Chitosan-based Unye bentonite-Pd nanoparticles: Highly active, reusable and efficient nanocatalyst for Sonogashira coupling reaction

Palladium (Pd) complexes supported on the polymers have been widely employed in various organic syntheses owing to their thermal stability, high catalytic activities, and recyclability [1]. Among different polymers, chitosan (CS) was found to have a high efficacy as a support due to biodegradability, biocompatibility, being non-toxic, positively charged, and availability [2]. These catalytic systems are found to be efficient towards different reactions such as coupling reactions including Sonogashira coupling reaction [3]. This work reports the preparation of Pd NPs onto a novel Schiff base modified chitosan-Unye bentonite (Pd NPs@CS-UN) catalyst which was characterized by FT-IR, EDS, XRD, HRTEM, Raman, elemental mapping, and XPS methods. Pd NPs@CS-UN was employed as an exceptional catalyst in Sonogashira coupling reactions between aryl halides (I, Br & Cl) and acetylenes in the presence of K2CO3 as base and EtOH as solvent. Regeneration of Pd NPs@CS-UN was carried out by filtration after the reaction completion.

Keywords:

Sonogashira coupling reaction , Biopolymer-supported Pd complex , Catalysis