Browsing by Author "Aliaga Miranda, Margarita Elly"
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- ItemA comparative study on the cucurbit[7]uril-based indicator displacement assay for methyl Viologen. A theoretical and experimental perspectivePavez Guerrero, Paulina; Fierro Huerta, Angelica Maria; Rojas Guerrero, Mabel Natalia; Garcia-Rio, Luis; Dinamarca-Villarroel, Luis; Fuentealba Patino, Denis Alberto; Droguett Muñoz, Kevin Arturo; Santos Blanco, José Guillermo; Aliaga Miranda, Margarita EllyOne colorimetric and one fluorescent-indicator displacement assay (IDA) were studied to assess their interaction with methyl viologen (MV), an herbicide commercially known as paraquat. The host–guest complexes formed by cucurbit[7]uril (CB[7]) and the 4-nitroaniline (NA) or Berberine (Be) dyes function as colorimetric- and fluorescent-IDA for MV, respectively. The CB[7]@NA and CB[7]@Be complexes were characterized by UV–vis, fluorescence spectroscopy, and dynamic simulations. Isothermal titration calorimetry (ITC) experiments and dynamic simulations were employed to obtain thermodynamic data for the formation of the 1:1 inclusion complexes. Finally, NA is proposed as a reference colorimetric dye for determining CB[7]-binding affinities using competitive host–guest titrations, and the fluorescent-IDA as the best assay proposed, as it exhibits a high binding constant, a good detection limit of 2.7 × 10−6 mol L-1, good linearity in the range from 4 × 10−6 mol L-1 to 3.5 × 10−5 mol L-1, in aqueous solution.
- ItemA selective fluorescent probe for the detection of mercury (II) in aqueous media and its applications in living cells(2012) Garcia-Beltran, Olimpo; Mena, Natalia; Berrios, Tania A.; Castro R., Enrique; Cassels, Bruce K.; Nuñez, Marco T.; Aliaga Miranda, Margarita Elly
- ItemA selective thioxothiazolidin-coumarin probe for Hg2+ based on its desulfurization reaction. Exploring its potential for live cell imaging(2020) Aliaga Miranda, Margarita Elly; Gazitúa López, Marcela Ivonne; Rojas-Bolaños, A; Fuentes-Estrada, M; Durango, D; García-Beltran, O
- ItemAminolysis and pyridinolysis of O-aryl S-(4-nitrophenyl) thiocarbonates in aqueous ethanol. Kinetics and mechanism(2008) Castro R., Enrique; Aliaga Miranda, Margarita Elly; Santos Blanco, José Guillermo
- ItemAnalytical Parameters of the Microplate-Based ORAC-Pyrogallol Red Assay(2011) Ortiz, Rocio; Antilén Lizana, Mónica; Speisky, Hernán; Aliaga Miranda, Margarita Elly; López Alarcón, Camilo Ignacio
- ItemApplication of a Microplate-Based ORAC-Pyrogallol Red Assay for the Estimation of Antioxidant Capacity: First Action 2012.03(2012) Ortiz, Rocio; Antilén Lizana, Mónica; Speisky, Hernán; Aliaga Miranda, Margarita Elly; López Alarcón, Camilo Ignacio; Baugh, Steve
- ItemAssessment of the redox cycling properties of nitrocompounds using a superoxide-dependent pyrogallol red bleaching assay(2012) López Alarcón, Camilo Ignacio; Speisky, Hernán; Aliaga Miranda, Margarita Elly; Lissi, E.; Rojas, M.; Faúndez Cáceres, Mario
- ItemCambios espectrales y reactividad de homólogos de azacumarina en sistemas supramoleculares basados en ciclodextrinas y cucurbiturilos(2021) Alcázar Jiménez, Jackson José; Aliaga Miranda, Margarita Elly; Santos Blanco, José Guillermo; Pontificia Universidad Católica de Chile. Facultad de QuímicaLas ciclodextrinas (CDs) y cucurbiturilos (CBs) son moléculas anfitrionas, relativamente solubles en agua con cavidades descritas como hidrofóbicas. Aunque la polaridad en la cavidad de las CDs y CBs es similar, sus diferencias estructurales y dimensionales han producido variaciones en su funcionalidad en términos de reactividad y selectividad. En este contexto, este trabajo de investigación tiene como objetivo general, evaluar los comportamientos espectrales y la reactividad frente a la reacción de hidrólisis para una serie de aza-cumarinas sustituidas en presencia y ausencia de CDs y CBs. Para ello, cinco homólogos de 7-(dialquilamino)aza-cumarina 3-sustituidas (DAAS) fueron sintetizados y caracterizados satisfactoriamente por RMN, ESI-HRMS e IR. Luego tales sustratos fueron estudiados espectroscópicamente en solución acuosa en ausencia y presencia de β-CD, DM-β-CD, γ-CD y CB7. Los resultados mostraron, que las propiedades espectrales de las DAAS sintetizadas y sus reactividades frente a la reacción de hidrólisis pueden ser afectadas según la naturaleza del macrociclo empleado, siendo el CB7 y la DM-β-CD los macrociclos más influyentes en los resultados cinéticos de este trabajo. Entre los resultados destacan: grandes efectos batocrómicos (4500cm-1) y desactivación total de la emisión de las DAAS, atribuido a la protonación del nitrógeno heterocíclico del sustrato tras su inclusión en CB7. También destaca un aumento de hasta 5,5 veces en el rendimiento cuántico de las DAAS en presencia de DM-β-CD. En términos de reactividad, el DM-β-CD y el CB7 produjeron efectos de inhibición significativos frente a la reacción de hidrólisis en medio ácido para el DAAS de tipo base de Schiff (DMSB), con diferentes constantes de asociación 3x103 y 2x105 M-1, respectivamente. Finalmente, para dilucidar el efecto de inhibición, un estudio cinético en imino-cumarinas (IC) fue llevado a cabo, de tal manera que, un modelo cinético general para la hidrólisis ácida de iminas, en presencia de CB7, fue propuesto.
