Temperature and pressure effects on the spin state of ferric ions in the [Fe(sal2-trien)][Ni(dmit)2] spin crossover complex
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 st...
| Main Authors: | , , , , , , |
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| Format: | Journal Article |
| Published: |
Pergamon
2008
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| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022369708003363# http://hdl.handle.net/20.500.11937/12334 |
| Summary: | 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, ?HHL=7 kJ/mol, entropy, ?SHL=29 J/Kmol, and the unit cell volume, ?VHL=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. |
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