Synthesis and
Characterization of New Azo dye and applications in colorimetric analysis of trace
metal ions in Aqueous Medium
Alsouz Mohammed A.K. and Al-jibouri Mahmoud Najim
Res. J. Chem. Environ; Vol. 27(5); 22-26;
doi: https://doi.org/10.25303/2705rjce022026; (2023)
Abstract
The chelation behavior of azo dye HL derived from coupling 4-nitrophenyl diazonium
salt with 7-hydroxycoumarin with Cd (II), Hg(II) and Fe (III) metal ions has been
studied. Reaction of the azo dye with Cd (II) and Hg(II) ions at different pH gave
new two complexes. At pH=8, complex of the formula [Cd(L)2]Cl2 was formed while
at pH=4.5, the complex [Cd(L) Cl2]. 2H2O was obtained. Another two new complexes
of the formula [Fe(L)2Cl2]Cl.2H2O have been obtained from the reaction of aqueous
solution of the azo dye with FeCl3.6H2O. All the above preparations were performed
after fixing the optimum pH and molar concentration. Wide range of molar concentrations
was investigated and the concentration which obeyed the Lambert-Beer’s Law, was
chosen.
The effects of time on the stability of these complexes were checked. The stoichiometry
of the above prepared complexes was determined using mole ratio and Job methods.
A great bathochromic shift was observed in the UV–Vis absorption spectra of (10-6-10-8
mole/lit.) of an aqueous solution of the solid complexes. The vibration spectra
of these complexes gave different changes compared to that of the free ligand. The
1H NMR spectra for one of the complexes were also performed.
