A new class of ferromagnetically-coupled mixed valence vanadium(IV/V) polyoxometalates

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dc.contributor.authorManos, M. J.en
dc.contributor.authorTasiopoulos, A. L.en
dc.contributor.authorTolis, E. L.en
dc.contributor.authorLalioti, N.en
dc.contributor.authorWoollins, J. D.en
dc.contributor.authorSlawin, A. M. Z.en
dc.contributor.authorSigalas, M. P.en
dc.contributor.authorKabanos, T. A.en
dc.date.accessioned2015-11-24T16:56:35Z
dc.date.available2015-11-24T16:56:35Z
dc.identifier.issn0947-6539-
dc.identifier.urihttps://olympias.lib.uoi.gr/jspui/handle/123456789/10456
dc.rightsDefault Licence-
dc.subjectferromagnetismen
dc.subjectintermolecular interactionen
dc.subjectpolyoxometalatesen
dc.subjectuhf calculationsen
dc.subjectvanadiumen
dc.subjecthigh-spin moleculesen
dc.subjectbinuclear complexesen
dc.subjectmagnetostructural correlationsen
dc.subjectstructural-characterizationen
dc.subjectorbital interactionsen
dc.subjectlarge clustersen
dc.subjectmagnetsen
dc.subjectexchangeen
dc.subjectcrystalen
dc.subjectcoreen
dc.titleA new class of ferromagnetically-coupled mixed valence vanadium(IV/V) polyoxometalatesen
heal.abstractReaction of [V(VI)OCl(2)(thf)(2)] with a bidentate nitrogen-donor ligand (L: phen=1,10-phenanthroline, 5-mephen= 5-methyl-1,10-phenanthroline, bipy=2,2'-bipyridine, 5,5'-me(2)bipy=5,5'-dimethyl-2,2'-bipy) in methyl alcohol, in the presence of triethylamine, leads to the formation of hexameric [V(2)(IV)V(4)(V)] oxo-alkoxo-vanadates of the general formula [V(6)O(12)-(mu(2)-OCH(3))(4)(L)(4)].xH(2)O [L=phen (1 . 4H(2)O), 5-mephen (2 . 6H(2)O), bipy (3 . 4H(2)O), 5,5'-me(2)bipy (4 . H(2)O)]. X-ray structure analysis of 1 . 2H(2)O and 4. 8CH(3)OH revealed a pair Of V(3)O(13)N(4) trimeric units sharing two corners, with a centrosymmetric planar V(6)-core. In addition, a fully oxidized V(V) species [V(4)(V)O(8)(OCH(3))(2)(mu(3)-OCH(3))(2)(5,5'-me(2)bipy)(2)].3CH(3)OH (5 . 3CH(3)OH) was isolated from the reaction mixture used for the synthesis of 4 . H(2)O. The crystal structure of 5 . 3CH(3)OH revealed a dicubane-like framework with two missing vertices. Electron paramagnetic resonance (EPR) and variable temperature magnetic susceptibility studies for the hexamers 1 . 4 H(2)O and 3 . 4H(2)O showed the complete localization of the single 3d electrons on the V(IV) ions and unusual ferromagnetic interaction between the two paramagnetic vanadium(iv) ions separated by a distance of about 5.1 Angstrom. Furthermore, intermolecular antiferromagnetic interactions through pi-contacts of phenyl rings were observed for these species below 8 K. The ferromagnetic exchange coupling observed in the hexanuclear compounds 1.4H(2)O and 3.4 H(2)O is also discussed using ab initio UHF calculations on a model compound. The value of the exchange coupling constant (3.7 cm(-1)) for this model compound, calculated using the broken symmetry approach, is in good agreement, both in sign and magnitude, with the experimental J values (6.00 cm(-1) for 1.4H(2)O and 8.54 cm(-1) for 3.4H(2)O).en
heal.accesscampus-
heal.fullTextAvailabilityTRUE-
heal.identifier.primaryDOI 10.1002/chem.200390078-
heal.identifier.secondary<Go to ISI>://000180868800013-
heal.identifier.secondaryhttp://onlinelibrary.wiley.com/store/10.1002/chem.200390078/asset/695_ftp.pdf?v=1&t=hmu8zvrz&s=866f1fc7502e7b47b0c9f34717c2861e728fcb60-
heal.journalNameChemistry-a European Journalen
heal.journalTypepeer reviewed-
heal.languageen-
heal.publicationDate2003-
heal.publisherWiley-VCH Verlagen
heal.recordProviderΠανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείαςel
heal.typejournalArticle-
heal.type.elΆρθρο Περιοδικούel
heal.type.enJournal articleen

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