title: A Strongly Spin-Frustrated Fe(III) 7 Complex with a Canted Intermediate Spin Ground State of S=7/2 or 9/2.
abstract: A disk-shaped [Fe(III) 7 (Cl)(MeOH)6 (μ3 -O)3 (μ-OMe)6 (PhCO2 )6 ]Cl2 complex with C3 symmetry has been synthesised and characterised. The central tetrahedral Fe(III) is 0.733 Å above the almost co-planar Fe(III) 6 wheel, to which it is connected through three μ3 -oxide bridges. For this iron-oxo core, the magnetic susceptibility analysis proposed a Heisenberg-Dirac-van Vleck (HDvV) mechanism that leads to an intermediate spin ground state of S=7/2 or 9/2. Within either of these ground state manifolds it is reasonable to expect spin frustration effects. The (57) Fe Mössbauer (MS) analysis verifies that the central Fe(III) ion easily aligns its magnetic moment antiparallel to the externally applied field direction, whereas the other six peripheral Fe(III) ions keep their moments almost perpendicular to the field at stronger fields. This unusual canted spin structure reflects spin frustration. The small linewidths in the magnetic Mössbauer spectra of polycrystalline samples clearly suggest an isotropic exchange mechanism for realisation of this peculiar spin topology.
authors.affiliation: Institut für Anorganische Chemie, Karlsruher Institut für Technologie, Engesserstr. 15, 76131 Karslruhe (Germany).
authors.forename: Kartik Chandra
authors.initials: KC
authors.lastname: Mondal
authors.affiliation: Institut für Anorganische Chemie, Karlsruher Institut für Technologie, Engesserstr. 15, 76131 Karslruhe (Germany).
authors.forename: Valeriu
authors.initials: V
authors.lastname: Mereacre
authors.affiliation: Institut für Nanotechnologie, Karlsruher Institut für Technologie, Herrmann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany).
authors.forename: George E
authors.initials: GE
authors.lastname: Kostakis
authors.affiliation: Institut für Anorganische Chemie, Karlsruher Institut für Technologie, Engesserstr. 15, 76131 Karslruhe (Germany).
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Lan
authors.affiliation: Institut für Anorganische Chemie, Karlsruher Institut für Technologie, Engesserstr. 15, 76131 Karslruhe (Germany).
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Anson
authors.affiliation: WMOSS.ORG, Max-Beckmann-Str. 29, 76227, Karlsruhe (Germany). pion@wmoss.org.
authors.forename: Ion
authors.initials: I
authors.lastname: Prisecaru
authors.affiliation: Physikalisches Institut, Universität Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg (Germany). oliver.waldmann@physik.uni-freiburg.de.
authors.forename: Oliver
authors.initials: O
authors.lastname: Waldmann
authors.affiliation: Institut für Anorganische Chemie, Karlsruher Institut für Technologie, Engesserstr. 15, 76131 Karslruhe (Germany). annie.powell@kit.edu.|Institut für Nanotechnologie, Karlsruher Institut für Technologie, Herrmann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany). annie.powell@kit.edu.
authors.forename: Annie K
authors.initials: AK
authors.lastname: Powell
keywords: Mössbauer spectroscopy; magnetic properties; polynuclear iron complexes; spin frustration