On the dielectric properties of the spin crossover complex [Fe(bpp)2] [BF4]2

Thomas Guillon (1) , Sébastien Bonhommeau (1, 2) , José Sánchez Costa (3) , Antoine Zwick (2) , Jean-François Létard (3) , Philippe Demont (4) , Gábor Molnár (1) , Azzedine Bousseksou (1)

1 LCC - Laboratoire de chimie de coordination
2 Laboratoire Physique des Solides de Toulouse
3 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
4 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux

The thermal variation of the dielectric constant in the spin crossover complex [Fe(bpp)2] [BF4]2 displays a 16 K large hysteresis loop centered around 178 K corresponding to the spin transition temperatures. Unexpectedly, the dielectric constant has a higher value in the low-spin state. DFT calculations were carried out to determine the microscopic electronic polarizabilities, but these latter could not be correlated with the macroscopic permittivity changes pointing the importance of the effect of the counter-anions which must be necessarily taken into account in future DFT calculations.

Mots clés: Dielectric properties of solids and liquids; Infrared and Raman spectra; Density functional theory; Spin crossover

Domaines: Matériaux

Thomas Guillon, Sébastien Bonhommeau, José Sánchez Costa, Antoine Zwick, Jean-François Létard, et al.. On the dielectric properties of the spin crossover complex [Fe(bpp)2] [BF4]2. physica status solidi (a), 2006, 203 (11), pp.2974-2980. ⟨10.1002/pssa.200567103⟩. ⟨hal-00104157⟩