Synthesis and characterization of nano-cellulose immobilized phenanthroline-copper (I) complex as a recyclable and efficient catalyst for preparation of diaryl ethers, N-aryl amides and N-aryl heterocycles

Functionalized nanocellulose was prepared and employed for immobilization of phenanthroline-copper(I) complex to afford cellulose nanofibril grafted heterogeneous copper catalyst [CNF-phen-Cu(I)]. This nano-catalyst was well characterized using FT-IR, NMR, XRD, CHNS, AAS, TGA, EDX and SEM. The activities of the synthesized catalyst were examined in the synthesis of diaryl ethers via C-O cross-coupling of phenols and aryl iodides, as well as, the preparation of N-aryl amides and N-aryl heterocycles through C-N cross-coupling of amides and N-H heterocycle compounds with aryl halides. In this trend, various substrates containing electron-donating and electron-withdrawing groups were exploited to evaluate the generality of this catalytic protocol. Accordingly, the catalyst demonstrated remarkable catalytic efficiency for both C-N and C-O cross-coupling reactions, thereby resulting in good to excellent yields of the desired products. Furthermore, the recover-ability experiments of the catalyst showed that it can be readily retrieved by simple filtration and successfully reused several times with negligible loss of its catalytic activity.