Copper supported on MWCNT-guanidine acetic acid@Fe3O4: synthesis, characterization and application as a novel multi-task nanocatalyst for preparation of triazoles and bis(indolyl)methanes in water

Abstract

The synthesis of a new supported copper (Cu) nanocatalyst, with highly dispersed particles, based on magnetic guanidine acetic acid (GAA) functionalized multi-wall carbon nanotubes (MWCNT), Cu/MWCNT-GAA@Fe₃O₄, is reported. The synthesized nanocatalyst was characterized by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray, elemental analysis (carbon, hydrogen, nitrogen), thermogravimetric analysis and Fourier transform-infrared. The catalytic activity of Cu/MWCNT-GAA@Fe₃O₄ was investigated in 1,3-dipolar cycloaddition and condensation reactions in water. The results showed a wide range of 1,2,3-triazoles and bis(indolyl)methanes were synthesized with good to excellent yields in a short time. The nanocatalyst could be recovered by applying an external magnetic field, which resulted in easy separation of the catalyst without filtration and this could be reused for several runs without loss of significant activity.