Spectrophotometric determination of the stoichiometry of cobalt (II)‎ and copper (II)‎ salicylhydroxamate complexes

Abstract EN

Salicylhydroxamic acid was prepared by coupling reaction of methyl salicylate and free hydroxylamine, precipitated by acidification and recrystallized by hot water/ acetic acid it was characterizedby melting point, iron and vanadiumcolor test and FT-IR absorption bands at 3260cm-1 (OH), 1663 cm-1 (C=O), and 900 cm-1 (N-O) and 1H-NMR characteristic peak of the proton of the hydroxyl group attached to the nitrogen atom in the region 9.566 – 9.762 ppm.

the shifting of the resonance signal of hydroxyl proton to lower field supports intermolecular hydrogen bonding.

the peak proton of aromatic ring appears in the region 7.699 – 7.714 ppm.

the peakprotons of – NH appears in the region 3.772 – 3.783 ppm.The 13C NMR spectra exhibit absorption signal due to carbonyl (C=O) group at nearly 166.118 ppm.

the chemical shifts of aromatic carbons appear in the region of 133.329 – 127.148 ppm.

the complexation ofsalicylhydroxamic acideither withCo2+ orCu2+cation wasboth determined by continuous variationmethod.

Spectrophotometric analysis for determination of Co2+ and Cu2+salicylhydroxamate complexes was based on formation of colored complexes in weak acidic media.

the produced colored complexes of Co2+ andCu2+showed maximum absorption at λmax510 nmand 385nm respectively.

The mole ratio of complexes were determined in different chemical environments,and found to be in ratio of 1:3 and 1:1( M:L), respectively.