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Cooperative iron(II) spin crossover complexes with N4O2 coordination sphere

hal.structure.identifierDepartment of Chemistry and Biochemistry
dc.contributor.authorWEBER, Birgit
hal.structure.identifierDepartment of Chemistry and Biochemistry
dc.contributor.authorKAPS, Eike
hal.structure.identifierDepartment of Chemistry and Biochemistry
dc.contributor.authorWEIGAND, Jan
hal.structure.identifierInstitut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
dc.contributor.authorCARBONERA, Chiara
hal.structure.identifierInstitut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
dc.contributor.authorLÉTARD, Jean-François
hal.structure.identifierDepartment of Physics
dc.contributor.authorACHTERHOLD, Klaus
hal.structure.identifierDepartment of Physics
dc.contributor.authorPARAK, Fritz G.
dc.date.issued2008
dc.identifier.issn0020-1669
dc.description.abstractEnTwo new spin crossover complexes [FeL(py)2] (1) and [FeL(DMAP)2] (2) with L being a tetradentate N2O22- coordinating Schiff-base-like ligand [([3,3']-[1,2-phenylenebis(iminomethylidyne)]bis(2,4-pentanedionato)(2-)-N,N',O2,O2'], py = pyridine and DMAP = p-dimethylaminopyridine have been investigated using temperature-dependent susceptibility and thermogravimetric and photomagnetic measurements as well as Mössbauer spectroscopy and X-ray structure analysis. Both complexes show a cooperative spin transition with an approximately 9 K wide thermal hysteresis loop in the case of 2 (T1/2 = 183 K and T1/2 = 174 K) and an approximately 2 K wide thermal hysteresis loop in the case of the pyridine diadduct 1 (T1/2 = 191 K and T1/2 = 189 K). The spin transition was additionally followed by different temperature-scanning calorimetry and Mössbauer spectroscopy for 2, and a good agreement for the transition temperatures obtained with the different methods was found. Results from X-ray structure analysis indicate that the cooperative interactions are due to elastic interactions in both compounds. They are more pronounced in the case of 2 with very short intermolecular iron-iron distances of 7.2 Å and several intense C-C contacts. The change of the spin state at the iron center is accompanied by a change of the O-Fe-O angle, the so-called bit of the equatorial ligand, from 108 in the high-spin state to 90 in the low-spin state. The reflectivity measurements of both compounds give at low temperature indication that at the sample surface the light-induced excited spin state trapping (LIESST) effect occurs. In bulk condition using a SQUID magnetometer the complex 2 displays some photomagnetic properties with an photoexcitation level of 60% and a T(LIESST) value of 53 K.
dc.language.isoen
dc.publisherAmerican Chemical Society
dc.subject.enInorganic compounds
dc.subject.enN4O2
dc.subject.enSpin crossover
dc.subject.enSphere
dc.subject.enIron(II)
dc.title.enCooperative iron(II) spin crossover complexes with N4O2 coordination sphere
dc.typeArticle de revue
dc.identifier.doi10.1021/ic070067o
dc.subject.halChimie/Matériaux
bordeaux.journalInorganic Chemistry
bordeaux.page487-496
bordeaux.volume47
bordeaux.issue2
bordeaux.peerReviewedoui
hal.identifierhal-00258997
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-00258997v1
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