American Chemical Society
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Ligand-Centered Oxidation in a Diiron s-Indacene Complex

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journal contribution
posted on 2000-02-18, 00:00 authored by Paul Roussel, Douglas R. Cary, Stephen Barlow, Jennifer C. Green, François Varret, Dermot O'Hare
The reaction of 1,3,5,7 tetra-tert-butyl-s-indacene (Ic‘) with [Fe2(CO)9] gives the bimetallic complex [{Fe(CO)3}2Ic‘], 1, where the two Fe(CO)3 fragments are coordinated to the same face of the Ic‘ ligand. The cyclic voltammogram of 1 displays two quasi-reversible molecular oxidation waves and an irreversible molecular reduction wave. 1 can be chemically oxidized to its monocation with silver tetrafluoroborate. Comparison of the crystal structures of 1 and [{Fe(CO)3}2Ic‘]+[BF4]-·CH2Cl2, 2, shows little change in bond lengths on oxidation. Although, at first glance, 2 may appear to be an Fe0/FeI mixed-valence compound, Mössbauer and EPR spectroscopy suggest that that the ionized electron originates from a largely indacene-based orbital. The structural and spectroscopic features of 1 and 2 have been rationalized by density functional calculations and compared to those of related systems.