Abstract
The ferrocenyl 1,2-diketone [ (C
5H
5)Fe (C
5H
4)COCOPh] when condensed with aromatic 1,2-diamines forms a range of ferrocenyl-substituted quinoxalines: when the diamine is unsymmetrically substituted the quinoxaline is formed as a mixture of two regio-isomers, which can in some cases be separated by careful chromatography. Electrochemical studies show that these present ferrocenylquinoxalines undergo the expected reversible one-electron oxidation centred on the ferrocenyl moiety and a two-electron reduction process centred on the quinoxalyl fragment, which is accompanied by chemical complications. The oxidation of the ferrocenyl group occurs at potentials slightly higher than that of unsubstituted ferrocene (by about 100–150 mV, depending on the substituents) indicating that the quinoxalyl substituent is slightly electron-withdrawing with respect to ferrocene.