Quinoxalines as analytical reagents : Derivatives containing the copper (I)-specific grouping

Abstract

2,3-Bis(2-pyridyl)quinoxaline and 25 substituted derivatives were prepared and assessed as spectrophotometric reagents for copper The compounds contain the copper(I)-specific “cuproine” grouping, but are much more readily prepared than most cuproine-type reagents The possible formulations of the copper(I) chelates present under various conditions, and the effect of substituents are discussed 2,3-Bis[2-(6-methyl)pyridyl]quinoxaline showed the greatest sensitivity for copper and was evaluated quantitatively with respect to ligand : copper ratio, pH effects, interfering ions and Beer's law dependence