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dc.contributor.authorEames, Emily V.
dc.contributor.authorHarris, T. David
dc.contributor.authorBetley, Theodore A
dc.date.accessioned2014-10-14T19:38:43Z
dc.date.issued2012
dc.identifier.citationEames, Emily V., T. David Harris, and Theodore A. Betley. 2012. “Modulation of Magnetic Behavior via Ligand-Field Effects in the Trigonal Clusters (PhL)Fe3L*3 (L* = Thf, Py, PMe2Ph).” Chemical Science 3, no. 2: 407-415.en_US
dc.identifier.issn2041-6520en_US
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:13041316
dc.description.abstractUtilizing a hexadentate ligand platform, a series of trinuclear iron clusters (PhL)Fe3L*3 (PhLH6 1⁄4 MeC (CH2NPh-o-NPh)3; L* 1⁄4 tetrahydrofuran (1), pyridine (2), PMePh2 (3)) has been prepared. The phenyl substituents on the ligand sterically prohibit strong iron–iron bonding from occurring but maintain a sufficiently close proximity between iron centers to permit direct interactions. Coordination of the weak-field tetrahydrofuran ligand to the iron centers results in a well-isolated, high-spin S 1⁄4 6 or S 1⁄4 5 ground state, as ascertained through variable-temperature dc magnetic susceptibility and low- temperature magnetization measurements. Replacing the tetrahydrofuran ligands with stronger s-donating pyridine or tertiary phosphine ligands reduces the ground state to S 1⁄4 2 and gives rise to temperature-dependent magnetic susceptibility. In these cases, the magnetic susceptibility cannot be explained as arising simply from superexchange interactions between metal centers through the bridging amide ligands. Rather, the experimental data are best modelled by considering a thermally- induced variation in molecular spin state between S 1⁄4 2 and S 1⁄4 4. Fits to these data provide thermodynamic parameters of DH 1⁄4 406 cm 1 and Tc 1⁄4 187 K for 2 and DH 1⁄4 604 cm 1 and Tc 1⁄4 375 K for 3. The difference in these parameters is consistent with ligand field strength differences between pyridine and phosphine ligands. To rationalize the spin state variation across the series of clusters, we first propose a qualitative model of the Fe3 core electronic structure that considers direct Fe–Fe interactions, arising from direct orbital overlap. We then present a scenario, consistent with the observed magnetic behaviour, in which the s orbitals of the electronic structure are perturbed by substitution of the ancillary ligands.en_US
dc.description.sponsorshipChemistry and Chemical Biologyen_US
dc.language.isoen_USen_US
dc.publisherRoyal Society of Chemistry (RSC)en_US
dc.relation.isversionofdoi:10.1039/c1sc00492aen_US
dash.licenseLAA
dc.titleModulation of magnetic behavior via ligand-field effects in the trigonal clusters (PhL)Fe3L*3 (L* = thf, py, PMe2Ph)en_US
dc.typeJournal Articleen_US
dc.description.versionVersion of Recorden_US
dc.relation.journalChem. Sci.en_US
dash.depositing.authorBetley, Theodore A
dc.date.available2014-10-14T19:38:43Z
dc.identifier.doi10.1039/c1sc00492a*
dash.contributor.affiliatedBetley, Theodore


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