Highly Active Pandanus Nanocellulose-Supported Poly(amidoxime) Copper (II) Complex for Ullmann Cross-Coupling Reaction

The transition metal-catalyzed chemical transformation of organic electrophiles, and organometallic reagents have turned up as an exceedingly robust synthetic tool. The evolution of transition metal catalysts has attained a stage of civilization that authorizes for an extensive scope of chemical bonds formation partners to be combined efficiently. The applications of Cu-based nanoparticles have received great attention owing to the earth-abundant, low toxicity and inexpensive. Due to these characteristics, copper nanoparticles have generated a great deal of interest especially in the field of catalysis. In this study, bio-waste pandanus fiber nanocellulose-graft-poly(acrylonitrile) was synthesized by undergoes free-radical initiation process and followed by Beckmann-type rearrangement with hydroxylamine under alkaline conditions converted into the poly(amidoxime) ligand and anchored the copper onto poly(amidoxime) functionalized pandanus nanocellulose. Biocatalyst; CuNPs@ PAM was characterized using different techniques such as FTIR, FE-SEM, EDX, TEM, TGA, DSC, ICP-OES, XRD and XPS analyses. The CuNPs@ PAM showed high stability and high catalytic activity in a wide variety of electrophilic substituted phenols with substituted aryl/benzyl halides. 0.03 mol%, ±3 mg of CuNPs@ PAM could efficiently promoted Ullmann reaction to give the corresponding coupling product in up to 99 % yields. The complex was easy separated and recover from the reaction mixture by simple filtration. Leaching studies performed by hot filtration experiments show that the synthesize copper catalyst are stable under the reaction conditions