Efficient and green: biowaste-derived N-rich carbon for palladium-catalyzed CO gas-free carbonylative annulation with DFT insights

Abstract

This study presents a catalytic approach utilizing nitrogen-rich carbon (NRC-FS-4) derived from fish scales, a biowaste material, as a sustainable and robust support for palladium nanoparticles (PdNPs). The resulting nanocatalyst (PdNPs@NRC-FS-4) demonstrates high efficiency in the ligand and carbon monoxide (CO) gas-free carbonylative annulation of aryl halides, enabling the synthesis of quinazolinones and benzimidazoles. Transforming fish scales into a nitrogen-enriched carbon source valorizes waste and enhances PdNP catalytic activity and stability. Comprehensive characterization techniques reveal the structural and compositional features of PdNPs@NRC-FS-4, underpinning its superior catalytic performance. The process employs a green CO surrogate and delivers high selectivity under mild conditions. The catalyst retains its activity over five successive cycles, highlighting its recyclability and economic viability. Density functional theory (DFT) computations provide insights into the catalytic cycle, reinforcing the mechanistic understanding of the amino-carbonylation reaction. This work underscores the potential of biowaste-derived materials in fostering resource-efficient and eco-friendly catalytic processes for synthesizing pharmacologically relevant compounds.