Palladium Nanoparticles Doped Phenanthroline-Based Covalent Organic Framework for Suzuki-Miyaura Cross-Coupling Reactions

Abstract

The challenges associated with the Suzuki-Miyaura reaction using costly, less sustainable homogeneous catalysts increased the surge to develop highly efficient, cost-effective, and sustainable heterogeneous catalysts. This work explains the strategy and synthesis of phenanthroline-based covalent organic framework (PhenCOF), which serves as a support matrix, followed by its reduction with palladium salt to form PdNPs@PhenCOF to prevent the leaching of the metal. The formation of PhenCOF and Pd nanoparticles (NPs) decorated PdNPs@PhenCOF was well characterised using TGA, FT-IR, FE-SEM, HRTEM, EDS, XPS, PXRD, and N 2 adsorption-desorption techniques. The ICP-OES analysis reveals the Pd loading of 3.4 wt%, and HRTEM reveals the average nanoparticle size of 1 nm in PdNPs@PhenCOF.The developed green catalyst exhibits efficient catalytic activity in Suzuki-Miyaura carboncarbon (C-C) bond formation under mild, environmentally benign conditions. The catalytic approach demonstrates the potential of PdNPs@PhenCOF for a broad substrate scope, achieving higher product yields. The findings underscore the stability and reproducibility of PdNPs@PhenCOF, which exhibit an exceptional turnover number (TON) of 1256 while maintaining excellent recyclability over 7 consecutive cycles, with minimal loss in TON. The results further highlight the applicability of PdNPs@PhenCOF as a sustainable alternative for crucial synthetic bond formations via a heterocatalytic approach. Thus, this approach contributes to the development of greener methodologies towards C-C bond formation with broad applicability, exceptional functional-group tolerance, and scalability by using a support matrix that requires minimal usage of metal, thereby increasing its practicality to form a C-C bond at room temperature.