Synergistic effect of antiferromagnetic hematite on cuprous oxide nanocomposite: enhanced catalytic activity and reusability for N-arylation of imidazole

The synergistic effect of the antiferromagnetic hematite on copper oxide (Fe 2 O 3 –Cu 2 O) was synthesized successfully by the co-precipitation method in an aqueous medium, and the loading process was carried out using the ultrasonication method to obtain a nanocomposite. The prepared nanocomposite was used as a heterogeneous catalyst for N-arylation of the imidazole, the pharmaceutically important reaction. The nature of the catalysts such as morphology, crystal properties, surface area, chemical nature, and magnetic properties were studied using SEM, FE-SEM, XRD, FT-IR, BET surface area, VSM, etc. The XPS analysis reveals that the prepared composite contains Fe 3+ and Cu + oxidation states and the strong interactions between Fe(III) and Cu(I) which binds those species together during catalytic reaction and improves the reusability. To evidence this, the Fe 2 O 3 -Cu 2 O (75%:25%) was reused for five consecutive cycles without much significant loss in the catalytic activity. However, the physical mixtures of bare Fe 2 O 3 and bare Cu 2 O give comparatively lesser yield than the Fe 2 O 3 -Cu 2 O composite. Therefore, the Fe 2 O 3 –Cu 2 O (75%:25%) is an efficient, easy-to-use, and environmentally begin catalyst for N-arylation reactions. Graphical abstract