Synthesis of Copper(II) Schif Base Complex Immobilized on Magnetite–Silica Nanoparticles and Using as a Reusable Catalyst for the Synthesis of 1‑Amidoalkyl‑2‑naphthols Under Ultrasonic Conditions

Abstract

In this research, a simple aliphatic –N2O2 Schif base ligand was synthesized and immobilized on magnetite–silica nano- particles. Supported tetradentate Schif base ligand was converted to Cu(II) Schif base complex as a result of a reaction with copper acetate salt. The Schif base ligand was synthesized by the condensation reaction between benzoyl acetone and ethylenediamine in a ratio of 2:1. Magnetite silica (Fe3O4@SiO2) nanoparticles were prepared and functionalized by –NH2 groups. This functionalization was done as a result of the reaction between magnetite–silica and 3-amino propyl triethoxysilane (APTES) in dry toluene. The immobilized Schif base ligand prepares through the condensation reaction between –NH2 groups of functionalized magnetite–silica and C=O groups of Schif base. So, the coordination mode of the immobilized Schif base is –N3O. Then immobilized Schif base was converted to Cu(II) complex. The immobilized Cu(II) complex was characterized by techniques such as FT-IR, VSM, XRD, FE-SEM, EDX, TGA-DTA, and AAS. The catalytic property of the nanoparticles was evaluated for the synthesis of the 1-amidoalkyl-2-naphthols. Magnetic solid base catalysts have great potential for easy catalyst separation with magnetic force, which reduces the catalyst loss and improves its post-reaction recovery. Besides, the small particle size with a high surface area also allows better interaction with reactants and improves the yields of the reaction