Jean-Claude Leprêtre

Chemical and electrochemical generation of [Fe(bpy)2(S)2]2+ (bpy=2,2′-bipyridine, S=H2O or CH3CN). A route for synthesis of coordinatively dissymmetrical iron(II) polypyridine complexes and supramolecular structures containing a Fe(bpy)32+ moiety

A n route for the synthesis of coordinatively dissymmetrical iron(II) polypyridine complexes [Fe(L)2L′]2+ (L and L′ are n two different 2,2′-bipyridine derivatives) is described. The procedure is based on the use of the precursor [Fe(L)2(CH3CN)2]2+ n (L=2,2′-bipyridine), which can be easily prepared by electrochemical or chemical reduction of the μ-oxo diaqua diiron(III) complex [Fe2O(bpy)4(H2O)2]4+ in acidic CH3CN solution. In addition, it is shown that this procedure n can be applied with success to the synthesis of covalently linked heterodinuclear complexes containing, for instance, Fe(bpy)32+ and Ru(bpy)32+ n moieties. n The electrochemical behaviour of all these new complexes is reported.

Electrochemical behaviour of hypocrellin A in acetonitrile and aqueous micellar media

The n electrochemical behaviour of hypocrellin A (HAH2) has been studied in acetonitrile and in aqueous micellar media. n In acetonitrile (CH3CN) the two successive one-electron transfers are reversible on the cyclic voltammetry time n scale and allow different reduced forms of HAH2 to be produced by exhaustive electrolysis. In addition, n the one-electron reduction of HAH2 has been studied by UV-visible and EPR spectroscopy, showing that the n one-electron transfer is associated with a protonation phenomenon leading to the formation of HAH2•− and HAH3•. In an aqueous n micellar medium the first reduction step behaves similarly to that in an organic medium and has allowed us n to establish the influence of the pH value on E1/2 and to determine the two pKa values of n HAH2 n, while n pKa values of the one-electron reduced forms of HAH2 have been evaluated.