Natural Amino Acid-Derived Iron(III) Catalysts for Green Oxidation Chemistry Applications

Iron-complex peroxide activators make up a group of catalysts developed to perform green oxidation chemistries. They are among the most efficient, environmentally friendly oxidants, but several structural challenges limit their wider applications. In this study, we altered the traditional synthesis of these iron complexes by using natural amino acids, thereby increasing the hydrolytic stability and planarity of the iron-complex structures, which improved their reactivity. Three different iron complexes were synthesized (1-A, 1-B, and 1-C) and characterized through multiple techniques, including Electrospray Ionization-Mass Spectrometry (ESI-MS). 1-C was used for dye degradation studies, demonstrating its ability to remove ∼98% of synthetic dyes from water within 20 min under optimized conditions. The degradation followed an overall second-order kinetics with an apparent rate constant (<i>k</i> _app = 8.5 × 10⁵ M^-1 min^-1) consistent with values reported in previous Fe-TAML/H₂O₂ studies. Total Organic Carbon (TOC) analysis in the byproduct indicated a 30% mineralization by the end of the degradation with the remaining 70% converted to products identified by Compact Mass Spectrometry (CMS) analysis. The rapid oxidative degradation of dyes by 1-C was attributed to the formation of high-valent iron-oxo species, as supported by UV-vis and CMS analyses.