Voltammetry of some novel Fe(III) complexes with tetradentate ONNO ligands. The axial ligand effect

Abstract

The electrochemistry of some novel Fe(III) complexes of the type Fe(L)Cl involving several tetradentate ligands based on the bis-condensation products of S-methylisothiosemicarbazide with two either identical or different aldehydes (salicylaldehyde, its derivatives, or 2-hydroxy-1-naphthaldehyde), was studied in DMF solutions at a GC electrode. All complexes undergo a two-step one-electron reduction which is usually complicated by chemical reactions. In solutions containing Cl- (either from the complex, or added as LiCl), the Cl--DMF ligand exchange reaction takes place and is especially pronounced for the Fe(II) oxidation state. The stability of the chloride-containing complexes was discussed in detail in view of the coordinated ligand effect and the oxidation state of the central atom. Some relevant kinetic parameters are calculated. © 1988.