Two strategies for the self-assembly of gold nanoparticles: Photoreaction and radical reaction.

Gold nanoparticles modified with a newly synthesized cinnamate moiety (CI-AuNPs) were prepared using the phase method. The cinnamate moiety, which is well known for its photoreactive properties, could be reacted by means of radical attack and UV irradiation. Crosslinking of this moiety by the two reactions causes aggregation of the CI-AuNPs, which demonstrates the feasibility of fabricating self-assembled spherical structures by means of chemical crosslinking of gold nanoparticles through two distinct mechanisms, namely, photocycloaddition and radical reaction upon addition of an initiator. Both methods yielded monodispersed spherical CI-AuNPs assemblies, and especially the radical-induced system showed the ability to construct linear-chain structures. Here, we suggest the preparation of gold nanoparticles modified with a simply synthesized photoreactive group and their self-assembly via two selective strategies (photoreaction and radical reaction). We expect that this study will contribute to the strategic fabrication of self-assembled nanostructures.