Resumen Las celdas solares orgánicas (OSC) son una de las mejores alternativas en el area fotovoltaica. Estos dispositivos convierten directamente la luz solar en corriente eléctrica con eficiencias razonables. El componente más importante de una OSC es la capa activa fotoconductora que puede estar hecha de moléculas orgánicas. En este estudio teórico, se aplicó un enfoque químico cuántico para calcular propiedades de cuatro moléculas orgánicas, como la energía del orbital molecular ocupado más alto (HOMO) y el orbital molecular desocupado más bajo (LUMO), la brecha de energía LUMO-HOMO y los cambios químicos teóricos de 1H NMR (este último solo para una molécula). La optimización de la geometría de las cuatro moléculas pequeñas y los cálculos correspondientes se realizaron utilizando el software Gaussian 09 mediante la Teoría Funcional de la Densidad (DFT) en el nivel teórico B3LYP/6-31G(d). Los valores experimentales encontrados en la literatura fueron comparados con los valores teóricos obtenidos mediante un análisis de regresión lineal. Este estudio computacional mostró una buena concordancia con los datos experimentales, el análisis de regresión mostró un coeficiente de determination superior a 0.99.

Abstract Organic solar cells (OSCs) are one of the best alternatives in the photovoltaic area. These devices convert directly sunlight into electrical current with reasonable efficiencies. The most important component of an OSC is the photoconductive active layer which can be made of small organic molecules. In this theoretical study, a quantum chemical approach was applied to calculate the properties such as the energy of Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO), LUMO-HOMO energy gap, and the theoretical 1H NMR chemical shifts (the latter only for one molecule) for four organic molecules that exist in the literature. The geometry optimization of the four small molecules and the corresponding calculations were performed using Gaussian 09 software by means of the Density Functional Theory (DFT) at the B3LYP/6-31G(d) theoretical level. All the reported experimental values given in the papers were compared with the obtained theoretical values via a linear regression analysis. Our computational study showed good agreement with the experimental data as the regression analysis showed a coefficient of determination greater than 0.99.

Chalcones are open chain molecules precursors of flavonoids and isoflavonoids, found spread in edible plants. Because they are easily accessible trough Claisen Shmidt condensation, a great variety of derivatives are available. They have also shown potential in pharmacological and biological applications. It is known that chalcone derivatives display a role in the treatment of complex diseases such as cancer, among others, where the DNA is considered as the target for the action of these kinds of compounds. This action is commonly explained as the inhibition of the DNA replications and transcriptions through interactions. However, not conclusive associations between these DNA-Drug interactions and toxicity have been found. This research focuses on the capacity of a chalcone`s family to interact with DNA. Therefore, the binding constants for each compounds with Calf Thymus DNA [CT-DNA] were determined by spectrophotometric titration at room temperature. In addition, the effect of increasing the chalcone`s concentration over the relative viscosity of CT-DNA at room temperature was assessed. On the other hand, with the aim to find the optimal DNA-chalcone configurations, as well as consistently predict their binding, a computational work was undertaken. To accomplish these goals within a reasonable time framework, an empirical scoring function (AScore) and a docking engine (ShapeDock) were performed using the ArgusLab package. The results of viscosity and docking measurement provided structural insights which suggest that chalcones bind with DNA via interaction as well as intercalation. The presence of interactions is also evidenced by the spectrophotometric study which showed luminescence quenching of the chalcones upon interaction with CT-DNA.

(E)-2-{[(2-Aminopyridin-3-yl)imino]-methyl}-4,6-di-tert-butyl-phenol ( 3: ), a ligand containing an intramolecular hydrogen bond, was prepared according to a previous literature report, with modifications, and was characterized by UV-vis, FTIR, ¹H-NMR, 13C-NMR, HHCOSY, TOCSY and cyclic voltammetry. Computational analyses at the level of DFT and TD-DFT were performed to study its electronic and molecular structures. The results of these analyses elucidated the behaviors of the UV-vis and electrochemical data. Analysis of the transitions in the computed spectrum showed that the most important band is primarily composed of a HOMO→LUMO transition, designated as an intraligand (IL) charge transfer.