Synthesis and Catalytic Performance of Fe ₃ O ₄ @L-Arginine/La ₂ O ₃ Magnetic Nanoclusters in Pechmann Condensation

Coumarin derivatives represent an important class of heterocyclic compounds with broad applications in pharmaceuticals, agrochemicals, and functional materials. Consequently, there is ongoing interest in developing efficient and eco-friendly catalytic systems for their synthesis. In this study, a new heterogeneous magnetic nanocatalyst (Fe3O4@L-Arginine/La2O3 magnetic nanoclusters) was prepared via a simple co-precipitation method using FeCl2.4H2O, FeCl3.6H2O, L-Arginine, and La(NO3)3.6H2O in the presence of NaOH under a nitrogen atmosphere. The prepared compound was characterized by FT-IR, XRD, Raman, TEM, FE-SEM, EDX, TGA, VSM, and ICP-AES analyses. Fe3O4@L-Arginine/La2O3 magnetic nanoclusters exhibited good catalytic activity and were found to condense via the Pechmann reaction to form coumarin derivatives with high yields in short reaction times at mild conditions, using ethanol as a green solvent and a low catalyst concentration (5 mol%). This system has obvious benefits, which are compared to earlier reported catalysts, as highlighted in the fact that there is simplicity in magnetic recovery, good structural integrity, negligible metal leaching, and high recyclability with a low loss of activity. The synergistic effect of the active sites of the La2O3 acid with the multifunctional L-Arginine surface groups is considered to be the reason for the high catalytic efficiency of the reaction substrates. In general, this publication presents a strong, eco-friendly, and reusable magnetic nanocatalyst that has a tremendous value in reusable coumarin synthesis.