Synthesis and Complexation of Polytopic Adamantane-Based Probes

The 9th International Electronic Conference on Synthetic Organic Chemistry session Supramolecular ChemistryThe authors thank the Ministerio de Ciencia y Tecnología (Project MAT2001-2911) and Xunta de Galicia (PGIDIT02PXIC26202PN) for financial support. V. H. Soto thanks AECI (Beca Mutis)/University of Costa Rica for a research scholarshi

Synthesis, characterization and self aggregation of a new neo-pentylamide cholic derivative (Na-n-penC)

The 10th International Electronic Conference on Synthetic Organic Chemistry session Supramolecular ChemistryThe self-aggregation in aqueous solution of a new neo-pentyl amide of the 3-β-amino derivative of cholic acid (Na-n-penC) has been investigated in aqueous solution by surface tension and steady state-fluorescence spectroscopy of pyrene (used as a probe). The nature of the agregates was determined by transmission electron microscopy (TEM) revealing that vesicles are formed. The structure of the compound in the solid state was resolved by X-ray spectroscopy. The synthesis of the compound is also give

Caracterização estrutural de vesículas modificadas com quitosana

Vesículas a base de L-α-fosfatidilcolina (PC) y mezclas de PC/fosfogliceroles fueron caracterizadas por medio de dispersión de luz dinámica (DLS), microscopía electrónica de barrido-criogénico (Cryo-SEM) y calorimetría de titulación isotérmica (ITC). La incorporación de fosfogliceroles en la formulación de vesículas a base PC disminuyó el tamaño y la polidispersidad de las partículas, debido a un mayor empaquetamiento de las cadenas alifáticas por medio de interacciones de van der Waals. Además, resultó en una disminución significativa de la carga superficial de -75 mV comparada con el potencial Z (ξ) de las vesículas a base de PC. Ambos sistemas fueron modificados usando un polielectrolito catiónico (quitosano) de un peso molecular de 865 kDa y con un grado de desacetilación de 77 %. La naturaleza aniónica de la vesícula fosfolipídica resultó en una efectiva interacción con el polielectrolito catiónico mediante fuerzas del tipo electrostática, la cual fue determinada por medio de ITC. Los resultados fueron complementados mediante la determinación de potencial Z de los sistemas modificados, lo cual demostró que no es necesaria una inversión completa de la carga inicial de la superficie de la vesícula para asegurar el recubrimiento de esta. La adición de concentraciones de quitosano mayores a 0,1 mg/mL condujo a la agregación de las vesículas, lo cual fue demostrado mediante Cryo-SEM y DLS. Este efecto fue más significativo para el sistema basado en dimiristoilfosfoglicerol sal de sodio y quitosano, debido a la fuerte atracción electrostática.L-α-phosphatidylcholine (PC) and PC/phosphoglycerol based-vesicles were characterized by Dynamic Light Scattering (DLS), Cryo-Scanning Electron Microscopy (Cryo-SEM), and Isotermal Titration Calorimetry (ITC). The incorporation of phosphoglycerol into the PC vesicles decreased the size and the polydispersity of the particles, due to an increase of the packing of the aliphatic chains in the layer. This phenomenon has been interpreted in terms of strong van der Waals interactions. The addition of phosphoglycerols resulted in a reduction in zeta potential (ξ) to values of -75 mV, compared to PC based-vesicles. Both systems were modified by using a high molecular weight chitosan (865 kDa) with a degree of deacetylation of 77%. Strong electrostatic interactions between the cationic polyelectrolyte and the vesicles were determined by ITC experiments. The results were reinforced by means of Z potential analysis. It has been demonstrated that a complete inverse of the vesicle surface charge is not required to perform a complete coating of the phospholipid particles. The addition of concentration of chitosan above 0,1 mg/mL induced vesicles aggregation. Aggregated vesicle-polymer structures were visualized by Cryo-SEM and measured by DLS. This behavior was more significant for the PC/DMPG-Na-/chitosan system.Vesículas a base de L-α-fosfatidilcolina (PC) e mesclas de PC/fosfogliceróis foram caracterizadas por meio de dispersão de luz dinâmica (DLS), microscopia eletrônica de varredura-criogênico (Cryo-SEM) e calorimetria de titulação isotérmica (ITC). A incorporação de fosfogliceróis na formulação de vesículas a base de PC diminuiu o tamanho e a polidispersão das partículas, devido a um maior empacotamento das cadeias alifáticas por meio de interações de van der Waals. Além disso, resultou em uma diminuição significativa da carga superficial de -75 mV comparada com o potencial Z (ξ) das vesículas a base de PC. Ambos os sistemas foram modificados usando um polieletrólito catiônico (quitosana) de um peso molecular de 865 kDa e com um grau de desacetilação de 77 %. A natureza aniônica da vesícula fosfolipídica resultou em uma interação efetiva com o polieletrólito catiônico através de forças do tipo eletrostática, que foi determinada por meio de ITC. Os resultados foram complementados por meio da determinação de potencial Z dos sistemas modificados, o qual demostrou não ser necessária uma inversão completa da carga inicial da superfície da vesícula para assegurar o recobrimento desta. A adição de concentrações de quitosana maiores a 0,1 mg/mL conduziu à agregação das vesículas, o qual foi demostrado mediante Cryo-SEM e DLS. Este efeito foi mais significativo para o sistema baseado em dimiristoil fosfoglicerol sal de sódio e quitosana, devido à forte atração eletrostática.Ministerio de Ciencia y Tecnología/[Materiales inteligentes 023930]/MICIT/Costa RicaConsejo Nacional para Investigaciones Científicas y Tecnológicas/[Materiales inteligentes 023930]/CONICIT/Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Químic

