Browsing by Author "Herrera Pisani, Bárbara Andrea"
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- ItemAn extension of the Marcus equation: the Marcus potential energy function(2018) Gutierrez-Oliva, Soledad; Herrera Pisani, Bárbara Andrea; Toro Labbé, Alejandro
- ItemApplying Sanderson rules to the formation reaction of hydrogen-bonded dimers(2012) Inostroza Rivera, Ricardo; Herrera Pisani, Bárbara Andrea; Toro Labbé, Alejandro
- ItemAtomic decomposition of conceptual DFT descriptors : application to proton transfer reactions(2015) Inostroza Rivera, Ricardo; Yahia Ouahmed, Meziane; Tognetti, Vincent; Joubert, Laurent; Herrera Pisani, Bárbara Andrea; Toro Labbé, Alejandro
- ItemCharacterization of the reactive conformations of protonated histamine through the reaction force analysis and the dual descriptor of chemical reactivity(2007) Correa Correa, José Vicente; Herrera Pisani, Bárbara Andrea; Toro Labbé, Alejandro
- ItemComplexation of AAPH (2,2′-azobis(2-methylpropionamidine) dihydrochloride) with cucurbit[7]uril enhances the yield of AAPH-derived radicals(2023) Forero Girón, Angie; Fuentealba Patiño, Denis Alberto; Mariño Ocampo, Nory Johana; Gutiérrez Oliva, Soledad; Herrera Pisani, Bárbara Andrea; Toro Labbé, Alejandro; Fuentes Lemus, Eduardo; Davies, Michael J.; Aliaga Miranda, Margarita Elly; López Alarcón, Camilo IgnacioAAPH (2,2′-azobis(2-methylpropionamidine) dihydrochloride), a water-soluble azo compound is widely employed to produce peroxyl radicals for chemical and biological studies. This compound is shown herein to form a stable inclusion complex with cucurbit[7]uril (CB7), a well-established supramolecular host. Competitive binding assays using berberine dye, isothermal titration calorimetry (ITC), and nuclear magnetic resonance (1H-NMR) experiments, provided evidence for the inclusion of AAPH inside the CB7 cavity with a binding constant of 2.5 ± 0.8 x 105 L mol-1 (determined by ITC). Computational analysis at B3LYP-D3BJ/6-311G(d,p) of the complex (AAPH@CB7) showed interactions of the positively-charged amino groups of AAPH with carbonyl functions at the CB7 entrances. Photolysis of AAPH@CB7 by illumination at 365 nm, gave a higher yield of carbon-centered radicals when compared to the absence of CB7, as evidenced by electron paramagnetic resonance spin trapping using α-phenyl-N-t-butylnitrone. Enhanced radical formation was corroborated by increased consumption of pyrogallol red, free Trp and Trp-containing peptides when these were exposed to AAPH@CB7 in the presence of light. The increased yield of radicals generated by AAPH@CB7 is believed to arise from a pull effect of CB7 portals on initial AAPH-derived carbon-centered radicals generated by photolysis. It is proposed that these radicals are exposed and released to the bulk solution and react with O2 to give peroxyl radicals. These results suggest that the AAPH@CB7 complex can be used to generate high yields of peroxyl radicals for their use in studying these species in material, environmental and biomedical sciences amongst others.
