Synthesis of luminescent gold nano-clusters coated by N-acetyl-L-cysteine

New high luminescent thiolate-protected gold nano-clusters have been obtained by using a natural thiol, i.e. N-acetyl-L-cysteine (NALC). These gold nano-clusters were obtained by reacting HAuCl₄ with N-acetyl-L-cysteine in ethanol and NH₄OH was used to obtain a alckaline pH. Morphological and structural properties of this class of gold nano-clusters have been investigated by Transmission Electron Microscopy (TEM) and X Ray Diffraction (XRD). Optical properties have been studied by UV-visible spectroscopy and spectrofluorimetry.