Chemistry

Colloidal Construction Kit

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Science  09 Dec 2011:
Vol. 334, Issue 6061, pp. 1325
DOI: 10.1126/science.334.6061.1325-a

Total-synthesis approaches have made an art form of building complex organic molecules from much simpler and smaller pieces, using established rules of reactivity to selectively form specific products at each step. Colloidal particles are often described as “artificial atoms,” and hooking them together can produce “artificial molecules” that manifest combinations of useful optical, magnetic, catalytic, and electronic properties. However, synthetic strategies at this scale have largely been limited to fusing two particles together or growing a second particle on the surface of an existing one. Buck et al. have now developed a rational and stepwise approach for constructing hybrid nanoparticle oligomers. They started with Fe3O4 grown on Pt seed particles. The addition of a gold precursor surprisingly yielded Au-Pt-Fe3O4 as the exclusive trimetallic product. Using the same reaction method, the authors produced trimers in which the Au could be replaced by Ag, Ni, or Pd. A fourth component (PbS or mixed-valence CuxS) could also be added selectively, and the Au-Pt-Fe3O4 trimers could be fused into superdimers or higher-ordered branched nanostructures by heating in the presence of a trace quantity of sulfur.

Nat. Chem. 10.1038/NCHEM.1195 (2011).

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