Département de chimie moléculaire

Photoluminescent gold nanoclusters (Au NCs) were synthesized in one step in aq. conditions using a mixt. of glutathione and (monoor multivalent) glutathione modified arginine peptides. By controlling the ratio of coligands, the authors investigated how the multivalency and the amt. of arginines influenced the growth of Au NCs, their surface chem., their colloidal stability, and their optical properties. The authors demonstrated using two-dimensional NMR spectroscopy that the organization of the ligand on the Au surface was composed by an inner rigid layer and an outer flexible part via inter- and/or intraligand spatial proximity. This directly impacted the structure of the Au NCs, as confirmed by gel electrophoresis, high TEM, diffusion ordered spectroscopy and mass spectrometry. Increasing arginine content also induced an increase of pos. surface charge and an enhancement of the near IR emission intensity at ∼670 nm with quantum yield up to 10% validating the significant influence of the ligands to the optical properties of Au NCs.