5(4-dimethylaminobenzylidene) rhodanine as a reagent for the spectrophotometric determination of copper and manganese

Abstract

The synthesis and spectral characteristics of 5(4-dimethylaminobenzylidene) rhodanine have been investigated. The extraction-spectrophotometric method for the determination of copper and manganese based on their extraction into ethanol with 5(4-dimethylaminobenzylidene) rhodanine (DMABR) from a weakly acidic medium have been developed. The maximum absorbance of the extracted species for Cu and Mn compounds occurs at 480nm.Copper and manganese compounds react with the reagent in the molar ratio 1:1; 1:2;and 1:3 (metal:ligand) at pH 1.09 to 11 in a solution containing 20 % (v/v) of ethanol..A concentration of DMABR three times greater than the metal concentration was necessary for complete complexation; to give molar extinction coefficient (3.8 x 10³ at pH 2 and 7.6 x 10³ at pH 8) for Cu-DMABR.and (2.76 x10³ at pH 2 and 1.5 x 10³ at pH 8) for Mn-DMABR respectively. The interferences with some metal ions have been studied. The optimum experimental conditions were suggested for the determination of these metal ions.


KEY WORDS: 5(4-dimethylaminobenzylidene)rhodanine; copper, manganese ; spectrophotometric method


Global Jnl of Pure and Applied Sciences Vol.10(4) 2004: 577-583