Details
| Originalsprache | Englisch |
|---|---|
| Seiten (von - bis) | 3025-3033 |
| Seitenumfang | 9 |
| Fachzeitschrift | Inorganic chemistry |
| Jahrgang | 40 |
| Ausgabenummer | 13 |
| Publikationsstatus | Veröffentlicht - 18 Juni 2001 |
| Extern publiziert | Ja |
Abstract
The spin crossover system, [Fe(bzimpy)2](ClO4)2 ·0.25H2O, was reinvestigated above room temperature (bzimpy = 2,6-bis(benzimidazol-2-yl)pyridine). The system exhibits an abrupt low-spin to high-spin transition at Tc = 403 K. Liberation of a fractional amount of water does not affect the spin crossover: the system is perfectly reversible with a hysteresis width of ΔT = 12 K. The existence of the hysteresis at such high temperature determines that the lowest limit of the solid-state cooperativity parameter is Jlk > 403 K despite long iron(II) separations (10 Å). The high cooperativeness has been assigned to a perfect π-stacking of the benzimidazole rings in the crystal lattice at a distance as short as 3.6 Å. Variable-temperature IR data and the heat capacity measurements match well the magnetic data. The thermodynamic properties are ΔH = 17 kJ mol-1, ΔS = 43 J K-1 mol-1, so that the entropy of the spin transition shows a considerable contribution from the molecular vibrations. A theoretical model has been applied in fitting the magnetic data along the whole hysteresis path. A statistical distribution of the cooperativity parameter led to the feature that angled walls of the hysteresis loop are well reproduced.
ASJC Scopus Sachgebiete
- Chemie (insg.)
- Physikalische und Theoretische Chemie
- Chemie (insg.)
- Anorganische Chemie
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in: Inorganic chemistry, Jahrgang 40, Nr. 13, 18.06.2001, S. 3025-3033.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Strong cooperativeness in the mononuclear iron(II) derivative exhibiting an abrupt spin transition above 400 K
AU - Boča, R.
AU - Boča, M.
AU - Dlháň, L.
AU - Falk, K.
AU - Fuess, H.
AU - Haase, W.
AU - Jaroščiak, R.
AU - Papánková, B.
AU - Renz, F.
AU - Vrbová, M.
AU - Werner, R.
PY - 2001/6/18
Y1 - 2001/6/18
N2 - The spin crossover system, [Fe(bzimpy)2](ClO4)2 ·0.25H2O, was reinvestigated above room temperature (bzimpy = 2,6-bis(benzimidazol-2-yl)pyridine). The system exhibits an abrupt low-spin to high-spin transition at Tc = 403 K. Liberation of a fractional amount of water does not affect the spin crossover: the system is perfectly reversible with a hysteresis width of ΔT = 12 K. The existence of the hysteresis at such high temperature determines that the lowest limit of the solid-state cooperativity parameter is Jlk > 403 K despite long iron(II) separations (10 Å). The high cooperativeness has been assigned to a perfect π-stacking of the benzimidazole rings in the crystal lattice at a distance as short as 3.6 Å. Variable-temperature IR data and the heat capacity measurements match well the magnetic data. The thermodynamic properties are ΔH = 17 kJ mol-1, ΔS = 43 J K-1 mol-1, so that the entropy of the spin transition shows a considerable contribution from the molecular vibrations. A theoretical model has been applied in fitting the magnetic data along the whole hysteresis path. A statistical distribution of the cooperativity parameter led to the feature that angled walls of the hysteresis loop are well reproduced.
AB - The spin crossover system, [Fe(bzimpy)2](ClO4)2 ·0.25H2O, was reinvestigated above room temperature (bzimpy = 2,6-bis(benzimidazol-2-yl)pyridine). The system exhibits an abrupt low-spin to high-spin transition at Tc = 403 K. Liberation of a fractional amount of water does not affect the spin crossover: the system is perfectly reversible with a hysteresis width of ΔT = 12 K. The existence of the hysteresis at such high temperature determines that the lowest limit of the solid-state cooperativity parameter is Jlk > 403 K despite long iron(II) separations (10 Å). The high cooperativeness has been assigned to a perfect π-stacking of the benzimidazole rings in the crystal lattice at a distance as short as 3.6 Å. Variable-temperature IR data and the heat capacity measurements match well the magnetic data. The thermodynamic properties are ΔH = 17 kJ mol-1, ΔS = 43 J K-1 mol-1, so that the entropy of the spin transition shows a considerable contribution from the molecular vibrations. A theoretical model has been applied in fitting the magnetic data along the whole hysteresis path. A statistical distribution of the cooperativity parameter led to the feature that angled walls of the hysteresis loop are well reproduced.
UR - http://www.scopus.com/inward/record.url?scp=0035907416&partnerID=8YFLogxK
U2 - 10.1021/ic000807s
DO - 10.1021/ic000807s
M3 - Article
C2 - 11399169
AN - SCOPUS:0035907416
VL - 40
SP - 3025
EP - 3033
JO - Inorganic chemistry
JF - Inorganic chemistry
SN - 0020-1669
IS - 13
ER -