Aquatic Self-Assembly of Sixteen Subunits into a 39-kDa Dendrimer

We have developed the 8-(<i>m</i>-acetylphenyl)-2′-deoxyguanosine (mAG) scaffold for the self-assembly of supramolecules in water and for the synthesis of self-assembled dendrimers (SADs) in organic media. Previously, reported mAG assemblies showed promising characteristics for the construction of SADs. Yet, none of these SADs had large enough dendrons to reach a fractal geometry characteristic of high-generation dendrimers. Here we present the synthesis as well as the molecular and supramolecular characterization of a fourth-generation hydrophilic self-assembled hexadecameric dendrimer [mAGD<sub>4</sub>(OH)<sub>16</sub>]<sub>16</sub>·3KI (<b>3</b><sub>16</sub>) with a size and shape akin to those of globular proteins. The diameter of <b>3</b><sub>16</sub> (5.0 nm) was measured by pulsed field gradient NMR and dynamic light scattering experiments, which enabled the construction of a computer-generated molecular model. This SAD represents an attractive platform for biomedical applications due to its water solubility, discreteness, well-defined structure, thermal stability (<i>T</i><sub>m</sub> = 68 °C), and functional core.