Gold nanoparticles from seeds: control of size and shape

Precise control of the size and shape of nanoparticles is increasingly recognized as an important topic because these quantities directly influence solid-state phenomena that are unique to the nanoscale. Accordingly, the establishment of such principles requires reliable synthetic routes to nanoparticles of predetermined size and shape. In this context, we have prepared gold nanoparticles of different size and shape using a recently developed method involving seeded growth, a very promising approach that separates the thermodynamically disfavored nucleation process from subsequent growth steps that occur spontaneously when monomers are added to existing nanoparticles seeds. With this new strategy it is possible to control size and shape of the resultant nanoparticles, properties that are extremely important for many applications but not easily achieved from other methods. The results demonstrate the possibility of controlling nanoparticle size and shape by careful fine tuning of the seeded growth method described. We are currently studying the relationship between the size of supported gold nanoparticle catalysts obtained by this method and their catalytic efficiency in a variety of important reactions, including Sonagashira coupling of phenyl acetylene and phenyl iodine and the hydroamination of alkenes and alkynes.