EXPERIMENTAL RESULTS ON COUPLED ANALYSIS OF SPIN AND CHARGES DENSITIES OF Y AND GD COMPLES
N. Claiser,a B. Gillon,b M. Souhassou,a C. Lecomte,a N. K. Hansen,a Y. Pontillon,c A. Caneschi,d D. Gatteschi,d C. Carbonera,d A. Bencini,d A. Coussonb and E.
Lelivre-Bernae
aL.C.M.3B., UMR CNRS 7036, FacultŽ des
Sciences, BP 239, 54506 Vandoeuvre-ls-Nancy, France; bLaboratoire LŽon Brillouin, CEA-CNRS,
Centre dÕEtude de Saclay, 91191 Gif/Yvette, France; cDRN/DEC, Centre dÕEtudes NuclŽaires de
Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France; dDepartment of Chemistry, University of
Florence, Via Maragliano 77, 50144 Firenze, Italy; eInstitut Laue-Langevin, 6 rue Jules
Horowitz, BP 156, 38042 Grenoble Cedex 9, France (claiser@lcm3b.uhp-nancy.fr)
Within the vast field of
molecular magnetism, we have studied two complexes in which the semiquinoato
radical (DTBSQ=3,5-di-tertbutyl- semiquinonate, S=1/2) coordinates a heavy atom
(Yttrium, S=0 or Gadolinium, S=7/2). Two HBPz3
(hydrotrispyrazolylborate) complete the coordination sphere [1]. On the basis
of the experimental electron and spin densities, our aim was to highlight the
interactions at the microscopic level that play an important role in the
magnetic behaviour observed in these two complexes.
The total electron density,
obtained by a high resolution X-ray diffraction experiment, and the spin
density, obtained by a polarised neutron diffraction experiment, were
determined on the two complexes: Y-SQ and Gd-SQ. The topological analysis of
the total electron density [2, 3] was used to characterise
quantitatively the interatomic interactions, particularly between the ligands
and the central ion. This method gives also access to the net atomic charges,
useful for the comprehension of the charge transfer inside the complexes. In
this study, we will present the experimental
spin density distribution and the topological properties of the electron
density in the two complexes and confront them to the DFT calculations results.