Controlled Ni-doped cobalt ferrite nanoparticles: a green and sustainable heterogeneous catalyst for the synthesis of 5-substituted 1H-tetrazoles via a [3+2] cycloaddition reaction

Abstract

This study explores the catalytic potential of sustainable Ni_xCo_1−xFe₂O₄ (x = 0.0, 0.4, 0.6, 1.0) nanoparticles for the efficient synthesis of bioactive 5-substituted-1H-tetrazoles. The impact of Ni substitution on cobalt ferrite samples was investigated via analytical techniques such as SEM, PXRD, HRTEM, EDX, IR, and VSM. XRD analysis results confirmed the synthesis of ferromagnetic cubic nanostructured material. Furthermore, the formation of a well-defined cubic spinel-structured nanomaterial with an average size of 15.73 nm was revealed by the SEM and TEM micrographs. Tetrazoles represent a vital class of heterocyclic scaffolds with diverse applications in high-energy material science, medical chemistry, biochemistry, and pharmacology, among other domains. Leveraging their importance, we developed a high-yielding facile protocol for tetrazole synthesis via a [3+2] cycloaddition reaction between sodium azide and aromatic nitriles catalyzed by Ni_xCo_1−xFe₂O₄ (x = 0.4) under optimized reaction conditions. The catalytic protocol demonstrated exceptional efficiency, achieving up to 93% isolated yield with broad functional group tolerance, surpassing various existing catalytic systems. The key advantage of this synthetic protocol is the magnetic nature of the catalyst, which allows for easy separation and superior recyclability with insignificant activity loss, which are in accordance with green chemistry principles. This catalytic system is a prospective substitute for medicinal and industrial applications because of its high catalytic efficiency, reusability, and sustainability. This study demonstrates biogenic nickel-doped cobalt ferrite nanoparticles as economical, environmentally benign catalysts for tetrazole scaffold synthesis, providing a scalable and sustainable method of producing bioactive compounds.