Magnetically separable iron oxide nanoparticle for reduction of nitroarenes and reductive amination of carbonyl compounds in aqueous medium

Novel biogenic iron oxide nanoparticles (Fe@BNPs) were synthesised using Adiantum capillus-veneris extract (aq.) as a capping and stabilising agent and meticulously characterized using FT-IR, UV–vis, FESEM, EDX, TEM, XPS, and XRD techniques. Subsequently, Fe@BNPs were employed for the catalytic reduction of various nitroaromatic compounds employing hydrazine hydrate under benign reaction conditions in water. Notably, the magnetic behaviour of Fe@BNPs enabled their facile recovery using an external magnet, facilitating catalyst reuse in multiple cycles with minimal leaching or loss of activity. Furthermore, the versatility of Fe@BNPs was demonstrated through their application in reductive amination reactions, employing nitro-reduced primary amines and carbonyl compounds. This ligand-free approach offers significant advantages including environmental sustainability, green solvent, exceptional product yields, straightforward workup procedures, efficient purification, gram-scale reactions and excellent catalyst reusability.