Green synthesis of palladium nanoparticles and their catalytitc performance in acyl free copper sonogashira coupling

The green synthesis of metal nanoparticles (MNPs) has made a broad spectral progress in recent times due to their novel electronic, chemical, catalytic, magnetic and optical properties.1 The Sonogashira coupling reaction of terminal alkynes with acyl halides provides a powerful and versatile method for preparing ynones, which has been widely applied to multicomponent syntheses of heterocycles.2 In this research, we investigated a one-step green method to generate nanoparticles of palladium (PdNPs) from palladium chloride (PdCl2) by using polyphenolic compound: Tannic acid as a reducing and stabilizing agent. PdNPs were characterized by ICP-AES elemental analysis, UV-visible, XRD, EDX and SEM analaysis. The synthesized PdNPs@tannic acid was used as nanocatalyst in ligand and copper free Sonogashira coupling reaction under aerobic condition in order to multicomponent synthesis of heterocycles via ynones as intermediate. Typically, the coupling of benzoyl chloride 1 and phenylacetylene 2 in the presence of PdNPs@tannic acid gives 1,3-diphenylprop-2-yn-1-one 3 and followed by the reaction of 3 with 3-chloro phenylhydrazine hydrochloride 4 under basic condition produced 1-(2-chlorophenyl)-3,5-diphenyl-1H-pyrazole 5 (Figure 1). The structure of product was confirmed by 1H NMR and FT-IR spectroscopy.

کلیدواژه ها:

Green synthesis ، Palladium nanoparticles ، Tannic acid ، Sonogashira coupling reaction ، Multicomponent reaction