Synthesis and characterization of azo sulfaguanidine complexes and their application for corrosion inhibition of silicate glass

Abstract

A new azo dye ligand of sulfaguanidine with 5‐nitro‐8‐hydroxyquinoline and its Mn(II), Ni(II), Co(II) and Cu(II) complexes were synthesized and characterized using elemental analysis, inductively coupled plasma, molar conductance, X‐ray powder diffraction, thermogravimetric analysis, magnetic moment measurements, and infrared, 1H NMR, electron impact mass and UV–visible spectral studies. The spectral studies and analytical data revealed that the azo dye ligand acts as a monobasic bidentate ligand via deprotonated OH and nitrogen atom of the azo group. The data support the mononuclear formulation of all complexes, except Cu(II) complex that has a binuclear formulation with a 1:2 metal to ligand ratio. The complexes have tetrahedral structure except Ni(II) which has octahedral geometry. The molar conductance data reveal that all the metal complexes are non‐electrolytic in nature The average particle size of the ligand and its Mn(II), Ni(II), Co(II) and Cu(II) complexes is 0.12–0.91 nm. The effect of these compounds for improvement of chemical durability of silicate glass in 0.1 M HCl was studied. Window and soda‐lime silica glass were taken as samples for the durability experiments. The inhibition efficiency of the ligand and its complexes for corrosion of glass surfaces after dissolution experiments was evaluated quantitatively using the specific weight loss method and qualitatively using scanning electron microscopy. The inhibition efficiencies of the tested compounds follow the order Co(II) complex > Mn(II) complex > Ni(II) complex > H3L > Cu(II) complex. The chemical durability improvement is 88.12–56.25% and 87.99–51.96% for window and soda‐lime silica glass, respectively. Copyright © 2016 John Wiley & Sons, Ltd.