Copper(II) Oxide Nanoparticles Impregnated on Melamine-Modified UiO-66-NH2 Metal-Organic Framework for C-N Cross-Coupling Reaction and Synthesis of 2-Substituted Benzimidazoles

A zirconium-based metal-organic framework, UiO-66-NH2, modified by melamine (Mlm) was used as a support for CuO nanoparticles (NPs). Melamine offered a platform for uniform and homogeneous distribution of NPs on the surface of the frameworks and made a strong bonding to the NPs to avoid undesirable leaching. UiO-66-NH2-Mlm/CuO NPs were used for the Buchwald-Hartwig C-N cross-coupling reaction to synthesize arylated anilines from phenyl iodide, bromide, and chloride and primary and secondary amines in DMF at 110 degrees C. The catalyst was also employed for the synthesis of 2-substituted benzimidazole derivatives from various aromatic aldehydes and o-phenylenediamine in the absence of an oxidant in EtOH at room temperature. The catalyst was recyclable and reusable for several times and exhibited good stability (examined by BET, XRD, and SEM-EDX) in reaction conditions.