Structural Characterization and Electrochemical Study of Novel Ferrocene Derivatives Prepared from [(β-Ferrocenylvinyl)imino]phosphorane by Aza Wittig Reactions

Abstract

A rapid and efficient synthetic procedure has been developed to prepare new ferrocene derivatives such as β-ferrocenylvinyl heterocumulenes and ferrocene-containing imidazole ring bearing one, two, or three ferrocene subunits. The method is based on the aza Wittig reaction of [(β-ferrocenylvinyl)imino]phosphorane 3, readily available from ferrocenecarboxaldehyde by sequential treatment with ethyl azidoacetate and triphenylphosphine, with isocyanates and further treatment with the appropriate primary amine. The crystal structures of compounds 6c (monoferrocene derivative), 11c, and 12b (biferrocene derivatives) have been determined by single-crystal X-ray methods. The electrochemical properties of these new compounds are also reported.