Constructing Hybrid Nanoparticles

To create complex colloidal hybrid nanoparticles—materials with various types of nanoparticles fused together—nanoscience researchers at Pennsylvania State University are taking a cue from their colleagues in organic synthesis. Guided by mechanistic considerations, Raymond E. Schaak, Matthew R. Buck, and James F. Bondi use chemical transformations to tack together simpler pieces of the structure in a predictable manner (Nat. Chem., DOI: 10.1038/nchem.1195). “We are trying to bring the elegance of organic total synthesis to the world of inorganic nanostructures,” Schaak tells C&EN. “We approach the synthesis in a stepwise manner; identify plausible reaction mechanisms; and develop, define, and exploit unique solid-state analogs of concepts that underpin organic synthesis but that are not typically in the nanomaterials chemist’s toolbox, such as chemoselective and regioselective reactions, coupling chemistry, and substituent effects.” For example, the researchers create gold-platinum-iron oxide hybrid nanoparticles from the reduction of gold ions in the presence of Pt-Fe₃O₄. One might expect the resulting gold nanoparticle to fuse to the Pt, the Fe₃O₄, or both regions of the particle, but the Penn State team found that the gold particle fused exclusively to Pt, demonstrating regioselectivity in their synthetic scheme.