PAMAM Dendrimers as Support for the Synthesis of Gold Nanoparticles: Understanding the Effect of the Terminal Groups

The interaction between hydroxyl-, aldehyde-, and amino-terminated PAMAM G0 dendrimers with gold nanoclusters Aun (n = 2, 4, 6, and 8) was studied theoretically at the DFT level. Different coordination sites were explored, including internal and superficial coordination. In the case of amino terminated PAMAM, the most stable complexes exhibited external coordination, while hydroxyl and aldehyde-terminated dendrimers did not favor interaction with the terminal groups, showing lower binding energies. Hydroxyl-terminated PAMAM, as well as its oxidized form, have lesser capacity as stabilizing capping agent of gold nanoclusters, agreeing with previous experimental reports. The vertical first ionization potential, electron affinity, Fermi level, and the HOMO–LUMO gap of PAMAM and Aun–PAMAM G0 complexes were also analyzed.