Pr6O11/Fe2O3 Bimetallic Nanocatalyst: An Efficient and Reusable System for Ultrasound-Assisted Tetrazole Synthesis in an Aqueous Medium with a Molecular Docking Study and Anticancer Evaluation.

The development of green, efficient, and recyclable heterogeneous catalysts for the synthesis of biologically important tetrazole derivatives under environmentally benign conditions remains a significant challenge. In this study, a bioassisted Pr6O11/Fe2O3 bimetallic nanocatalyst was successfully synthesized via a simple coprecipitation method using Moringa oleifera gum extract as a natural stabilizing agent. The synthesized nanocatalyst was comprehensively characterized, confirming the successful formation of a highly crystalline, mesoporous, and magnetically recoverable material with excellent physicochemical properties. The catalytic performance of the Pr6O11/Fe2O3 nanocatalyst was evaluated for the ultrasound-assisted one-pot synthesis of 5-substituted 1H-tetrazole derivatives in an aqueous medium. The developed protocol afforded the desired products in excellent yields (89-96%) under mild reaction conditions and demonstrated excellent recyclability, maintaining high catalytic activity over five consecutive reaction cycles with an only marginal decrease in yield. The green-synthesized Pr6O11/Fe2O3 bimetallic nanocatalyst also exhibited moderate anticancer activity against MCF-7 breast cancer cells with an IC50 value of 93.59 μg mL-1. In addition, molecular docking studies of the synthesized tetrazole derivatives against the EGFR kinase domain (PDB entry 1XKK) revealed favorable binding interactions, with 5-(3,4-dichlorophenyl)-1H-tetrazole showing the highest binding affinity (-19.20 kcal mol-1), comparable to that of reference drug erlotinib (-19.94 kcal mol-1). Overall, this study presents a sustainable and reusable catalytic platform that integrates green nanocatalyst synthesis, efficient tetrazole production, and preliminary biological evaluation, providing a promising approach for the development of environmentally benign catalytic systems with potential medicinal relevance.