Novel Hybrid Thioamide Ligand Supported Copper Nanoparticles on SBA-15: A Copper Rich Robust Nanoreactor for Green Synthesis of Triazoles and Tetrazoles in Water Medium

Abstract

In this work, a new thioamide based ligand with reductive nature was designed for modification of mesoporous SBA-15. For this purpose, the channels of SBA-15 were modified with Tris(2-aminoethyl)amine (TAEA) groups and then reacted with S8 and phenyl acetylene to form thioamide groups via Willgerodt-Kindler reaction. This porous material proved to be an effective host for the immobilization of inexpensive Cu(II) ions. The catalytically active Cu(I) species were generated automatically due to the reductive nature of thioamide modified surface of catalyst without use of any toxic reducing agents. The well stabilized Cu(I) species into the nano-channels of SBA-15 were used for synthesis of various triazoles from sodium azide, phenyl acetylene and alkyl/benzyl halides or alkyl epoxides and various tetrazoles from sodium azide and aryl/alkyl nitriles under green mild aqueous reaction conditions. This catalytic system was used for 9 and 11 consecutive runs for synthesis of triazoles and tetrazoles, respectively.