Dendritic Arenethiol-Based Capping Strategy for Engineering Size and Surface Reactivity of Gold Nanoparticles

The report describes a strategy for the synthesis of gold nanoparticles for which size and surface reactivity of the particles are controlled by the molecular sizes of dendritic arenethiols (DAT) as capping agents. This strategy exploits two important attributes of the DAT molecules: one involving the utilization of the umbrella-like structure with a single thiol as the anchorage handle and the other involving the rib with an expandable dendritic structure as a spacing-tunable cap. The synthesis of gold nanoparticles with controllable sizes below 10 nm has been demonstrated using different sizes of DAT in both one-phase and two-phase solutions. The unique structural properties of the dendritic arenethiol capping molecules not only enable the ability to control size growth of gold nanoparticles but also ready surface exchange reaction for surface derivatization and interparticle assembly. The viability of this strategy for the control of size and surface reactivity has been demonstrated by results from the structural and morphological characterizations of the nanoparticles and assemblies.