Nanomagnetic picolylamine- based complex of palladium as an efficient heterogeneous catalyst for selective reduction of nitroarenes in water

In this study, a novel heterogeneous palladium complex stabilized on Fe₃O₄ magnetic nanoparticles (MNPs) was synthesized via a three-step procedure involving the functionalization of iron oxide surface with an electrophilic group (C-Cl), subsequent nucleophilic substitution reaction with 2-picolylamine, and final complexation with palladium chloride. The catalytic performance of the resulting magnetic heterostructure was then evaluated in the selective hydrogenation of nitroarenes and N-heteroarenes using NaBH₄ as a reducing agent. The reactions proceeded efficiently under mild, green conditions specifically, in water at room temperature to delivering the desired aniline derivatives in good to excellent yields (81-98%) within short reaction times (25-90 min). While electronic and steric factors influenced the reaction outcome, this system consistently outperformed previously reported methods in terms of both yield and reaction speed. Moreover, the catalyst exhibited exceptional stability and reusability, maintaining its structural integrity and high catalytic activity over five successive cycles without significant degradation.