The structures and molecular interactions of (R)nN-CO2 complexes of amines and CO2 in the gas phase were computationally studied by using ab-initio methods and quantum theory of atoms in molecules (QTAIM). The analysis of the electrostatic potential showed that the interaction N∙∙∙C present in this type of aggregates is favored by the potential difference between the N and C atoms. On the other hand, it was observed the interaction energy is being more exergonic in molecular aggregates having highly substituted amino groups and cyclic structure; in addition, the geometric deformation of CO2 and other additional molecular interactions facilitate the process of complexation of this gas. The QTAIM analysis showed that the interaction N∙∙∙C has an electrostatic character and its strength increases with the substitution of the amino group.

In the present work was performed a quantitative structure-activity relationship (QSAR) for a set of derivatives of 1,4-quinoxaline N-oxides with antichagasic activity based on reactivity descriptors from the frame conceptual DFT. QSAR models showed a good statistical quality and capacity internal prediction with R2 > 0.6 and Q2> 0.5 respectively. QSAR model suggest that antichagasic activity of the studied compounds depends largely from the reactive behavior of N-oxide group (N-O). Also, reactivity descriptors showed that the N-oxide group is a reactive site in theses derivatives with nucleophilic characteristics. The results QSAR shed light on the understanding of the mechanism of action and design of new drugs based on derivatives of 1,4-di-N-oxides quinoxaline.

We used conceptual DFT to study global and local reactivity of both nonfunctionalized and functionalized activated carbons, with groups -OH,-CHO, -NH2, -COOH, and -CONH2. Electron-withdrawing groups were observed to increase the reactive surface, while electro-donating groups increase stability as reactivity of the activated carbon decreases. Descriptor groups were used to study the reactivity of structural fragments of activated carbons. The electrophilic and nucleophilic sites indicate that the carbon surface has an amphiphilic behavior that allows it to be used as an adsorbent material for a variety of molecules.