, issue.2, pp.222-239, 2003.
DOI : 10.1016/S0927-0256(03)00109-5

B. O. Roos, R. Lindh, P. Malmqvist, V. Veryazov, and P. Widmark, Main Group Atoms and Dimers Studied with a New Relativistic ANO Basis Set, The Journal of Physical Chemistry A, vol.108, issue.15, pp.2851-2858, 2004.
DOI : 10.1021/jp031064+

B. O. Roos, R. Lindh, P. Malmqvist, V. Veryazov, and P. Widmark, New Relativistic ANO Basis Sets for Transition Metal Atoms, The Journal of Physical Chemistry A, vol.109, issue.29, pp.6575-6579, 2005.
DOI : 10.1021/jp0581126

D. Gatteschi and R. Sessoli, Quantum Tunneling of Magnetization and Related Phenomena in Molecular Materials, Angewandte Chemie International Edition, vol.42, issue.3, pp.268-297, 2003.
DOI : 10.1002/anie.200390099

A. L. Barra, D. Gatteschi, and R. Sessoli, High-frequency EPR spectra of a molecular nanomagnet: Understanding quantum tunneling of the magnetization, Physical Review B, vol.56, issue.13, pp.8192-8198, 1997.
DOI : 10.1103/PhysRevB.56.8192

S. Hill, J. A. Perenboom, N. S. Dalal, T. Hathaway, T. Stalcup et al., -Acetate, Physical Review Letters, vol.80, issue.11, pp.2453-2456, 1998.
DOI : 10.1103/PhysRevLett.80.2453
URL : https://hal.archives-ouvertes.fr/hal-00857728

A. Wilson, J. Lawrence, E. Yang, M. Nakano, D. N. Hendrickson et al., Magnetization tunneling in high-symmetry single-molecule magnets: Limitations of the giant spin approximation, Physical Review B, vol.74, issue.14, p.140403, 2006.
DOI : 10.1103/PhysRevB.74.140403

A. Abragam and B. Bleaney, Electron paramagnetic resonance of transition ions, 1986.

A. D. Buckingham, P. Pyykko, J. B. Robert, and L. Wiesenfeld, Symmetry rules for the indirect nuclear spin-spin coupling tensor revisited, Molecular Physics, vol.40, issue.1, pp.177-182, 1982.
DOI : 10.1080/00268978200101171

N. Gogoi, M. Thlijeni, C. Duhayon, and J. Sutter, ] Complex, Inorganic Chemistry, vol.52, issue.5, pp.2283-2285, 2013.
DOI : 10.1021/ic3027368