Preparation of very reactive thiol-protected gold nanoparticles: revisiting the Brust-Schiffrin method

The preparation and properties of tert-dodecanethiol protected gold nanoparticles amenable to very rapid surface functionalization by associative mechanism is described. The new material can be easily prepared by controlling the reaction time, because only a limited but enough number of tert-dodecanethiol to stabilize the gold clusters is bond to the surface until about an hour. Accordingly, it can be isolated as a solid and handled much like the highly stabilized Brust-Schiffrin analogues, but reacted very rapidly with any molecular species containing one or multiple functional groups such as thiol, disulfide, pyridine, etc. These characteristics are ideal for the preparation of a variety of new organic-inorganic hybrid nanomaterials by coordinative self-assembly. This possibility was illustrated using meso-tetra(4-pyridyl)porphyrin, which promptly bonded to the reactive protected gold nanoparticles generating a solid that can be grown as thin films with layer-by-layer control on a suitably modified surface.