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Stepwise spin transition in a mononuclear iron(II) complex with unusually wide plateau

hal.structure.identifierDepartment of Chemistry and Biochemistry
dc.contributor.authorWEBER, Birgit
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.authorDESPLANCHES, Cédric
hal.structure.identifierInstitut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
dc.contributor.authorLÉTARD, Jean-François
dc.date.issued2008
dc.identifier.issn1434-1948
dc.description.abstractEnThe reaction of the Schiff-base like ligand H2L [L2- = (E,E)-({diethyl 2,2-[1,2-phenylenebis(iminomethylidyne)]bis(3-oxobutanato)})] with iron(II) acetate in methanol in the presence of 4-cyanopyridine leads to the formation of an octahedral iron(II) complex with the formula FeL(CNpy)2·0.25CNpy (1). The magnetic properties of this complex were investigated using temperature-dependent susceptibility measurements (SQUID) and Mössbauer spectroscopy. Both measurements indicate that the complex performs a stepwise spin transition with a large plateau in the region from 225 K to 125 K and HS 0.25. The molecule structure of the compound was determined at room temperature, 240 K (HS 0.5 according to susceptibility measurements) and 100 K. Two complex molecules were found in the asymmetric unit with strong - interactions between the phenylene rings of H2L. In agreement with outcomes from the magnetic measurements, both iron centres are in the high-spin state at room temperature and in the low-spin state at 100 K. At 240 K one of the two iron centres is high-spin and the other one low-spin. The reason for the wide step with one fourth of the iron centres in the high-spin state is the additional distorted 4-cyanopyridine in the crystal that influences the transition temperature of the surrounding iron centres. The spin transition was followed in solution by using 1H NMR spectroscopy. A gradual spin transition with T1/2 = 238 K is obtained. Temperature-dependent diffuse reflectivity spectra show the occurrence of photoconversion at the surface of the sample but only about 6 % of the complex could be switched in bulk condition using a SQUID magnetometer and the stability of the photoinduced HS state with TLIESST = 40 K is very weak.
dc.language.isoen
dc.publisherWiley-VCH Verlag
dc.title.enStepwise spin transition in a mononuclear iron(II) complex with unusually wide plateau
dc.typeArticle de revue
dc.identifier.doi10.1002/ejic.200701216
dc.subject.halChimie/Matériaux
bordeaux.journalEuropean Journal of Inorganic Chemistry
bordeaux.page1589-1598
bordeaux.issue10
bordeaux.peerReviewedoui
hal.identifierhal-00295165
hal.version1
hal.popularnon
hal.audienceInternationale
dc.subject.itIron
dc.subject.itMagnetic properties
dc.subject.itSpin crossover
dc.subject.itPhotomagnetism
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-00295165v1
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=European%20Journal%20of%20Inorganic%20Chemistry&rft.date=2008&rft.issue=10&rft.spage=1589-1598&rft.epage=1589-1598&rft.eissn=1434-1948&rft.issn=1434-1948&rft.au=WEBER,%20Birgit&CARBONERA,%20Chiara&DESPLANCHES,%20C%C3%A9dric&L%C3%89TARD,%20Jean-Fran%C3%A7ois&rft.genre=article


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