Fe3O4@SiO2@(CH2)3-urea-thiourea as a new hydrogen-bonding and retrievable nanomagnetic catalyst was fabricated and its structure confirmed by transmission electron microscopy (TEM), thermogravimetric analysis/ derivative thermogravimetric (TGA/DTG), vibrating sample magnetometer (VSM), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and elemental mapping analysis. The catalytic performance of the novel hydrogen-bonding catalyst was appropriately probed through the multicomponent preparation of bipyridine-5-carbonitriles via a cooperative vinylogous anomeric based oxidation (CVABO) mechanism in the absence of any solvent. The novel hydrogenbonding nanomagnetic catalyst can readily be regained and reused four times without appreciable destruction of catalytic efficiency.