- ItemComputational study of the supramolecular complexation of azocompounds with cucurbit[7]uril: effects on the production and release of free radicals(Springer Science and Business Media Deutschland GmbH, 2024) Forero Girón, Angie; Gutiérrez Oliva, Soledad; López Alarcón, Camilo Ignacio; Herrera Pisani, Bárbara Andrea; Aliaga Miranda, Margarita EllyContext: An inclusion complex between 2,2′-azobis(2-methylpropionamidine) dihydrochloride (AAPH), a widely employed azocompound, and cucurbit[7]util (CB[7]), has shown an increased yield of radicals derived from the homolytic cleavage of the azo bond. Aimed to get insights about the formation of complexes and their effect on the yield of radicals production, complexes of CB[7] with seven azocompounds were studied by computational methods. Molecular electrostatic surfaces and structural analysis showed that the inclusion of symmetrical azocompounds inside of CB[7] depends mainly on the charge density and position of the functional groups at the main chain of the azoderivative. Analysis of non-covalent interactions and thermodynamic outcomes revealed that positively charged azocompounds with amidinium or imidazolium groups presented strong favorable interactions (multiple hydrogen bonds) with the oxygens of CB[7] portals. Additionally, carbon-centered radicals generated from the complexes (azocompounds@CB[7]) were corroborated using the electron localization function (ELF). Results evidenced that the strength of the interactions and the level of inclusion (partial or complete) between the azocompound and CB[7] determined the final orientation of the radicals (located out- or inside of the CB[7] cavity). Obtained results could be employed to design new supramolecular systems based on the properties of azocomplound@CB[7] complexes for new scientific or industrial applications. Methods: First-principles calculations at B3LYP-D3BJ/6-311g(d,p) level theory in the gas phase and in solvent (PCM, water) were performed in Gaussian 16 software package. The dispersion energy correction was included through the Grimme’s dispersion with Becke-Johnson damping D3(BJ). Thermodynamical data and the minimum character of all structures were obtained from vibrational frequency calculations. NBO, Multiwfn, Chemcraft, and NCIPLOT software were used to perform population analysis, analyze outcomes, visualize data, and display non-covalent interactions respectively.
- ItemConformational effects on glycine ionization energies and Dyson orbitals(2004) Herrera Pisani, Bárbara Andrea; Dolgounitcheva, O.; Zakrzewski, V.G.; Toro Labbé, Alejandro; Ortiz, J.V.
- ItemEfficacy of acetic acid and modified atmosphere packaging against Campylobacter Jejuni in poultry(2011) Gonzalez-Fandos, E.; Maya, N.; Herrera Pisani, Bárbara Andrea; Diaz-Gomez, J.
- ItemEfficacy of citric acid against Listeria monocytogenes attached to poultry skin during refrigerated storage(2009) Gonzalez-Fandos, Elena; Herrera Pisani, Bárbara Andrea; Maya, Naiara
- ItemEstudio teórico de carbenoides metálicos y sus reacciones de inserción en enlaces N-H Y O-H(2020) Durán Guajardo, Rocío Belén; Herrera Pisani, Bárbara Andrea; Toro Labbé, Alejandro; Pontificia Universidad Católica de Chile. Facultad de QuímicaDebido a los desafíos que presenta la construcción de enlaces C-X (X: heteroátomo), especialmente en la síntesis de productos de interés industrial, se han propuesto estrategias a esta problemática como la reacción de inserción de carbenoides metálicos en enlaces X-H. En el presente trabajo de tesis, se estudió a nivel teórico, el mecanismo de reacción de inserción del carbenoide de cobre en enlaces X-H (X: N, O), ya que esta reacción proporciona procesos directos y eficientes hacia la formación de enlaces carbono-X y, además, corresponde a un método atractivo, ya que la activación X-H inducida por el metal no interactúa directamente con éste, sino más bien, con el carbono electrofílico del carbenoide. Los resultados indicaron que la reacción ocurre mediante el acercamiento posterior del sustrato (anilina/fenol) siguiendo un mecanismo concertado, el cual presenta tres pasos importantes: (i) proceso sin barrera de energía llevando a un complejo reactante inicial, (ii) transferencia protónica del sustrato al carbenoide, que genera la salida del complejo de cobre (paso elemental) y (iii) ruptura de interacciones no covalentes entre el producto de inserción y el complejo de cobre. La inserción en el enlace O-H es favorecida tanto desde el punto de vista cinético como termodinámico con respecto al enlace N-H, donde la enantioselectividad de la inserción está dada por el ligando PhBOX mediante repulsiones estéricas, favoreciendo la formación del enantiómero R como producto de inserción. Para el paso elemental de la reacción, se utilizaron los modelos de fuerza de reacción (F(⇠)) y de activación y distorsión (ASM), encontrándose que la energía de activación para ambas reacciones es dominada por repulsiones estéricas entre el ligando y el sustrato utilizado. La fuerza de reacción indica que una gran contribución de la barrera energética en N-H es producto de la mayor contribución de W2, que impide el proceso de inserción. Adicionalmente, un estudio del efecto del sustituyente fue hecho para la reacción en el enlace O-H, modificando la estructura del carbenoide y del sustrato fenólico, de modo que, se favorece la cinética cuando se utilizan sustituyentes atractores de electrones en la posición orto o para al OH del fenol.
