Polyvinyl alcohol-stabilized cuprous oxide particles: efficient and recyclable heterogeneous catalyst for azide–alkyne cycloaddition in water at room temperature

Abstract

The PVA-stabilized Cu2O particles were prepared using a novel and simple rout in aqueous medium at room temperature under aerobic conditions. Initially, Cu(II) ions were fixed in PVA matrix via complex formation with OH groups, subsequently this PVA–Cu(II) macromolecular complex as a precursor reacted with ascorbic acid as a reducing agent at pH = 12 to obtain the PVA–Cu2O composite. The products were characterized using XRD, FE-SEM, FTIR, and UV–Visible techniques. The as-prepared PVA–Cu2O composite was applied as an effective and recyclable heterogeneous catalyst for 1,3-dipolar cycloaddition reactions between terminal alkynes and azides to prepare 1,2,3-triazoles under an environmentally friendly reaction conditions. The substituted triazoles were produced of various aryl and benzyl azides using a catalytic amount of this composite as efficient, stable, and air- and moisture-tolerant catalyst in excellent yields in water at room temperature. These PVA-stabilized Cu2O particles could be recovered in a facile manner from the reaction mixture and reused several times without any loss of catalytic activity.