Browsing by Author "Santos Blanco, José Guillermo"
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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 theoretical study on the relationship between nucleophilicity and ionization potentials in solution phase(2003) Contreras, R.; Andres, J.; Safont, V.S.; Campodónico Galdames, Paola Rossana; Santos Blanco, José Guillermo
- ItemAcetylated starch and inulin as encapsulating agents of gallic acid and their release behaviour in a hydrophilic system(2012) Robert Canales, Paz Soledad; Garcia, Paula; Reyes, Natalia; Chavez, Jorge; Santos Blanco, José Guillermo
- ItemActive Centers and Polymeric Effect in Poly(N-vinyl-2-pyrrolidone)-Monoalkyl Xanthate Systems(1994) Gargallo Gómez, Ligia Teresita; Pérez-Cotapos Larraín, Eduardo; Santos Blanco, José Guillermo; Radić Foschino, Deodato D.
- ItemAlpha-tocopherol microspheres with cross-linked and acetylated inulin and their release profile in a hydrophilic model(2013) García, Paula; Vega, Juan; Jiménez, Paula; Santos Blanco, José Guillermo; Robert, PazAlpha-tocopherol (AT) was encapsulated with native (NIn), acetylated (AIn) or cross-linked (CIn) inulin (two degrees each) by spray-drying. A face central composite experimental design for each system (AT–NIn, AT–AIn1, AT–AIn2, AT–CIn1, and AT–CIn2) was evaluated to determine the influence of inlet air temperature and AT/coating material ratio on the AT encapsulation percentage (EP). The AT microspheres obtained under optimal conditions were characterized determining the AT EP, morphology and their release profile in a hydrophilic system. The AT encapsulating percentage reached values above 86% in all the systems studied. The acetylation and cross-linking of inulin improved slight but significantly the AT encapsulating percentage respect to native inulin. The release profiles showed biphasic behavior, being the first and second zone attributed to uncovered and encapsulated AT, respectively. The AT release was <15% (0–540 min) from all AT-inulin microparticles, corresponding mainly to superficial AT release, following Higuchi model consistent with a diffusional mechanism. AT release rate constant from AT–NIn microspheres was significantly lower than those of AT–AIn and AT–CIn. The AT release pattern suggest that the microparticles could be applied in the design of functional foods, preserving the nutritional role of AT.
- 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
- ItemAnilinolysis of Reactive Aryl 2,4-Dinitrophenyl Carbonates: Kinetics and Mechanism(2011) Castro R., Enrique; Domecq, Claudia; Santos Blanco, José Guillermo
- 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.
- ItemConcerted aminolysis of diaryl carbonates: Kinetic sensitivity on the basicity of the nucleophile, nonleaving group, and nucleofuge(2012) Castro R., Enrique; Cubillos Pino, María Audomira; Iglesias, Rocio; Santos Blanco, José Guillermo
- ItemCONCERTED MECHANISM OF THE AMINOLYSIS OF 2,4,6-TRINITROPHENYL O-ETHYL DITHIOCARBONATE IN AQUEOUS-ETHANOL(1994) Castro R., Enrique; Cubillos Pino, María Audomira; Munoz, G.; Santos Blanco, José Guillermo
- ItemCONCERTED MECHANISM OF THE AMINOLYSIS OF O-ETHYL S-(2,4-DINITROPHENYL) THIOCARBONATE(1991) Castro R., Enrique; Ibáñez Walker, Fernando; Salas, M.; Santos Blanco, José Guillermo
- ItemConcerted mechanism of the reactions of 2,4-dinitrophenyl 4-cyanobenzoate with secondary alicyclic amines in aqueous ethanol(1998) Castro R., Enrique; Hormazábal Hidalgo, Andrea Soledad; Santos Blanco, José Guillermo
- ItemCONCERTED MECHANISM OF THE REACTIONS OF SECONDARY ALICYCLIC AMINES WITH O-ETHYL S-(2,4,6-TRINITROPHENYL) THIOCARBONATE(1994) Castro R., Enrique; Salas, M.; Santos Blanco, José Guillermo
- ItemConcerted mechanisms of the reactions of 2,4,6-trinitrophenyl methyl carbonate and 2,4,6-trinitrophenyl acetate with secondary alicyclic amines(2001) Castro R., Enrique; Cubillos Pino, María Audomira; Santos Blanco, José Guillermo
- ItemConcerted mechanisms of the reactions of ethyl S-aryl thiocarbonates with substituted phenoxide ions(1999) Castro R., Enrique; Pavez Guerrero, Paulina Isabel; Santos Blanco, José Guillermo
- ItemConcerted mechanisms of the reactions of methyl aryl carbonates with substituted phenoxide ions(2001) Castro R., Enrique; Pavez Guerrero, Paulina Isabel; Santos Blanco, José Guillermo
- ItemConcerted mechanisms of the reactions of phenyl and 4-nitrophenyl chlorothionoformates with substituted phenoxide ions(1998) Castro R., Enrique; Cubillos Pino, María Audomira; Santos Blanco, José Guillermo
- ItemConcerted Pyridinolysis of Aryl 2,4,6-Trinitrophenyl Carbonates(2009) Castro R., Enrique; Ramos, Mariela; Santos Blanco, José Guillermo
- 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