Solvent extraction and spectrophotometric determination of palladium(II) with some nitrogen-containing heterocyclic hydrazones in the presence of chloride ions

Three terdentate hydrazones, all containing the 1-phthalazino grouping in the hydrazine moiety but differing in the heterocyclic substituent in the aldehyde moiety, have been used as analytical reagents for palladium(II), the optimal conditions for the extractive spectrophotometric determination of palladium(II) in the presence of chloride ions being deduced. These compounds are highly selective and sensitive reagents for palladium(II), since they are not extracted into chloroform from sulfuric acid solutions and do not react with other platinum group metals. The desirable spectral properties of the palladium(II) complex of benzothiazole-2-aldehyde-1-phthalazinohydrazone (BAPhH) have also been discussed with respect to preference of the C  N structural form in the heterocyclic ring on the aldehyde moiety of the ligand.