In this thesis, Co0.5Zn0.5Fe2O4 magnetic nanoparticles were prepared through a green synthesis route using tragacanth gum and employed as a heterogeneous catalyst for the synthesis of polyhydroquinoline derivatives. The magnetic nanoparticles were characterized by XRD, FESEM, TEM, EDX, elemental mapping, BET, and VSM analyses. XRD confirmed the formation of a cubic spinel structure with an average crystallite size of about 20 nm, and TEM showed mainly spherical particles with sizes of 30-40 nm. The BET surface area was 29.505 m2 g-1, and the nanoparticles exhibited a mesoporous structure. VSM analysis showed soft ferromagnetic behavior with a saturation magnetization of 27.93 emu g⁻¹. The catalytic activity of the nanoparticles was evaluated in the four-component synthesis of polyhydroquinoline derivatives under solvent-free microwave irradiation. The optimized conditions were 0.02 g of catalyst and 360 W microwave power, giving the model product in 95% yield within 10 min. Different aromatic aldehydes afforded the corresponding products in 87-97% yields within 9-13 min. The catalyst was magnetically recovered and reused over four runs with only a slight decrease in catalytic activity. These results demonstrate the efficiency and practical applicability of Co0.5Zn0.5Fe2O4 nanoparticles for solvent-free microwave-assisted polyhydroquinoline synthesis.
