Synthesis of magnetically separable copper nanocatalyst and their application as an efficient catalyst for C(sp2)–C(sp) and C(sp2)–C(sp2) cross-coupling reactions

A copper complex was immobilized on Schiff base modified magnetic Fe3O4@SiO2 nanoparticles by covalent linkage. The obtained nanoparticles were identified with various characterization methods. The nanocatalyst shows good activity toward Sonogashira and Suzuki cross-coupling reaction in environmentally friendly solvent (H2O/DMF) under mild conditions. The catalyst shows not only high catalytic activity, but also offers many practical advantages such recyclability and air stability. Expectedly, the nanocatalyst can be applied in large-scale industrial synthesis. The SEM micrographs of the products Fe3O4 and nanocatalyst are given in Fig. 1(a) and Fig. 1(b) respectively. It was found that the nanoparticles were present as uniform particles with spherical morphology. SEM images reveal that Fe3O4 particles are aggregated particles having rough external surfaces (Fig. 1(a)). Silica coating makes the particles exhibit smooth and spongy surfaces (Fig. 1(b)) which indicatives the successful coating of silica over the magnetic nanoparticles. However, the nanocatalyst particles still fall in the nano-size range