Examinando por Autor "Salgado-Morán, Guillermo"
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Ítem A DFT study of the chemical reactivity of cimetidine A, C and D in the gas phase and in H2O, MeOH and EtOH solvents(Serbian Chemical Society, 2017) Huizar, Luis Humberto Mendoza; Salgado-Morán, Guillermo; Cardona-Villada, Wilson; Pacheco, Alison Geraldo; Glossman-Mitnik, DanielIn the present work, the chemical reactivity of cimetidine A, C and D in different solvents was analyzed through the evaluation of global and local DFT reactivity descriptors. In the gas, MeOH and EtOH phases, cimetidine A, C and D exhibit energy differences of 3-11 kcal∗∗ mol-1. However, in the aqueous phase, cimetidine A and D are approximately isoenergetic. The values of the hardness indicate that cimetidine A, C and D are more reactive in the presence of a solvent than in the gas phase. In addition, the results suggested that CimC and CimD are better nucleophiles that CimA. The values of the Fukui function suggest that the more reactive sites of CimA are not modified in the different solvents. In the case of CimC, the more reactive sites to electrophilic and free radical attack are located on the thioether sulfur. For CimD, the number and place of the electrophilic and free radical sites are independent of the solvent.Ítem DFT study of polythiophene energy band gap and substitution effects(Hindawi Publishing Corporation, 2015) Bouzzine, Si. Mohamed; Salgado-Morán, Guillermo; Hamidi, Mohamed; Bouachrine, Mohammed; Pacheco, Alison Geraldo; Glossman-Mitnik, DanielPolythiophene (PTh) and its derivatives are polymer-based materials with a π-conjugation framework. PTh is a useful photoelectric material and can be used in organic semiconductor devices, such as PLED, OLED, and solar cells. Their properties are based on molecular structure; the derivatives contain different substitutes in the 3 and 5 positions, such as electron-donating or electron-withdrawing groups. All molecular geometries were optimized at B3LYP/6-31G(d,p) level of theory. The energy gap (Egap) between the HOMO and LUMO levels is related to the π-conjugation in the PTh polymer backbone. In this study, the DFT calculations were performed for the nonsubstituted and 3,5-substituted variants to investigate the stability geometries and electrical properties. The theoretical calculations show that the substituted forms are stable, have low Egap, and are in good agreement with the experimental observations. © 2015 Si. Mohamed Bouzzine et al.Ítem Fractal dimension calculation of a manganese-chromium bimetallic nanocomposite using image processing(Hindawi Publishing Corporation, 2015) Lashgari, Amir; Ghamami, Shahriar; Shahbazkhany, Saeedeh; Salgado-Morán, Guillermo; Glossman-Mitnik, DanielBimetallic materials, which have the ability to convert heat change into mechanical movement, normally consist of two bonded strips of dissimilar metals that expand at different rates. We describe how we made a manganese-chromium (Mn-Cr) bimetallic nanocomposite using the centrifuge method and a low-to-high approach. We conducted scanning electron microscope (SEM) imaging, energy-dispersive X-ray spectroscopy (EDX) analysis, and X-ray diffraction spectra of the nanocomposite to prove its identity. We examined how centrifuge speed, process time, and the use of an "intruder agent" affected the properties of the material. The fractal dimension is a significant factor that can be used to approximate the surface roughness, the texture segmentation, and an image of the studied compounds. We calculated the technique of fractal dimensions using image-processing values on a computer and histogram plot with the SEM image of the Mn-Cr bimetallic nanocomposite using MATLAB sofware. We applied the Statistical Package for the Social Sciences sofware for statistics data extracted from the SEM image of the nanocomposite and obtained the following results: mean = 1.778, median = 1.770, max = 1.98, min = 1.60, skewness = 0.177, range = 0.38, and harmonic mean = 1.771 for fractal dimension of the SEM image. © 2015 Amir Lashgari et al.Ítem Morphological Investigation and Fractal Properties of Realgar Nanoparticles(Hindawi Publishing Corporation, 2015) Lashgari, Amir; Ghamami, Shahriar; Bahrami, Zahra; Shomossi, Farzaneh; Salgado-Morán, Guillermo; Glossman-Mitnik, DanielSome arsenic compounds can show extraordinary polymorphism. Realgar (As4S4) is among several minerals with various crystal forms and is one of the most important sources of arsenic for pharmaceutical use. Currently, realgar is used as an arsenic source in many industries, such as weaponry, publishing, textiles, cosmetics, and health products. In this paper, we used and reported new methods for the purification, nanonization, and structural morphological investigations of As4S4 by using planetary ball mills process for nanonization of the compound. The product was characterized using X-ray powder diffraction analysis, Fourier transform infrared spectrometry spectra, and field emission scanning electron microscope (FESEM) imaging. We investigated the morphological properties of FESEM-imaged realgar nanoparticles by an image-processing technique that calculates fractal dimensions using values on a computer with MATLAB software. We applied the Statistical Package for the Social Sciences software for statistics data extracted from the FESEM image and obtained the statistics results of the fractal dimension and histogram plot for the FESEM image. Copyright © 2015 Amir Lashgari et al.Ítem Tuning the electronic, photophysical and charge transfer properties of small D-A molecules based on Thienopyrazine-terthienyls by changing the donor fragment: A DFT study(Sociedad Chilena de Quimica, 2017) Aicha, Youssef Ait; Bouzzine, Si Mohamed; Zair, Touriya; Bouachrine, Mohammed; Hamidi, Mohamed; Salgado-Morán, Guillermo; Tagle, R. Ramirez; Mendoza-Huizar, Luis H.Four acceptor-donor organic conjugated molecules based on thieno[3,4-b]pyrazine-terthienyls were analyzed in order to explore the effect of the donor substituent on their molecular structures, electronic and optical properties. Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD/DFT) calculations were carried out employing the B3LYP hybrid functional in combination with the 6-31G(d,p) basis set. The results suggests that the addition of electron-donating substituents to the conjugated molecules can diminish their energy gap value, which is beneficial to the photon harvesting. The lowest-lying absorption spectra of compounds substituted with electron donor groups exhibited a red-shift and a high oscillation factor compared with the unsubstituted molecule. Additionally, the ionization potential (IP), electron affinity (EA), reorganization energy (λ) and open-circuit voltage (Voc) of the molecules were evaluated. According to these values, the molecules show good photovoltaic properties, and efficient charge transfer for hole and electron and balanced charges.