Redox behaviour of ([fc( NPiPr2) 2] Fe) 2, formation of an iron- iron bond and cleavage of azobenzene

The redox behaviour of the dimeric tetrairon complex, ({[}fc((NPPr2)-Pr-i)(2)]Fe)(2) (where fc((NPPr2)-Pr-i)(2) = 1,1-((C5H4NPPr2)-Pr-i)(2)Fe) has been investigated. Upon reduction with KC8 an Fe-Fe bond is formed with the complex maintaining a high spin configuration and having the formula {[}K(THF)(6)]({[}fc((NPPr2)-Pr-i)(2)]Fe)(2). In contrast, oxidation of the complex is ligand based; for example, addition of the 1,2-diiodoethane (I-2 equivalent) results in the formation of the monomeric iron(ii) diiodide {[}fc((NPr2I)-Pr-i)(2)]FeI2 wherein the phosphine is oxidized. The dimeric tetrairon complex reacts photolytically with azobenzene, cleaving the N?N double bond and forming the new monomeric bis(phosphoramidate) iron complex. {[}fc(NP(NPh)Pr-i(2))(2)]Fe. Characterization of these paramagnetic complexes was accomplished by magnetic susceptibility studies and X-ray analyses.