Ionic Liquid Assisted Fabrication of Nanostructures of CuO for Catalytic Uses in Reduction of Nitroarenes

Herein, varied structural arrangements of CuO nanoparticles (NPs) were synthesized using Brønsted‐acidic 2‐methyl‐1,3‐disulfoimidazolium [MDSIM] ⁺ ionic liquids of different anions ([OAc] ⁻ , [BF ₄ ] ⁻ , and [PF ₆ ] ⁻ ) for in situ generation of complex anionic speciation [BF ₄ .Cu(OAc) ₂ ] ⁻ /[PF ₆ .Cu(OAc) ₂ ] ⁻ /Cu(OAc) ₃ ] ⁻ as precursor templates after reaction with hydrated copper acetate in solvent‐free grinding method. The structural differences of CuO NPs were identified by analytical techniques. High‐resolution transmission electron microscope images showed their unique morphological nanostructures as nanospheres, well‐dispersed nanocapsules, and a fiber‐like network against the anions [OAc] ⁻ , [BF ₄ ] ⁻ , and [PF ₆ ] ⁻ of ionic liquids, respectively. Their observed bandgap variations from Tauc plots evidenced the effects of anions of ionic liquids on fabricating the optical properties of CuO NPs as porous materials. The reactivity of these nanoparticles was investigated as efficient recyclable heterogeneous catalysts for reduction of nitroarenes to arylamines in aqueous medium at mild reaction conditions.