Synthesis and structure of an "iron-doped" copper selenide cluster molecule: [Cu30Fe2Se6(SePh)24(dppm)4]
Andreas Eichhöfer1, Jolanta Olkowska-Oetzel, Dieter Fenske
1Institut für Nanotechnologie, Forschungszentrum Karlsruhe, Postfach 3640, 76021 Karlsruhe, Germany. eichhoefer@int.fzk.de
Abstract:
CuCl and bis(diphenylphosphanyl)methane (dppm) react in the presence of small amounts of FeCl(3) with PhSeSiMe(3) and Se(SiMe(3))(2) to yield [Cu(30)Fe(2)Se(6)(SePh)(24)(dppm)(4)]. The crystal structure of the compound was determined by single-crystal X-ray analysis to give a mixed copper selenide/selenolate cluster molecule of a new structural type incorporating two central iron atoms. The formal oxidation state of the iron atoms was determined by Mössbauer spectroscopy to be +3, in agreement with quantum chemical calculations and modeling of the magnetic data. In addition, Mössbauer studies show no magnetic hyperfine structure in zero field, and the magnetically perturbed spectrum displays a pattern typical for a diamagnetic species in a transverse field, suggesting a singlet ground state. However, the inclusion of the iron atoms has a distinct influence on the optical properties of the compound compared to similar clusters containing only copper and selenium atoms.
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