Stoichiometric study of metals salicylhydroxamate complexes

Abstract

Methyl salicylate was prepared by acid esterification of salicylic acid in methanol. Hydroxylamine hydrochloride was freed by neutralization with equi-molar amount of sodium hydroxide. Salicylhydroxamic acid was synthesized by coupling the prepared methylsalicylate with free hydroxylamine. The compound was identified and characterized by m.p. and IR spectroscopy. Iron, copper and vanadium complexes of salicylhydroxamic acid were prepared and showed their characteristic colors. UV-Vis spectrophotometric analysis of these complexes shows a linear relationship between the absorbance and complex concentration for these metal ions. Stoichiometry was investigated for the ligand with iron, copper, and vanadium at different pH’s to be found as 1:1, 1:2, and 1:3 for iron, 1:2, and 1:3 for vanadium and 1:1 only for copper. This may lead to the investigation of using salicylhydroxamic acid as chromogenic reagent for analytical spectrophotometric determination of copper and vanadium.