Rare Earth 2‐Methyl‐3‐furoate Complexes: Effect of Steric Hindrance on Corrosion Inhibitor Properties

Abstract

AbstractThe preparation and characterization of six rare earth 2‐methyl‐3‐furoate (2m3fur) complexes are detailed in this study. Analysis through single‐crystal X‐ray diffraction, as well as powder XRD, reveals that all six compounds belong to one of two structural groups: {[RE2(2m3fur)6(EtOH)] ⋅ H2O}n (RE=La, Ce, Pr) and [RE3(2m3fur)9]n (RE=Y, Er, Yb). These structural groups feature carboxylate coordinated linear polymers. The former complexes have two distinct metal centers, one ten coordinate and one nine, with lattice water participating in a hydrogen bond with coordinated ethanol. The latter structures, involving erbium, ytterbium, and yttrium, have three unique metal centers: two eight coordinate, and one seven‐coordinated. In corrosion inhibition tests on mild steel in 0.01 M NaCl solution, the maximum efficiency was observed with [Y3(2m3fur)9]n at 59 %, which is less effective than yttrium 3‐furoate (90 % efficiency). The results suggest that the steric effect of the methyl group adversely affects corrosion inhibition.