Scientific article

The [Fe(etz)6](BF4)2 Spin-Crossover System - Part Two: Hysteresis in the LIESST Regime

Published inChemistry, vol. 2, no. 11, p. 1435-1439
Publication date1996

In the [Fe(etz)6](BF4)2 spincrossover system the iron(II) complexes occupy two nonequivalent lattice sites, sites A and B. Complexes on site A show a thermal high-spin (HS) low-spin (LS) transition at 105 K, whereas complexes on site B remain in the HS state down to 10 K. Complexes on both sites exhibit light-induced spin state conversions (LIESST) at 20 K: LS HS on site A with = 514.5 nm, and HS LS on site B with = 820 nm. The relaxation processes subsequent to the HS LS conversion on site B reveal a light-induced HSLS bistability for the complexes on site B at 70 K. The bistability as well as the absence of a thermal spin transition on site B are attributed to a thermal hysteresis for the B-site complexes with a critical temperature Tc77 K on heating. This hysteresis can be interpreted in terms of strong cooperative effects of elastic origin, which, in addition, cause characteristic deviations of the relaxation on site B from first-order kinetics (self-acceleration). In contrast, the HS LS relaxation at 60 K on site A after irradiation with = 514.5 nm shows an unusual self-retardation.

  • Hysteresis
  • Iron complexes
  • Spin crossover
  • Tetrazoles
Research group
Citation (ISO format)
HINEK, Roland et al. The [Fe(etz)6](BF4)2 Spin-Crossover System - Part Two: Hysteresis in the LIESST Regime. In: Chemistry, 1996, vol. 2, n° 11, p. 1435–1439. doi: 10.1002/chem.19960021116
ISSN of the journal0947-6539

Technical informations

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