A uniformly anchored zirconocene complex on magnetic reduced graphene oxide (rGO@Fe3O4/ZrCp2Clx (x = 0, 1, 2)) as a novel and reusable nanocatalyst for synthesis of N-arylacetamides and reductive-acetylation of nitroarenes

Abstract

In this study, a crafted zirconocene complex on rGO@Fe₃O₄ as a novel magnetic nanocatalyst was synthesized and then characterized using FT-IR, SEM, EDX, VSM, ICP-OES, TGA, BET and MS analyses. Next, catalytic activity of the prepared nanocomposite rGO@Fe₃O₄/ZrCp₂Cl_{x (x = 0, 1, 2)} towards successful reduction of aromatic nitro compounds to arylamines using N₂H₄·H₂O (80%) was investigated. The examined nanocatalyst also showed perfect catalytic activity for reductive-acetylation of aromatic nitro compounds to the corresponding N-arylacetamides without isolation of the prepared in situ amines using the N₂H₄·H₂O/Ac₂O system. Furthermore, acetylation of the commercially available arylamines to the corresponding N-arylacetamides was carried out by acetic anhydride in the presence of the rGO@Fe₃O₄/ZrCp₂Cl_{x (x = 0, 1, 2)} nanocomposite. All reactions were carried out in refluxing EtOH as a green solvent to afford the products in high yields. The obtained results exhibited that the nanocomposite of rGO@Fe₃O₄/ZrCp₂Cl_{x (x = 0, 1, 2)} showed a great catalytic activity in comparison to rGO and rGO@Fe₃O₄ as the parent constituents. Recovery and reusability of rGO@Fe₃O₄/ZrCp₂Cl_{x (x = 0, 1, 2)} were also examined for 8 consecutive cycles without significant loss of the catalytic activity. This establishes the sustainable anchoring of the zirconocene complex on the surface and mesopores of the rGO@Fe₃O₄ nanohybrid system.