Synthesis and characterization of a novel oxovanadium(IV) complex and conductometric studies with N,N '-bis(salicylidene)-1,2-bis-(p-aminophenoxy)ethane

Abstract

A new oxovanadium complex of the Schiff base obtained by the condensation of 1,2-bis(p-aminophenoxy)ethane with salicylaldehyde was synthesized. The complex has been characterized by elemental analyses, magnetic measurements, UV-VIS and IR spectra. Stability constants and thermodynamic values for complexation between Cu(NO3)(2), Zn(NO3)(2).6H(2)O, and VOSO4.5H(2)O salts and the ligand synthesized by the method described in the literature in 80% dioxane-water and pure methanol were determined by conductance measurements. The stability constants (log K-c) in 80% dioxane/water decrease in the order Cu(II) > (Zn(II). However, just the opposite behavior has been obtained for these metal complexes with the ligand in methanol (Zn(II) > (Cu(II)). The magnitudes of these ion association constants are related to the nature of solvation of the cation and of the complexed cation. The mobility of the complexes is also dependent, in part, upon solvation effects. Since the mobility of the VO(IV)L complex has been found to be higher than that of VO(IV) ion, assuming that the complex-solvent interaction in the VO(IV)-L systems is comparatively weak. A major consequence of the complexation is the increase in the molar conductivity of the complex and a corresponding large decrease in kappa values. For this reason, it was not obtained any stability constant values for VO(IV)-L systems in two type of solvents.