Studies of an Fe9 tridiminished icosahedron

Evangelos I. Tolis, Larry P. Engelhardt, Pamela V. Mason, Gopalan Rajaraman, Koichi Kindo, Marshall Luban, Akira Matsuo, Hiroyuki Nojiri, James Raftery, Christian Schröder, Grigore A. Timco, Floriana Tuna, Wolfgang Wernsdorfer, Richard E.P. Winpenny

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59 Citations (Scopus)


The synthesis and structural characterization of a nonanuclear Fe III cage complex is reported. The nine iron centers in [Fe 93-O)4(O3PPh)3- (O2CCMe3)13] lie on the vertices of an incomplete icosahedron, with the P atoms of triphenylphosphonate at the other three vertices. The paramagnetic core therefore describes a tridiminished icosahedron. Magnetic studies suggest an S=1/2 ground state for the molecule. Analysis of exchange paths and the susceptibility data point to the interpretation that the cluster can be divided into two nearly decoupled sections: an {Fe6O33) section, with an 5 = 0 ground state, in which three oxo-centered triangles bound a central triangle that is not oxo-centered; and an {Fe3O} triangle with S = 1/2. The analysis of the susceptibility data leads to a Heisenberg model based on three significant antiferromagnetic exchange inter actions, with values of 173.7 cm-1 in the {Fe3O} triangle, and 30.9 and 19.1 cm-1 within the {Fe6O3} section, while the exchange between them is <1 cm-1. With these assignments, the theoretical low-temperature differential susceptibility is also in very good agreement with measurements up to 50 T. Magnetic measurements in the milli-kelvin range reveal striking hysteresis loops and magnetization reversals associated with a Landau-Zener-Stückelberg (LZS) transition as enhanced by the occurrence of a phonon bottleneck.

Original languageEnglish
Pages (from-to)8961-8968
Number of pages8
JournalChemistry - A European Journal
Issue number35
Publication statusPublished - 2006 Dec 4


  • Cage compounds
  • Iron
  • Molecular magnetism
  • Phosphonate ligands
  • X-ray diffraction


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