Temperature and pressure effects on the spin state of ferric ions in the [Fe(sal2-trien)][Ni(dmit)2] spin crossover complex
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- 作者：Petra Á ; . Szilá ; gyi ; Sté ; phane Dorbes ; Gá ; bor Molná ; r ; José ; Antonio Real ; Zoltá ; n Homonnay ; Christophe Faulmann ; Azzedine Bousseksou
- 关键词：A. Inorganic compounds ; C. High pressure ; D. Magnetic properties ; D. Phase transitions
- 刊名：Journal of Physics and Chemistry of Solids
- 出版年：2008
- 出版时间：November 2008
- 年：2008
- 卷：69
- 期：11
- 页码：2681-2686
- 全文大小：479 K
文摘
Thermal and pressure effects have been investigated on the [Fe(sal2-trien)][Ni(dmit)2] spin crossover complex by means of Mössbauer spectroscopic, calorimetric, X-ray diffraction and magnetic susceptibility measurements. The complex displays a complete thermal spin transition between the and spin states of FeIII near 245 K with a hysteresis loop of ca. 30 K. This transition is characterised by a change of the enthalpy, ΔHHL=7 kJ/mol, entropy, ΔSHL=29 J/Kmol, and the unit cell volume, ΔVHL=15.4 Å3. Under hydrostatic pressures up to 5.7 kbar the thermal transition shifts to higher temperatures by ca. 16 K/kbar. Interestingly, at a low applied pressure of 500 bar the hysteresis loop becomes wider (ca. 61 K) and the transition is blocked at 50 % upon cooling, indicating a possible (irreversible) structural phase transition under pressure.