Review of gold-ligand interactions: Implications for metallurgical processes and nanoparticle synthesis

Gold, essential in both metallurgical extraction and nanoparticle-based technologies, plays a central role in catalysis, sensing and biomedicine. Its interactions with organic ligands are critical for efficient gold recovery through flotation and leaching as well as for synthesizing gold nanoparticles. These interactions, primarily governed by anchoring atoms, sulfur, nitrogen, phosphorus, oxygen, and carbon, define the strength, geometry and selectivity of the gold-ligand interface. This review evaluates how each anchoring atom affects adsorption mechanisms, including chemisorption, donor-acceptor interactions and dispersive forces in metallurgical and nanoparticle contexts. Sulfur-based ligands, essential in flotation and leaching, form strong AuS bonds at high-coordination atop/hollow sites or undercoordinated adatoms, modulated by redox conditions. Nitrogen-based ligands, less effective in extraction, are vital in nanoparticle synthesis due to selective binding to gold adatoms. Phosphorus-based ligands, weaker in extraction, hold promise for nanoparticle engineering, leveraging electronic and steric properties. Oxygen-anchoring ligands with weak AuO interactions have limited relevance in extraction but stabilize nanoparticles via multidentate and non-covalent interactions. Carbon-based ligands, especially N-heterocyclic carbenes, create highly stable AuC bonds, crucial for nanoparticle synthesis despite limited extraction use. The review advocates an interdisciplinary approach to advance fundamental understanding and practical applications of gold technologies. Bridging metallurgical and colloidal-interface perspectives provides valuable insights for improving gold recovery methods and developing innovative gold-based nanomaterials for diverse advanced applications.