EDTA-Co(ii) complex functionalized magnetic nanoparticles: as a heterogeneous catalyst for the synthesis of 5-substituted 1H-tetrazoles

In this study, we report the synthesis of an EDTA coordinated cobalt complex [EDTA-Co(II)] immobilized on the surface of Fe₃O₄ magnetic nanoparticles (MNPs) via a three-step post-synthetic modification approach. The structure of the prepared catalytic nanocomposite was comprehensively characterized using a suite of spectroscopic, physical, morphological, and elemental analytical techniques. The catalytic efficiency of this nanocomposite was evaluated in the synthesis of 5-substituted 1H-tetrazoles via the [3 + 2] cycloaddition of sodium azide to nitriles at 120 °C in polyethylene glycol 400 (PEG-400) as a green solvent. This approach yielded the desired products with excellent yields and selectivity in short reaction times. Hot filtration, leaching and reusability studies confirmed the catalyst's high stability and recyclability with negligible loss of activity.