Controllable assembly of dimers and trimers of gold Nanoparticle bridged by Tris(2-aminoethyl)amine.

In this paper, dimer and trimer assemblies were prepared through covalent coupling of the monomer, i.e., carboxyl monofuntional gold nanoparticles using Tris(2-aminoethyl)amine (Tren) as a bridging ligand. TEM examination showed that the dimer structures could be obtained with an increased yield using Tren instead of ethylenediamine (EDA) as a bridging molecule without N,N'-Diisopropylcarbodiimide (DIC) in reaction solution. Comparatively, the main trimer structures were obtained when DIC was added into reaction solution. The absorption spectra showed the red shift of the surface plasmon resonance (SPR) from monomer to trimer due to dipole-dipole interaction between proximate particles.