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Abstract
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A series of pyrazole ligands named as 1,4-bis(3,5-dimethylpyrazol- 1-yl)butane (bbd), 1,3-bis(3,5-dimethylpyrazol-1-yl)propane (bdpp), and 1,3-bis(3,5-dimethylpyrazol-1-yl)propane-2-ol (bdpo) along with their transition metal complexes including [Cu2(m3-SCN)2 (m-bbd)]n, [Cu2(m3-SCN)2(m-bdpp)]n, and [Cu2Hg(m2-SCN)2(bdpo)2 (CH3COO)2]n were synthesized and characterized using FT-IR and Uv-vis spectroscopies, as well as thermal gravimetric analysis. The prepared compounds were investigated as corrosion inhibitors to protect mild steel in 0.5M H2SO4 solution. Corrosion tests were performed by electrochemical impedance spectroscopy and potentiodynamic polarization measurements. The pyrazole ligands exhibited inhibition efficiencies in a range of 38–78%, which intro- duced them as moderate inhibitors. On the other hand, the pyra- zole complexes showed inhibition efficiencies higher than 85%, demonstrating their high potentials to mitigate the steel corro- sion. In addition, the bimetallic complex resulted in higher corro- sion resistance than the two monometallic complexes. This was evidence of a critical role of the coordinated metal of the com- plex in forming an adhesive protection film on the steel surface.
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