Preparation of a magnetic copper NNN pincer complex as an efficient catalyst in the synthesis of 4-(phenylethynyl) and 4-(4-phenyl-1H-1,2,3-triazol-5-yl)coumarin derivatives

Abstract

In this study, a 3-amino-trimethoxysilane-modified magnetic support was prepared and functionalized with furan-2-carbohydrazide through 2,4,6-trichloro-1,3,5-triazine as an organic linker to form a nitrogen rich pincer type ligand for copper coordination. The structure and morphology of the prepared nanocomposite (Fe3O4@SiO2-FCH (NNN pincer)/Cu) was confirmed with various techniques including FT-IR, FE-SEM, VSM, TEM, ICP, XRD, and EDX analysis. The amount of Cu in the nanocomposite was determined to be 9.9%wt. Then, its application in the synthesis of 4-(phenylethynyl)coumarin derivatives through CC bond formation between substituted 4-hydroxycoumarin and phenylacetylene derivatives was evaluated. After functionalizing of 4-position in 4-hydroxycoumarins with phenylacetylene derivatives, sodium azide was added and substituted 4-triazole-coumarins were synthesized in the presence of low amount of Fe3O4@SiO2-FCH (NNN pincer)/Cu nanocatalyst. The nanocatalyst was easy separated using of an external magnet and reused at least four run without reduction in its activity.