Copper(II) complex of (±)trans-1,2-cyclohexanediamine azo-linked Schiff base ligand encapsulated in nanocavity of zeolite–Y for the catalytic oxidation of olefins

Abstract

A Schiff base ligand derived from 4-(benzeneazo) salicylaldehyde and (±)trans-1,2-cyclohexanediamine (H₂L) and its corresponding Cu(II) complex (CuL) has been synthesized and characterized by FT-IR, UV-VIS and ¹H NMR. The copper Schiff base complex encapsulated in the nanopores of zeolite-Y (CuL-Y) by flexible ligand method and its encapsulation have been ensured by different studies. The homogeneous and its corresponding heterogeneous catalysts have been used for oxidation of different alkenes with tert-butyl hydroperoxide. Under the optimized reaction conditions, the oxidation of cyclooctene, cyclohexene, styrene and norbornene catalyzed by CuL gave 89, 63, 46 and 13% conversion, respectively. These olefins were oxidized efficiently with 50, 96, 96 and 92% conversion in the presence of CuL-Y, respectively. Comparison of the catalytic behavior of CuL and CuL-Y showed the higher catalytic activity and selectivity of the heterogeneous catalyst with respect to the homogenous one.