Iron(III) aroylhydrazone complexes: Structure, electrochemical studies and catalytic activity in oxidation of olefins

Tridentate Schiff base ligands derived from aromatic aldehydes and benzhydrazide, and their iron complexes [Fe(L-1)(HL1)] 1, [Fe(HL1)Cl-2(CH3OH)]center dot(CH3OH) 2 and [Fe(HL2)Cl-2(H2O)] 3 have been prepared and characterized (H2L1 = (E)-N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide, H2L2 = (E)-N'-(5- bromo-2-hydroxybenzylidene)benzohydrazide). The crystal Structure of 2 has been determined. The electrochemical properties of these complexes have been investigated by cyclic voltammetric technique in acetonitrile solutions. Electrochemical studies have revealed qusi-reversibility for these compounds. The catalytic potential of these complexes has been tested for the oxidation of cyclooctene using tert-butylhydroperoxide (TBHP) as oxidant. The effects of the molar ratio of oxidant to Substrate, the temperature, the co-catalyst concentration and the solvent have been studied. Excellent selectivities have been obtained for the epoxidation of cyclohexene, cyclooctene, norbornene. cis- and trans-stilbene. (c) 2009 Elsevier B.V. All rights reserved.