- 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.
- ItemControlled keto-enol tautomerism of coumarin containing beta-ketodithioester by its encapsulation in cucurbit[7]uril(2017) Aliaga Miranda, Margarita Elly; García-Río, Luis; Numi, Ambar; Rodríguez, Alejandra; Arancibia-Opazo, Sandra; Fierro Huerta, Angélica; Cañete Molina, Álvaro
- ItemCoumarin-Based Fluorescent Probes for Dual Recognition of Copper(II) and Iron(III) Ions and Their Application in Bio-Imaging(2014) Martínez Ahumada, Natalia del Pilar; Pavez Guerrero, Paulina Isabel; Aliaga Miranda, Margarita Elly; García Beltrán, Olimpo; Cassels, Bruce K.; Pérez, Claudio; Mena, Natalia; Núñez, Marcos T.
- ItemCu(II)-disulfide complexes display simultaneous superoxide dismutase- and catalase-like activities(2013) Aliaga Miranda, Margarita Elly; Andrade Acuña, Daniela; López Alarcón, Camilo Ignacio; Sandoval Acuña, Cristián; Speisky, Hernán
- ItemCucurbit[7]uril limits the binding of coumarin bearing alkyl-acetoacetate with mercury and stimulates the desulphurisation reaction of its sulphur analog(2020) Aliaga Miranda, Margarita Elly; Pavez Guerrero, Paulina Isabel; Quintero Faúndez, Guillermo; Droguett Muñoz, Kevin; Cañete, Á.; Santos Blanco, José Guillermo
- ItemDetection of SO2 derivatives using a new chalco-coumarin derivative in cationic micellar media: application to real samples(2018) Gomez, Marisol; Aliaga Miranda, Margarita Elly; Arancibia Moya, Verónica; Moya, Alexis; Segura, Camilo; Nunez, Marco T.; Aguirre, Pabla; Nagles Vidal, Edgar Orlando; Garcia-Beltran, Olimpo
- ItemDetermination of molybdenum(VI) via adsorptive stripping voltammetry using an ex-situ bismuth screen-printed carbon electrode(2020) Rojas Romo, Carlos Roberto; Aliaga Miranda, Margarita Elly; Arancibia Moya, Verónica
- ItemDetermination of Pb(II) and Cd(II) via anodic stripping voltammetry using an in-situ bismuth film electrode : Increasing the sensitivity of the method by the presence of Alizarin Red S(2020) Rojas Romo, Carlos Roberto; Aliaga Miranda, Margarita Elly; Arancibia Moya, Verónica; Gómez, Miguel
- ItemDetermination of Se(IV) concentration via cathodic stripping voltammetry in the presence of Cu(II) ions and ammonium diethyl dithiophosphate(2019) Merino, Ignacio E.; Stegmann, Edgardo; Aliaga Miranda, Margarita Elly; Gomez, Marisol; Arancibia Moya, Verónica
- ItemDetermination of Sudan I in drinks containing Sunset yellow by adsorptive stripping voltammetry(2016) Gómez Arancibia, Marisol; Arancibia Moya, Verónica; Aliaga Miranda, Margarita Elly; Nuñez, C.; Rojas Romo, Carlos Roberto
- ItemDouble edge redox-implications for the interaction between endogenous thiols and copper ions: In vitro studies(2008) Carrasco-Pozo, Catalina; Aliaga Miranda, Margarita Elly; Olea-Azar, Claudio; Speisky, Hernán
- Item(E)-2-(Benzo[d]thiazol-2-yl)-3-heteroarylacrylonitriles as efficient Michael acceptors for cysteine : real application in biological imaging(2014) De La Torre, P.; García Beltrán, O.; Tiznado, W.; Mena, N.; Saavedra, L.; Cabrera, M.; Trilleras, J.; Pavez Guerrero, Paulina Isabel; Aliaga Miranda, Margarita Elly
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