The coordination chemistry of manganese complexes has been the subject of extensive investigation in the past few decades. Most of the studies have aimed to understand the role of manganese in many metalloenzymes in terms of structure–function relationships. The importance of manganese in a number of biological systems, has stimulated the study of the chemistry of manganese(III) complexes [1-3]. Previously mononuclear manganese(III) complexes of formula [Mn(L)(X)(H2O)] and [Mn(L)(X)] (X = ClO4, F, Cl,Br, I, NCS, N3), derived from the Schiff bases of 5-bromosalicylaldehyde and different types of diamine (1,2-diaminoethane,1,2-diaminopropane, 1,3-diaminopropane and 1,4-diaminobutane), have been reported [4]. Here synthesis of new series of mononuclear manganese(III) complexes with [Mn(L)(X)(S)] formula while X = ClO4, Cl, Br, I, N3 and S= water, ethanol are reported. The Schiff bases ligands were derived from of 5-y-2-hydroxybenzaldehyde and 1,2-diaminobenzene while y = NO2, H, OMe, and Br. The synthesis methodology of these complexes is including two steps. The first, synthesis of Mn(II)-Saloph complex and then in-situe oxidation of manganese(II) to manganese(III) by hydrogen peroxide or air in present of mentioned counter ions. These complexes were characterized by IR, Mass spectroscopy and UV-Vis spectroscopy. Moreover we used cyclic voltammetry method for studying of counter ion effect on the electronic properties of manganese complexes on comparing with previous research data [4].
