Determination of the Stability Constants for some First Transition Elements Complexes with 3-(2- hydroxyl phenyl ) -2 – Pyrazoline In Aqueous Solution

Abstract

Transition metal complexes Cr(III) , Fe(III) , Co(II) , Ni(II) & Cu(II) with 3-(2- hydroxy phenyl ) -2– pyrazoline have been prepared and characterized in aqueous solution. The complexes were characterized by infrared (IR), UV-visible & molar conductivity measurements. The bidentate ligand was bonded from one of the nitrogen atoms of pyrazolien & oxygen atom phenoxide group. The molecular structure for the complexes was proposed. The stability constants of these complexes were found by measuring electric molar conductivity in different concentrations was also found. The determined values of the prepared complexes increases according to the following sequence:Co+2 > Cu+2 > Ni+2 > Fe+3 > Cr+3This result agrees with the Irving Williamson series:-Mn+2 < Fe+2 < Co+2 < Ni+2 < Cu+2 > Zn+2