Spin‐State Ordering on One Sub‐lattice of a Mononuclear Iron(III) Spin Crossover Complex Exhibiting LIESST and TIESST |
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| Authors: | Dr Kevin D Murnaghan Dr Chiara Carbonera Dr Loic Toupet Dr Michael Griffin Dr Marinela M Dîrtu Dr Cédric Desplanches Prof?Dr Yann Garcia Prof Eric Collet Prof Jean‐François Létard Dr Grace G Morgan |
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| Institution: | 1. School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4 (Ireland);2. CNRS, ICMCB, Université de Bordeaux, Bordeaux (France);3. Present address: Solar Energy Department, Research Centre for non‐conventional Energies, Istituto ENI Donegani, ENI S.pa. Via G. Fauser 4, 28100 Novara (Italy);4. Institut de Physique de Rennes, Université de Rennes 1, UMR UR1‐CNRS 6251, 35000 Rennes (France);5. Institute of Condensed Matter and Nanosciences, Molecules, Solids and Reactivity (IMCN/MOST), Université Catholique de Louvain, Place L. Pasteur 1, 1348 Louvain‐la‐neuve (Belgium) |
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| Abstract: | The two‐step spin crossover in mononuclear iron(III) complex Fe(salpm)2]ClO4 ? 0.5 EtOH ( 1 ) is shown to be accompanied by a structural phase transition as concluded from 57Fe Mössbauer spectroscopy and single crystal X‐ray diffraction, with spin‐state ordering on just one of two sub‐lattices in the intermediate magnetic and structural phase. The complex also exhibits thermal‐ and light‐induced spin‐state trapping (TIESST and LIESST), and relaxation from the LIESST and TIESST excited states occurs via the broken symmetry intermediate phase. Two relaxation events are evident in both experiments, that is, two T(LIESST) and two T(TIESST) values are recorded. The change in symmetry which accompanies the TIESST effect was followed in real time using single crystal diffraction. After flash freezing at 15 K the crystal was warmed to 40 K at which temperature superstructure reflections were observed to appear and disappear within a 10 000 s time range. In the frame of the international year of crystallography, these results illustrate how X‐ray diffraction makes it possible to understand complex ordering phenomena. |
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| Keywords: | broken symmetry iron LIESST magnetic properties TIESST |
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