Histidinehydroxamic acid as new biomolecule to produce molecular-like fluorescent gold nanoclusters: Possible mechanisms for metal ion sensing

•Hydroxamic acid-stabilized gold nanoclusters (Au NCs) were produced for the first time.•Few-atomic nanostructures possess intense blue emission with quantum yield of 4%•Chelating hydroxamate moiety on NCs’surface is effective to design metal ion sensors.•Copper ions can exchange the ligand from the surface causing fluorescence quenching.•Fluorescence enhancement is detected for coordinating zinc ions on metallic surface.