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hal.structure.identifierInstitut Laue-Langevin [ILL]
hal.structure.identifierCristallographie, Résonance Magnétique et Modélisations [CRM2]
dc.contributor.authorLEGRAND, Vincent
hal.structure.identifierCristallographie, Résonance Magnétique et Modélisations [CRM2]
dc.contributor.authorPILLET, Sébastien
hal.structure.identifierInstitut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
dc.contributor.authorCARBONERA, Chiara
hal.structure.identifierCristallographie, Résonance Magnétique et Modélisations [CRM2]
dc.contributor.authorSOUHASSOU, Mohamed
hal.structure.identifierInstitut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
dc.contributor.authorLÉTARD, Jean-François
hal.structure.identifierInstitut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
dc.contributor.authorGUIONNEAU, Philippe
hal.structure.identifierCristallographie, Résonance Magnétique et Modélisations [CRM2]
dc.contributor.authorLECOMTE, Claude
dc.date.issued2007
dc.identifier.issn1434-1948
dc.description.abstractEn[Fe(btr)<sub>2</sub>(NCS)<sub>2</sub>]·H<sub>2</sub>O [btr=4,4′‐bis(1,2,4‐triazole)] is thearchetype of highly cooperative and low‐dimensional spin‐crossover complexes, which exhibit low‐spin (LS) to high‐spin (HS) light‐induced conversion at very low temperature. The structural reorganizations related to the light‐induced and thermally induced LS–HS transitions were characterized by single‐crystal X‐ray diffraction below the relaxation temperature (T = 15K < T<sub>LIESST</sub>) and at 130K within the thermal hysteresis loop. We show that the LIESST and thermal spin transitions lead to the same structural variations, namely an elongation of the Fe–N bonds by 0.18Å (Fe–N<sub>NCS</sub>) and 0.20 Å (Fe–N<sub>btr</sub>), on going from LS to HS, together with a reorientation of the NCS group by nearly 13°. The atomic displacement amplitudes, derived from the crystal structures, indicate lattice vibration modes of larger amplitudes and correlatively lower vibration frequencies in the HS state. The deformation of the crystal lattice as a function of temperature and laser excitation was quantitatively analyzed in terms of the HS and LS thermal‐expansion (α<sub>HS</sub> and α<sub>LS</sub>) and spin‐transition spontaneous‐strain (ϵ) tensors. The eigendirections and eigenvalues of the α and ϵ tensors correlate well with the weak and strong interactions in the solid and are responsible for the high cooperativity and low‐dimensional behaviour. Magnetic and spectroscopic measurements were performed in all the different spin states and related to the structural findings.
dc.language.isoen
dc.publisherWiley-VCH Verlag
dc.subject.enPhotoswitching
dc.subject.enIron(II)
dc.subject.enStructural analysis
dc.subject.enPhotomagnetism
dc.subject.enSpin crossover
dc.title.enOptical, Magnetic and Structural Properties of the Spin‐Crossover Complex [Fe(btr)<sub>2</sub>(NCS)<sub>2</sub>]·H<sub>2</sub>O in the Light‐Induced and Thermally Quenched Metastable States
dc.typeArticle de revue
dc.identifier.doi10.1002/ejic.200700872
dc.subject.halSciences de l'ingénieur [physics]/Mécanique [physics.med-ph]
dc.subject.halSciences de l'ingénieur [physics]/Matériaux
bordeaux.journalEuropean Journal of Inorganic Chemistry
bordeaux.page5693-5706
bordeaux.volume36
bordeaux.peerReviewedoui
hal.identifierhal-01007184
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-01007184v1
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