Electrochemical properties of [FeIII(L)2Cl2] [PF6] and [Fe2III,IIIO(L)4Cl2] [PF6]2 [L=2,2′-bipyridine (bpy) and 4,4′-dimethyl-2,2′-bipyridine (dmbpy)].: Crystal structures of the dmbpy derivatives

The electrochemical behaviour of the iron(III) complexes [Fe(L)(2)Cl-2](+) and [Fe2O(L)(4)Cl-2](2+) [L = 2,2'-bipyridine (bpy) and 4,4'-dimethyl-2,2'-bipyridine (dmbpy)] has been investigated in acetonitrile. Their reduction leads to the iron(II) complex ion [Fe(L)(3)](2+), accompanied by the release of Cl- ions and the formation of [FeCl4](-) ions or by the formation of an unidentified Fe(III) chloro oxide, depending on the starting complex. These two new chloro complexes can be further reduced into Fe(II) species at a more negative potential. In addition, it has been shown that [Fe(L)(2)Cl-2](+) can be obtained in good yield via the electrochemical oxidation of [Fe(L)(3)](2+) in the presence of free Cl- anions, at least for L = dmbpy. The crystal structure of the new mono- and binuclear dmbpy complexes has been determined by X-ray diffraction.