Synthesis, structural characterization, and corrosion inhibition properties of rare earth 2-hydroxyphenylacetate coordination polymers
Journal Publication ResearchOnline@JCUAbstract
The salt metathesis reaction between sodium 2-hydroxyphenylacetate (Na(2hpa)) and a rare earth (RE) metal nitrate or chloride in an aqueous ethanol medium has yielded a series of rare earth one-dimensional (1-D) coordination polymers [La(2hpa)3(H2O)2]n (1), {[RE2(2hpa)6(H2O)4]⋅3.5H2O}n (RE = Ce (2), Nd (3)), and {[RE2(2hpa)6(H2O)2]·3H2O}n (RE = Gd (4), Dy (5), Y (6), Er (7), Yb (8)) which have three different crystal structures. All structures were determined by single-crystal X-ray diffraction (XRD), except Y (6) and Yb (8) compounds, which were isomorphous with Gd (4), Dy (5), and Er (7) complexes by their unit cell parameters and X-ray powder diffraction (XRPD) patterns. Only the La complex (1) has a mononuclear repeating unit while the others are based on binuclear units. The chelating bridging carboxylate coordination mode is common for all complexes. In addition, complexes 1–3 exhibit the chelating mode with the 10-coordination number whereas complexes 4–8 have syn-syn-bridging bidentate binding with the coordination number of 9. In the weight loss anti-corrosion experiments, the {[Gd2(2hpa)6(H2O)2]·3H2O}n (4) compound demonstrated the highest inhibition efficiency of 57 %. A significant difference between RE 2-hydroxyphenylacetate complexes and [Ce(salH)3(H2O)]n was usually not observed indicating little impact of the -CH2- unit between carboxylate and benzene ring. The reduced corrosion inhibition efficiencies of RE 2-hydroxyphenylacetate complexes compared with RE 4-hydroxyphenylacetates confirm the positive effect of the p-OH group on the benzene ring on anti-corrosion properties. Graphical abstract
Journal
Inorganica Chimica Acta
Publication Name
Inorganica Chimica Acta
Volume
587
ISBN/ISSN
1873-3255
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Pages Count
10
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Elsevier
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DOI
10.1016/j.ica.2025.122796