Two novel polyelectrolytes were obtained by chemical modification of poly(4-acryloyloxybenzaldehyde) using o-and p-aminophenylsulfonic acid, the characterization shows a chemical modification of 24.38 and 63.33%, respectively. The study shows that the polyelectrolyte with sulfonic acid in para position reduces metal ions more rapidly than polyelectrolyte in ortho position. The obtained nanoparticles of Au and Ag were characterized by ultraviolet-visible absorption spectroscopy (UV-vis) and transmission electron microscopy. The results showed that these ionic polymers are not only capable of reducing gold and silver ions, but also can stabilize the nanoparticles in the colloidal solutions. With these polymers, the process of metallic ions reduction is very slow and they lead to the production of Au and Ag nanoparticles with quasi-spherical shapes which are stable in colloidal solutions for several months. The advantage of the method used here is that the reduction can be realized in water at room temperature.

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DFT calculations were carried out in order to determine the electronic and structural properties of pentagonal Al (I and D symmetries), Al -CO, and Al -NO clusters, where n = 7, 13, 19, 43, or 55 atoms. As n was increased, the bare clusters were found to exhibit a transition in electronic behavior (from semiconductor to conductor) at n = 43 atoms. Clusters with a bound CO or NO molecule also showed this behavior, although their HOMO-LUMO energy gaps were smaller than those for the corresponding bare clusters. As the size of the Al -CO or Al -NO cluster increased, the presence of extra p electrons improved the capacity of the cluster to adsorb a CO or NO molecule and resulted in an increase in the electronic charge directed from the aluminum atom at the adsorption site to the adsorbed species (CO or NO), thus strengthening the Al-CO or Al-NO bond. Furthermore, the Al CO and Al NO clusters with n = 43 and 55 exhibited chemisorption, as did the Al-NO cluster; the other clusters presented physisorption, based on their adsorption energies. The tendency to adsorb either CO or NO increased with the size of the aluminum cluster. Graphical Abstract Adsorption of CO and NO molecules onto pentagonal clusters of aluminum: a DFT study.

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