Immobilization of a Copper Complex onto Magnetically Recoverable Amino-Functionalized Natural Asphalt for Catalytic Cross-Coupling Reactions; In Situ Fe to Fe ₃ O ₄ Conversion via Schikorr Reaction

We report a recyclable magnetic nanocatalyst, NA-Fe₃O₄@oxalic acid@Cu(II), designed for C-C and C-S cross coupling reactions. The catalyst was synthesized via the Schikorr reaction, enabling in situ growth of Fe₃O₄ on natural asphalt (NA) under mild conditions with hydrogen as a benign byproduct. NA provides a stable, carbon-rich support for strong metal anchoring, while oxalic acid stabilized Cu(II) and reduces leaching. The catalyst was characterized by FT-IR, SEM, EDX, TEM, TGA, BET, VSM, XRD, and AAS. The catalyst delivered consistently high yields across a broad range of aryl halides, including substrates bearing electron-donating and electron-withdrawing groups. The process is environmentally advantageous due to mild conditions, recyclability, and reduced waste. These features highlight its potential as a sustainable and cost-effective alternative to Pd-based systems.