Browsing by Author "Herrera Pisani, Bárbara Andrea"
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- ItemA Relation between Different Scales of Electrophilicity: Are the Scales Consistent Along a Chemical Reaction?(2012) Morell, Christophe; Herrera Pisani, Bárbara Andrea; Gutiérrez Oliva, Soledad; Ceron, Maria-Luisa; Grand, Andre; Toro Labbé, Alejandro
- 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
- ItemBasis Electronic Activity of Molecular Systems. A Theory of Bond Reactivity(2024) Benítez Olivares, Francisca Javiera; Gutiérrez Oliva, Soledad; Herrera Pisani, Bárbara Andrea; Toro Labbé, AlejandroIn this paper, we present a new finding, the basis electronic activity (BEA) of molecular systems; it corresponds to the significant, although nonreactive, vibrationally induced electronic activity that takes place in any molecular system. Although the molecule’s BEA is composed of an equal number of local contributions as the vibrational degrees of freedom, our results indicate that only stretching modes contribute to it. To account for this electronic activity, a new descriptor, the bond electronic flux (BEF), is introduced. The BEF combined with the force constant of the potential well hosting the electronic activity gives rise to the effective bond reactivity index (EBR), which turns out to be the first density functional theory-based descriptor that simultaneously accounts for structural and electronic effects. Besides quantifying the bond reactivity, EBR provides a basis to compare the reactivities of bonds inserted in different chemical environments and paves the way for the exertion of selective control to enhance or inhibit their reactivities. The new concepts formulated in this paper and the associated computational tools are illustrated with characterization of the BEA of a set of representative molecules. In all cases, the BEFs follow the same linear pattern, whose slopes indicate the intensity of the electronic activity and quantify the reactivity of chemical bonds.
- 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.
- 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.
- ItemCubane oligomers: A density functional theory study(2006) Herrera Pisani, Bárbara Andrea; kiwiTichauer, Miguel Germán; Toro Labbé, Alejandro
- ItemEffect of beryllium bonds on the keto-enol tautomerism of formamide derivatives : a subtle basicity-acidity balance(2016) Lamsabhi, A.; Vallejos, M.; Herrera Pisani, Bárbara Andrea; Mo, O.; Yañez, M.
- 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
- ItemElucidating the Catalytic Role of Mg(II) in the Intramolecular Proton Transfer Reaction in Thymine(2012) Vogt-Geisse, Stefan; Gutiérrez Oliva, Soledad; Herrera Pisani, Bárbara Andrea; Toro Labbé, Alejandro
- 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
- ItemInsights into the chemical meanings of the reaction electronic flux(2015) Morell, Christophe; Tognetti, Vincent; Bignon, Emmanuelle; Dumont, Elise; Hernandez Haro, Noemi; Herrera Pisani, Bárbara Andrea; Grand, André; Gutiérrez Oliva, Soledad; Joubert, Laurent; Toro Labbé, Alejandro; Chermette, Henry
- 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
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