- ItemExtending the halogen-bonded supramolecular synthon concept to 1,3,4-oxadiazole derivatives(2016) Hidalgo, Paulina; Leal, Sergio; Jimenez, Claudio A.; Vohringer Martínez, Esteban; Herrera Pisani, Bárbara Andrea; Pasan, Jorge; Ruiz Pérez, Catalina; Bruce, Duncan D.
- ItemFormation of Copper Nanoparticles Supported onto Inclusion Compounds of alpha-cyclodextrin: A New Route to Obtain Copper Nanoparticles(2010) Silva, Nataly; Moris, Silvana; Herrera Pisani, Bárbara Andrea; Diaz, Maximiliano; Kogan, Marcelo J.; Barrientos, Lorena; Yutronic, Nicolas; Jara, Paul
- ItemInclusion compounds of alpha-cyclodextrin with alkylthiols(2008) Jara, Paul; Barrientos, Lorena; Herrera Pisani, Bárbara Andrea; Sobrados, Isabel
- ItemInfluence of the monoclinic and tetragonal zirconia phases on the water gas shift reaction. A theoretical study(2013) Cerón, M.; Herrera Pisani, Bárbara Andrea; Araya, P.; Gracia, F.; Toro Labbé, Alejandro
- ItemMechanistic Insight toward Understanding the Role of Charge in Thiourea Organocatalysis(2020) Smajlagic, I; Guest, M; Durán Guajardo, Rocío Belén; Herrera Pisani, Bárbara Andrea; Dudding, T
- ItemOn the mechanism of hydrogen transfer in the HSCH(O) reversible arrow (S)CHOH and HSNO reversible arrow SNOH reactions(2005) Gutiérrez Oliva, Soledad; Herrera Pisani, Bárbara Andrea; Toro Labbé, Alejandro; Chermette, Henry
- ItemPhenolysis and benzenethiolysis reactions of carbonyl and thiocarbonyl compounds from the perspective of the HSAB principle(2007) Pavez Guerrero, Paulina Isabel; Herrera Pisani, Bárbara Andrea; Castro R., Enrique; Santos Blanco, José Guillermo; Toro Labbé, Alejandro
- ItemReaction electronic flux and its role in DNA intramolecular proton transfers(2016) Durán Guajardo, Rocío Belén; Vöhringer Martínez, Esteban; Toro Labbé, Alejandro; Herrera Pisani, Bárbara Andrea
- ItemReaction Electronic Flux Perspective on the Mechanism of the Zimmerman Di-π-methane Rearrangement(2018) Matute, Ricardo A.; Villegas, Nery Andrés; Herrera Pisani, Bárbara Andrea; Gutiérrez Oliva, Soledad; Toro Labbé, Alejandro; Pérez, Patricia; Chamorro, Eduardo; Cortés Arriagada, Diego
- ItemReaction mechanism of li and mg carbenoid cyclopropanations : metal-pi and sigma interactions(2019) Villablanca, D.; Durán Guajardo, Rocío Belén; Lamsabhi, A.; Herrera Pisani, Bárbara Andrea