An asymmetric Salamo-based Zn complex supported on Fe3O4 MNPs: a novel heterogeneous nanocatalyst for the silyl protection and deprotection of alcohols under mild conditions

Abstract

In this study, a magnetic asymmetric Salamo-based Zn complex (H₂L = salen type di-Schiff bases)-supported on the surface of modified Fe₃O₄ (Fe₃O₄@H₂L-Zn) as a new catalyst was designed and characterized via numerous analytical techniques such as FT-IR spectroscopy, XRD, EDS, ICP-AES, SEM, TEM, TGA and VSM. An efficient and sustainable synthetic protocol has been presented for the synthesis of silyl ether substructures via the silyl protection of alcohols under mild conditions. The synthetic protocol involves a two-component solvent-free reaction between various hydroxyl-bearing substrates and hexamethyldisilazane (HMDS) as an inexpensive silylating agent using Fe₃O₄@H₂L-Zn MNPs as a magnetically separable, recyclable and reusable heterogeneous catalyst. Fe₃O₄@H₂L-Zn MNPs were also applied for the removal of silyl protecting groups from hydroxyl functions using water in CH₂Cl₂ under green conditions. The catalyst demonstrated good to excellent catalytic yield efficiency for both the reactions compared to the commercial metal-based catalysts under green conditions for a wide range of substrates.