Poly(N‐2‐Aminoethylacrylamide)‐Cu(I) Chelate Grafted from Fe₃O₄@SiO₂ Core‐Shells for the Selective Monoarylation of Anilines via the Ullmann Reaction

Abstract

The present work describes the grafting of a polymer‐metal chelate (PMC) from Fe3O4@SiO2 core‐shells via the Surface Initiated‐Atom Transfer Radical Polymerization (SI‐ATRP). The magnetic core‐shells were silylated by 2‐bromo‐2‐methyl‐N‐(3‐(trimethoxysilyl)propanamide (BTPAm) to give the surface‐anchored ATRP initiator. Acrylamide was polymerized from the Fe3O4@SiO2 surface via the ATRP approach. The grafted magnetic nanoparticles were trans‐amidated with ethylenediamine to give poly(N‐2‐aminoethylacrylamide) grafted magnetic core‐shells, Fe3O4@SiO2‐g‐PAE‐AAm. The grafted chelating polymer ligand (CPL) was treated with an acetonitrile solution of CuI to afford the Fe3O4@SiO2‐g‐PAE‐AAm−Cu(I). The grafted PMC was characterized by FT‐IR, CP/MAS 13C NMR, and thermo‐gravimetric analysis (TGA). The grafted PMC catalyzed the N−C bond formation via the Ullmann‐type N‐arylation reaction of haloarenes and anilines under optimal reaction conditions. Mono N‐arylation product was obtained as the major product with excellent selectivity. The excellent recyclability of the catalyst was shown by negligible deactivation over six runs.