Fabrication of novel and promising heterogeneous nanocatalyst Fe2O3-g-C3N4/Cu(II) derived from MIL-53(Fe) and decorated with copper as an efficient and reusable catalyst for Hantzsch reaction

Copper-containing Fe2O3 with g-C3N4 framework (Fe2O3-g-C3N4/Cu(II)) composite is fabricated and its characterization was followed by various analyses. Firstly, the compound MIL-53(Fe) was constructed and utilized as a precursor to generate Fe2O3. Fe2O3-g-C3N4 was prepared by pyrolysis of MIL-53(Fe) material in the presence of urea and KBr at 550 °C and then treated with Cu(NO3)2.3H2O to produce Fe2O3-g-C3N4/Cu(II) composite. The constructed hybrid nanomaterial was applied as a nanocatalyst in the formation of polyhydroquinoline derivatives via Hantzsch reaction with excellent yields between 91 and 97% in the absence of solvent at 75 °C (10 mg catalyst loading within 20–35 min). Owing to the synergistic effect of basic sites (C3N4) and acidic sites (Cu), Fe2O3-g-C3N4/Cu(II) displayed exceptional catalytic activity. Moreover, Fe2O3-g-C3N4/Cu(II) has exhibited recyclability for six runs.