The antioxidant power of eugenol and vitamin C was examined by analyzing the ability of these ligands to bind to the NADPH oxidase protein target and evaluating their bond interactions with critical residues. The results confirm that docked ligands are more stable in the specified active region of 2CDU during a MD simulation of 100 ns and 2CDU protein-ligand interactions with docked ligands showed significant hydrogen bond, hydrophobic, and water bridge formation. Eugenol exhibits hydrogen bond interactions with critical residues in the selective pocket in comparison to vitamin C. Also, eugenol had a similar binding orientation and very considerable stability in the selective pocket of 2CDU with a high binding energy with lipophilic energy. The electrostatic potential maps indicate that for eugenol, the –OH and –OCH3 sites, while that the –OH and –CO functional groups in vitamin C are responsible of the antioxidant activities of these compounds. HAT and SET mechanisms suggest that eugenol may become a better antioxidant than vitamin C.

ABSTRACT In this work, a computational chemical study of Etoricoxib was carried out at the X/6311G(d,p) (where X=B3LYP, M06 and ωB97XD) level of theory, at the gas, aqueous and ethanol phases. Through the chemical reactivity descriptors derived from the DFT, it was possible to find that Etoricoxib structure exhibits a major chemical activity in water and ethanol phases in comparison to the gas phase, which suggests this drug would be more active in biological solvents like in blood, tissues and places where the ciclooxigenasa 2 (COX)-2 is found. In addition, a molecular docking analysis was conducted to study the interaction of Etoricoxib with the COX-2 active site. The results suggest that Etoricoxib interacts with 19 amino acid residues inside the COX-2 active site.

In the present work, the chemical reactivity of indaziflam N-[(1R,2S)-2,3-dihydro-2,6-dimethyl-1H-inden-1 yl]-6-[(1R)-1-16 fluoroethyl]-1,3,5-triazine-2,4-diamine so called indaziflam (IND) and its metabolites: triazine indanone (ITI), indaziflam carboxylic acid (ICA) and fluoroethyldiaminotriazine (FDAT) was analyzed. The calculations were performed at the X/6 311++G(2d,2p) (where X=B3LYP, M06, M06L and wB97XD) level of theory, in the aqueous phase. The results indicate that ITI is the more reactive followed by ICA, IND and FDAT. The distribution of the active sites was determined evaluating the Fukui function employing the frozen core and finite difference approximations. For electrophilic attacks, IND shows the more reactive zone on the benzene ring, ITI and ICA on the nitrogen atom in the central section and FDAT on its nitrogen atoms. The more nucleophilic sites for IND are observed on the carbon atoms of triazine, on the carbonyl group for ITI, on the carboxylic group for ICA, and on the nitrogen atoms of triazine for FDAT. For free radical attacks case, the more reactive sites for IND are on the benzene and triazine rings, on the carbonyl group, nitrogen of the central section, and nitrogen atoms of triazine, for ITI, carboxylic group for ICA, and on the nitrogen atoms of triazine ring for FDAT.

In this work we have calculated global and local DFT reactivity descriptors for tartrazine at B3LYP/6-311++G (2d,2p) level. Global reactivity descriptors such as ionization energy, molecular hardness, electrophilicity, and total energies were calculated to evaluate the tartrazine reactivity in aqueous and gas conditions. Local reactivity was evaluated through the Fukui function. The influence of the solvent was taken into account with the PCM model. The results indicate that the solvation process modifies the reactivity descriptors values. From our results, it was found that an electrophilic attack allows a direct cleavage of the N=N bond. If a nucleophilic attack is considered as initial attack, it is necessary a second attack by free radicals or electrophiles to cleave the N=N bond. In the case of an initial attack by free radicals, tartrazine requires a subsequent nucleophilic attack to cleave the N=N bond.

En este trabajo se han calculado descriptores globales y locales de reactividad TFD para la tartrazina en el nivel B3LYP/6-311++G (2d,2p). Los descriptores globales de reactividad tales como energía de ionización, dureza, electrofilicidad y energías totales se calcularon para evaluar la reac-tividad de la tartrazina en medio gaseoso y acuoso. La reactividad a nivel local se evalúo a través de la Función Fukui. La influencia del solvente se tomó en cuenta mediante el modelo PCM. Los resultados indican que el proceso de solvatación modifica los valores de los descriptores de reactividad. A partir de nuestros resultados, se encontró que un ataque electrofílico permite una ruptura directa del enlace N=N. Si se considera inicialmente un ataque nucleofílico, entonces es necesario un segundo ataque mediante radicales libres o electrofilos para romper el enlace N=N. En el caso de un ataque inicial por radicales libres, se requiere un subsecuente ataque nucleofílico para lograr la ruptura del enlace N=N.

An electrochemical study of Co electrodeposition onto polycrystalline Pt from an aqueous solution containing 10-2 M CoCl2 + 1 M NH4CI (pH = 9.3) was conducted at overpotential conditions. The current density transients showed two maxima that corresponded to two nucleation and growth processes. The entire transient behavior was adequately predicted considering the contribution to the total current of four different processes: a Langmuir-type adsorption process, a diffusion-controlled two-dimensional instantaneous nucleation, and two three-dimensional nucleation and growth processes.

