A Palladium Nanocatalyst Enabling Green Heteroaryl Suzuki Cross-Coupling and Anticancer Activity with Photophysical and TD-DFT Insights of Biaryl Products

Abstract

A sustainable nanocatalytic system is developed for efficient heteroaryl cross-coupling and biological applications. Palladium nanoparticles (PdNPs) supported on sodium montmorillonite (Na-MMT) are synthesized through an environmentally benign route, affording a uniformly dispersed and stable nanocatalyst (APM-PdNPs@Na-MMT). Structural and surface analyses confirm the successful immobilization of PdNPs on the clay support. The nanocatalyst efficiently promotes Suzuki cross-coupling reactions of N-heterocyclic bromides and chlorides in green solvents under mild conditions, delivering biaryl products in high yields with broad functional group tolerance. Excellent scalability is demonstrated through gram-scale reactions without loss of catalytic efficiency. Recyclability and leaching studies reveal high stability, sustained activity, and true heterogeneous behavior. The photophysical properties of the synthesized molecules are investigated using ultraviolet-visible (UV-Vis) and fluorescence spectroscopy, supported by time-dependent density functional theory (TD-DFT) calculations. Notably, the nanocatalyst exhibits selective anticancer activity against HCT116 colon cancer cells while showing minimal cytotoxicity toward normal human embryonic kidney (HEK) cells. This work underscores the potential of clay-supported palladium nanocatalysts in sustainable catalysis and biomedical applications.