A facile one-step approach for the synthesis of uniform spherical Cu/Cu2O nano- and microparticles with high catalytic activity in the Buchwald-Hartwig amination reaction

In the present work, we have developed a rapid, one step, calcination-free protocol for the synthesis of uniform spherical Cu/Cu2O nano/microparticles (NMPs). The synthesis of Cu/Cu2O NMPs was achieved by microwave irradiation of copper acetate as a precursor and 1,4-butanediol as a solvent in a few minutes. The prepared Cu/Cu2O NMPs gave 100% yield of uniform spherical morphology. 1,4-Butanediol plays a crucial role in reactions such as a solvent, reactant, stabilizer and capping agent which control the crystal morphology. The resultant product was characterized with the help of different techniques such as XRD, FEG-SEM, EDS, TEM, FT-IR, TPR, DSC-TGA, XPS and BET surface area analysis. The results confirm that the Cu/Cu2O NMPs had good crystallinity and were essentially pure. This is a simple, faster, inexpensive and additive-free protocol for synthesis of nanocrystalline Cu/Cu2O compared to the conventional method. These Cu/Cu2O NMPs showed excellent catalytic activity in the Buchwald-Hartwig amination coupling reaction. Notably the reaction does not require any ligand source, and requires low catalyst loading, and low temperature with catalyst recyclability.