In present work we analyzed some electronic properties involved during the adsorption of BH4- on Cu(100), Ag(100) and Au(100) surfaces. Reactivity descriptors such as ionization energy, hardness, electrophilicity, frontier molecular orbitals, condensed Fukui function, adsorption energies and density of states were calculated to identify changes in the reactivity on Cu(100), Ag(100) and Au(100). The results suggest the BH4- adsorption is favored on Cu(100) more than on Ag(100) or Au(100). The BH4- -Au(100) system showed higher values of μ and ω in comparison with BH--Ag(100) and BH4- Cu(100) systems. Last results suggest that gold is a better electron acceptor in comparison with silver and copper. Also, the fraction of electrons transferred during the BH4- adsorption was calculated indicating a bigger electron transfer from BH4- to Cu(100) compared to Au and Ag.

En el presente trabajo analizamos algunas propiedades electrónicas involucradas durante la adsorción del BH4- sobre las superficies Cu(100), Ag(100) y Au(100). Se calcularon descriptores de reactividad tales como energía de ionización, dureza, electrofilicidad, orbitales moleculares frontera, función Fukui condensada, energías de adsorción y densidad de estados, para identificar cambios en la reactividad de las superficies Cu(100), Ag(100) y Au(100). Los resultados sugieren que la adsorción del BH- es favorecida sobre Cu(100) más que sobre Ag(100) y Au(100). El sistema BH4- -Au(100) mostró los valores mayores de μ y ω en comparación con los sistemas BH4- -Ag(100) y BH4- -Cu(100). Estos resultados sugieren que el oro es un mejor aceptor de electrones que plata o cobre. También se calculó la fracción de electrones durante el proceso de adsorción, los resultados indicaron que existe una mayor transferencia de carga del BH- hacia el cobre comparada con las obtenidas en Au y Ag.

In present work, we analyzed the copper electrodeposition onto GCE (System I) and HOPGE (System II) from perchlorate solutions. The current density transients obtained from system I and II were well described through a kinetic mechanism that involves four different contributions: (a) a Langmuir type adsorption process, b) an electron transfer from Cu2+→Cu+, (c) a 3D nucleation limited by a mass transfer reaction and (d) a proton reduction process. It was observed that the values of the nucleation rate, the number of active nucleation sites were increased with the overpotential and they are bigger onto GCE in comparison with HOPGE.

In the present work we calculated reactivity descriptors for atrazine at MP2/6-311++G(2d,2p)//B3LYP/6-311++G(2d,2p) level in order to analyze its reactivity. Reactivity descriptors such as ioniza-tion energy, molecular hardness, electrophilicity, condensed Fukui function and total energies were determined to identify changes in the reactivity of atrazine in the gas and aqueous phases. The influence of the solvent was taken into account with the PCM model. The values of the reactivity descriptors indicated that the interaction of atrazine with water diminished its reactivity in comparison with the exhibited in gas phase. Also, it was found that the electrophilic and free radical attacks were equivalent and they were located on all the cases in the ethylamine and isopropylamine groups.

En el presente trabajo calculamos descriptores de reactividad para la atrazina, en el nivel de teoría MP2/6-311++G(2d,2p)//B3LYP/6-311++G(2d,2p), con la intención de analizar su reactividad. Se calcularon descriptores tales como energía de ionización, dureza, electrofilicidad, funciones de Fukui y diferencias de energías para identificar los cambios de reactividad de la atrazina en fase gas y en fase acuosa. La influencia del disolvente se tomó en cuenta empleando el modelo PCM. Los descriptores de reactividad calculados sugieren que en agua la reactividad de la atrazina disminuye en comparación con la atrazina en fase gas. Se encontró que las reactividades, electrofilica y por radicales libres, en la atrazina son equivalentes y localizadas en todos los casos en los grupos etilenamina e isopropilamina.

It was carried out an electrochemical study of the cobalt electrodeposition onto HOPG electrode from an aqueous solution containing 10-2 M of CoSO4 + 1M (NH4)2SO4. Nucleation parameters such as nucleation rate, density of active nucleation sites, saturation nucleus and the rate constant of the proton reduction reaction (kPR) were determined from potentiostatic studies. An increase in kPR values with the decrease in the applied potential suggested a competition between H+ and Co2+ by the active sites on the surface. The ΔG energy calculated for the formation of stable nucleus was 8.21x10-21 J/nuclei. The AFM study indicated the formation of small clusters of 50-400 nm in diameter and 2-120 nm in height.

We carried out an electrochemical study of the cobalt electrodeposition onto glassy carbon electrode from an aqueous solution containing 10-2 M of CoSO4 + 1 M (NH4)2SO4 at natural pH 4.5. The potentiostatic study indicated a progressive 3D nucleation and growth during the deposition process. The average diffusion coefficient calculated for this system was 2.65 X 10-6 cm² s-1 while the ΔG for the formation of stable nucleus was 6.50 X 10-20 J/nuclei. The scanning electron microscopy images indicated the formation of small and homogeneous nucleus onto GCE of approximately 300 nm.