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Mass Effect on the Equienergetic High-Spin/Low-Spin States of Spin-Crossover in 4,4'-Bipyridine-Bridged Iron(II) Polymeric Compounds: Synthesis, Structure, and Magnetic, Mössbauer, and Theoretical Studies

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Mass Effect on the Equienergetic High-Spin/Low-Spin States of Spin-Crossover in 4,4'-Bipyridine-Bridged Iron(II) Polymeric Compounds: Synthesis, Structure, and Magnetic, Mössbauer, and Theoretical Studies

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dc.contributor.author Moliner, N. es_ES
dc.contributor.author Muñoz Roca, María Del Carmen es_ES
dc.contributor.author Létard, S. es_ES
dc.contributor.author Salmon, L. es_ES
dc.contributor.author Tuchagues, J. P. es_ES
dc.contributor.author Bousseksou, A. es_ES
dc.contributor.author Real, J. A. es_ES
dc.date.accessioned 2020-04-17T12:50:35Z
dc.date.available 2020-04-17T12:50:35Z
dc.date.issued 2002-12-30 es_ES
dc.identifier.issn 0020-1669 es_ES
dc.identifier.uri http://hdl.handle.net/10251/140921
dc.description.abstract [EN] The suitability of the system [Fe(4,4`-bipy)(H2O)2(NCX)2]·(4,4`-bipy), where 4,4`-bipy stands for 4,4`-bipyridine and X = S (1) and Se (2), as a precursor for the synthesis of new polymeric spin-crossover compounds has been studied. The reaction of 1 or 2 with bt (2,2`-bithiazoline) afforded the polymeric compounds of formula [Fe(4,4`-bipy)(bt)(NCX)2] (X = S (3), Se (4)). Compounds 3 and 4 are isostructural, but only the crystal structure of 3 has been fully determined. It crystallizes in the orthorhombic system, Fdd2 space group, Z = 24, with a = 38.962(8) Å, b = 11.545(2) Å, c = 30.889(6) Å, V = 13895(5) Å3. The structure consists of linear chains constituted by trans-4,4`-bipy linked iron(II) ions; two cis equatorial positions are occupied by two pseudohalide ligands, and the remaining positions are filled by the bidentate bt ligand. Investigation of their magnetic properties and Mössbauer spectra has revealed the occurrence of a low-spin (LS) ¿ high-spin (HS) conversion involving 12% (3, S) and 20% (4, Se) of the Fe(II) ions. The thermal variation of the HS fraction is gradual with onset temperatures as low as 60 K. A theoretical approach based on the Ising-like model, completed with molecular vibrations, through harmonic oscillators, fits the data successfully, leading to an energy gap of 65 cm-1 (3) and 86 cm-1 (4) between the lowest LS and HS levels, and an average vibration frequency ¿¿LS of 382 cm-1 (3) and 365 cm-1 (4) in the LS state. The ca. 1.05 ¿LS(3)/¿LS(4) ratio is close to the ca. 1.09 Se/S molar mass ratio. The simple electrovibrational Ising-like model permits us to explain, for the first time, a mass effect through the molecular vibrations in a spin-crossover complex that is in the unusual situation of equienergy among the HS and LS states. es_ES
dc.description.sponsorship We thank the financial assistance from the Ministerio Español de Ciencia y Tecnología (Project BQU 2001-2928). We acknowledge the European Commission for granting the TMR-Network Thermal and Optical Switching of Molecular Spin States (TOSS) , Contract noERB-FMRX-CT98-0199EEC/TMR. es_ES
dc.language Inglés es_ES
dc.publisher American Chemical Society es_ES
dc.relation EC/ERB-FMRX-CT98-0199EEC/TMR es_ES
dc.relation Ministerio de Ciencia y Tecnología/BQU2001-2928 es_ES
dc.relation.ispartof Inorganic Chemistry es_ES
dc.rights Reserva de todos los derechos es_ES
dc.subject.classification FISICA APLICADA es_ES
dc.title Mass Effect on the Equienergetic High-Spin/Low-Spin States of Spin-Crossover in 4,4'-Bipyridine-Bridged Iron(II) Polymeric Compounds: Synthesis, Structure, and Magnetic, Mössbauer, and Theoretical Studies es_ES
dc.type Artículo es_ES
dc.identifier.doi 10.1021/ic0203825 es_ES
dc.rights.accessRights Cerrado es_ES
dc.contributor.affiliation Universitat Politècnica de València. Departamento de Física Aplicada - Departament de Física Aplicada es_ES
dc.description.bibliographicCitation Moliner, N.; Muñoz Roca, MDC.; Létard, S.; Salmon, L.; Tuchagues, JP.; Bousseksou, A.; Real, JA. (2002). Mass Effect on the Equienergetic High-Spin/Low-Spin States of Spin-Crossover in 4,4'-Bipyridine-Bridged Iron(II) Polymeric Compounds: Synthesis, Structure, and Magnetic, Mössbauer, and Theoretical Studies. Inorganic Chemistry. 41(26):6997-7005. https://doi.org/10.1021/ic0203825 es_ES
dc.description.accrualMethod S es_ES
dc.relation.publisherversion https://doi.org/10.1021/ic0203825 es_ES
dc.description.upvformatpinicio 6997 es_ES
dc.description.upvformatpfin 7005 es_ES
dc.type.version info:eu-repo/semantics/publishedVersion es_ES
dc.description.volume 41 es_ES
dc.description.issue 26 es_ES
dc.relation.pasarela S\22016 es_ES
dc.contributor.funder European Commission es_ES
dc.contributor.funder Ministerio de Ciencia y Tecnología es_ES


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