Synergistic promotion of Ag nanoparticles supported on magnetic Cu based metal organic framework for A3-coupling and synthesis of benzopyranopyrimidines

Abstract

Enhancing the stability of metal nanoparticles is of great interest in the field of heterogeneous catalysis. An attractive prospect to this is the incorporation of metal nanoparticles into metal organic frameworks (MOFs) as it not only enhances the stability of metal nanoparticles but also influences their activity and selectivity. In the present study, we have prepared two magnetic silver catalysts (Ag@CuBTC–Fe₃O₄–PDA and Ag@Fe₃O₄–PDA) using two different supports to explore the effect of CuBTC on the catalytic activity of Ag nanoparticles. The catalytic activity of both catalysts was studied for the A³-coupling reaction and synthesis of benzopyranopyrimidines, wherein Ag@CuBTC–Fe₃O₄–PDA showed unexpectedly excellent catalytic performance. This excellent catalytic activity was attributed to the high surface area and nano-confinement effect provided by CuBTC which helps in the proper dispersion of silver nanoparticles and also helps in preventing their aggregation. Moreover, synergistic interaction between CuBTC and Ag nanoparticles in Ag@CuBTC–Fe₃O₄–PDA also plays an important role in the enhancement of the catalytic activity of Ag nanoparticles in comparison to Ag@Fe₃O₄–PDA. Furthermore, FT-IR, XRD, ICP-AES and XPS analysis of reused catalyst showed that the catalyst retains its structure, and chemical environment and can be reused up to six times.