Immobilization of Copper Nanoparticles onto Activated Multi-Walled Carbon Nanotubes and a Study of its Catalytic Activity as an Efficient Heterogeneous Catalyst for a Three Component Synthesis of Triazoles from In Situ Generated Azides

An efficient, regioselective, one pot and two-step synthesis of -hydroxy 1,4-disubstituted 1,2,3-triazoles from a wide range of nonactivated terminal alkynes and epoxides and sodium azide by way of a three-component “click reaction” using a catalytic amount of (meso-tetrakis(o-chlorophenyl)porphyrinato)copper(II) (5 mol-%) in excellent isolated yields is described. By performing two reaction steps in one pot and purifying only at the final step, this procedure excludes any interim purification of in situ generated organic azide intermediates, which significantly improves the overall yield and reduces the reaction time.Leaching experiments after ten successive cycles showed that the catalyst is most strongly anchored to the AMWCNT support. Mechanistically porphyrinatocopper catalyzes each step of reaction in different ways as a bifunctional catalyst including epoxide ring opening by azide delivery to epoxide, forming in situ generated 2-azidoalcohols followed by activation of the C-C triple bond of the starting terminal alkynes by forming a porphyrinatocopper-acetylide intermediate and thereby promotes the [3+2]-cycloaddition reaction as the key step to form the triazole framework.

Keywords:

“Nano Particles” , “Copper Complexes” , “Carbon Nanotubes” , “Click Chemistry Triazoles Keywords”