New family of ferric spin clusters incorporating redox-active ortho-dioxolene ligands.

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dc.contributor.authorMulyana, Yen_AU
dc.contributor.authorNafady, Aen_AU
dc.contributor.authorMukherjee, Aen_AU
dc.contributor.authorBircher, Ren_AU
dc.contributor.authorMoubaraki, Ben_AU
dc.contributor.authorMurray, KSen_AU
dc.contributor.authorBond, AMen_AU
dc.contributor.authorAbrahams, BFen_AU
dc.contributor.authorBoskovic, Cen_AU
dc.date.accessioned2009-08-20T05:12:08Zen_AU
dc.date.accessioned2010-04-30T05:04:46Zen_AU
dc.date.available2009-08-20T05:12:08Zen_AU
dc.date.available2010-04-30T05:04:46Zen_AU
dc.date.issued2009-08-17en_AU
dc.date.statistics2009-08-17en_AU
dc.description.abstractSeven new di-, tri-, tetra-, and hexanuclear iron complexes that incorporate a polydentate Schiff base and variously substituted catecholate ligands have been synthesized from the trinuclear precursor [Fe3(OAc)3(L)3] (1), where LH2 = 2-[[(2-hydroxyethyl)imino]phenylmethyl]-phenol. These were isolated as the compounds [Fe3(OAc)(Cat)(L)3] (2), [Fe6(OAc)2(Cat)4(L)4] (3), [Fe4(3,5-DBCat)2(L)4] (4), [Bu4N][Fe4(OAc)(3,5-DBCat)4(L)2] (5a, 5- is the complex monoanion [Fe4(OAc)(3,5-DBCat)4(L)2]-), [Fe4(OAc)(3,5-DBCat)3(3,5-DBSQ)(L)2] (6), [Fe2(Cl4Cat)2(L)(LH2)(H2O)] (7), and [Et3NH]2[Fe2(Cl4Cat)2(L)2] (8a, 8²- is the complex dianion [Fe2(Cl4Cat)2(L)2]2-), where CatH2 = catechol; 3,5- DBCatH2 = 3,5-di-tert-butyl-catechol; 3,5-DBSQH = 3,5-di-tert-butyl-semiquinone, and Cl4CatH2 = tetrachlorocatechol. While compounds 2-4, 5a, 7, and 8a were obtained by directly treating 1 with the appropriate catechol, compound 6 was synthesized by chemical oxidation of 5a. These compounds have been characterized by single crystal X-ray diffraction, infrared and UV-visible spectroscopy, voltammetry, UV-visible spectroelectrochemistry, andmagnetic susceptibility and magnetization measurements. An electrochemical study of the three tetranuclear complexes (4, 5-, and 6) reveals multiple reversible redox processes due to the o-dioxolene ligands, in addition to reductive processes corresponding to the reduction of the iron(III) centers to iron(II). A voltammetric study of the progress of the chemical oxidation of compound 5a, together with a spectroelectrochemical study of the analogous electrochemical oxidation, indicates that there are two isomeric forms of the one-electron oxidized product. A relatively short-lived neutral species (5) that possesses the same ligand arrangement as complex 5- is the kinetic product of both chemical and electrochemical oxidation. After several hours, this species undergoes a significant structural rearrangement to convert to complex 6, which appears to be largely driven by the preference for the 3,5-DBSQ- ligand to bind in a non-bridging mode. Variable temperature magnetic susceptibilitymeasurements for compounds 3, 4, 5a, 6, 7, and8a reveal behavior dominated by pairwise antiferromagnetic exchange interactions, giving rise to a poorly isolated S = 0 ground state spin for compound 3, well-isolated S = 0 ground state spins for complexes 4, 5-, 7 and 8²-, and a well-isolated S = 1/2 ground state spin for complex 6. The ground state spin values were confirmed by low temperature variable field magnetization measurements. The thermal variation of the magnetic susceptibility for compounds 3, 4, 5a, 6, 7, and 8a were fitted and/or simulated using the appropriate Hamiltonians to derive J values that are consistent with magnetostructural correlations that have been reported previously for alkoxobridged ferric complexes. © 2009, American Chemical Societyen_AU
dc.identifier.citationMulyana, Y., Nafady, A., Mukherjee, A., Bircher, R., Moubaraki, B., Murray, K. S., Bond, A. M., Abrahams, B. F., & Boskovic, C. (2009). New family of ferric spin clusters incorporating redox-active ortho-dioxolene ligands. Inorganic Chemistry, 48(16), 7765-7781. doi:10.1021/ic900729den_AU
dc.identifier.govdoc1311en_AU
dc.identifier.issn0020-1669en_AU
dc.identifier.issue16en_AU
dc.identifier.journaltitleInorganic Chemistryen_AU
dc.identifier.pagination7765-7781en_AU
dc.identifier.urihttp://dx.doi.org/10.1021/ic900729den_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/1692en_AU
dc.identifier.volume48en_AU
dc.language.isoenen_AU
dc.publisherAmerican Chemical Societyen_AU
dc.subjectMagnetic propertiesen_AU
dc.subjectLigandsen_AU
dc.subjectCobalten_AU
dc.subjectIron compoundsen_AU
dc.subjectEnergy levelsen_AU
dc.subjectRedox processen_AU
dc.titleNew family of ferric spin clusters incorporating redox-active ortho-dioxolene ligands.en_AU
dc.typeJournal Articleen_AU
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