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DOI: 10.1039/A809710K (Paper) Reference Section for: J. Chem. Soc., Dalton Trans., 1999, 957-964

Exo-iron centres linked to MoFeS clusters

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Frédéric Barrière, David J. Evans, David L. Hughes, Saad K. Ibrahim, Jean Talarmin and Christopher J. Pickett

Abstract

Monocubane clusters with exo-iron atoms were synthesized from the iron-bridged dicubane [NEt4]3[Mo2Fe7S8(SEt)12] by reactions with π-acid ligands. The structures of two derivatives, [NEt4][MoFe3S4X3(µ-SEt)3Fe(CNtBu)3], X = Cl or PhS, have been established by X-ray crystallography. Electrochemical and Mössbauer data showed that the cubane core retains the {MoFe3S4}3+ redox level of the parent material and that the exo-iron centre is in the low-spin iron(II) state. Infrared and electrochemical data showed that there is little electronic interaction between the cubane and exo-iron centres. The parent complex possesses a low-spin bridging iron(III) centre. This centre undergoes slow electron transfer which is ascribed to spin-state reorganisation to high-spin FeII. Reduction of the cubane units leads to reversible deco-ordination of a bridging thiolate group from a molybdenum centre.

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