Highly Hydrophilic and Lipophilic Derivatives of Bile Salts

Lipophilicity of 15 derivatives of sodium cholate, defined by the octan-1-ol/water partition coefficient (log P), has been theoretically determined by the Virtual log P method. These derivatives bear highly hydrophobic or highly hydrophilic substituents at the C3 position of the steroid nucleus, being linked to it through an amide bond. The difference between the maximum value of log P and the minimum one is enlarged to 3.5. The partition coefficient and the critical micelle concentration (cmc) are tightly related by a double-logarithm relationship (VirtuallogP=−(1.00±0.09)log(cmcmM)+(2.79±0.09)), meaning that the Gibbs free energies for the transfer of a bile anion from water to either a micelle or to octan-1-ol differ by a constant. The equation also means that cmc can be used as a measurement of lipophilicity. The demicellization of the aggregates formed by three derivatives of sodium cholate bearing bulky hydrophobic substituents has been studied by surface tension and isothermal titration calorimetry. Aggregation numbers, enthalpies, free energies, entropies, and heat capacities, ΔCP,demic, were obtained. ΔCP,demic, being positive, means that the interior of the aggregates is hydrophobicThis work was funded by the Ministerio de Ciencia y Tecnología, Spain (Project MAT2017-86109P)S

Essential oil of Lepechinia schiedeana (Lamiaceae) from Costa Rica

The composition of the essentiaí oil isolated by steam distillation from aerial parts of the Costa Rican herb Lepechinia schiedeana (Schlecht) Vatke (Lamiaceae) collected in El Empalme, Costa Rica, was determined by capillary gas chromatography (GC) and coupled gas chromatography-mass spectrometry (GCMS) analyses. Fifty-one components were identified corresponding ca. 93% of the oi!. The major components were -pinene (26.6%), cis -pinocamphone (25.1 %), &-3-carene (6.1 %), trans -pinocamphone (4.0%), camphor (3.8%) andSe estudiaron los constituyentes del aceite esencial de las partes aéreas de Lepechinia schiedeana (Lamiaceae) mediante el uso de cromatografía de. gases (GC) y cromatogr¡¡fía de gases acoplada a espectrometría ¡:le masas (GC-MS). Se éaraiterizaron 51 compuestos (qjle representan ca. del 93% del aceite) . El aceite se caracteriza por la presencia de gran cantidad de hidrocarbUros monoteq>énicos (45.9%) Y de monoterpefios oxigelÍJidos (39.7%). Los componentes mayoritarios fuero

(1S,3R)-N-{(3S,10S,12S,13R,17R)-12-Hydroxy-17- [(R)-5-hydroxypentan-2-yl]-10,13-dimethylhexa- decahydro-1H-cyclopenta[a]phenanthren-3-yl}- adamantane-1-carboxamide 0.25-hydrate

The title compound, C 35H 57 NO 3 0.25H 2O, was synthesized from deoxycholic acid followed by a protection, a Mitsonobu substitution, a Staudinger reduction, formation of an amide and final reduction in the lateral chain. The compound crystallizes in the P1 space group with four steroid molecules and one water molecule in the triclinic cell unit. The crystal structure features O—H O hydrogen bonding. The crystal studied was refined as a non-merohedral twinUniversidad de Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Químic

Caracterización estructural de vesículas modificadas con quitosano

L-α-phosphatidylcholine (PC) and PC/phosphoglycerol based-vesicles were characterized by means of Dynamic Light Scattering (DLS), Cryo-Scanning Electron Microscopy (Cryo-SEM), and Isotermal Titration calorimetry (ITC). The incorporation of phosphoglycerol into the PC vesicles decreased the size and the polydispersity of the particles, due to an increase of the packing of the aliphatic chains in the palisade layer. This phenomenon has been interpreted in terms of strong van der Waal interactions.  The addition of phosphoglycerols resulted in a reduction in zeta potential (ξ) to values of -75 mV, compared to PC based-vesicles. Both systems were modified by using a high molecular weight chitosan (865 kDa) with a degree of deacetylation of 77%. Strong electrostatic interactions between the cationic polyelectrolyte and the vesicles were determined by ITC experiments. The results were reinforced by means of Z potential analysis.  It has been demonstrated that a complete inverse of the vesicle surface charge is not required to perform a complete coating of the phospholipid particles. The addition of concentration of chitosan above 0,1 mg/mL induced vesicles aggregation. Aggregated vesicle-polymer structures were visualized by Cryo-SEM and measured by DLS. This behavior was more significant for the PC/DMPG-Na-/chitosan system.Vesículas a base de L-α-fosfatidilcolina (PC) y mezclas de PC/fosfogliceroles fueron caracterizadas por medio de dispersión de luz dinámica (DLS), microscopía electrónica de barrido-criogénico (Cryo-SEM) y calorimetría de titulación isotérmica (ITC). La incorporación de fosfogliceroles en la formulación de vesículas a base PC disminuyó el  tamaño y la polidispersidad de las partículas, debido a un mayor empaquetamiento de las cadenas alifáticas por medio de interacciones de van der Waals. Además, resultó en una disminución significativa de la carga superficial de -75 mV comparada con el potencial Z (ξ) de las vesículas a base de PC. Ambos sistemas fueron modificados usando un polielectrolito catiónico (quitosano) de un peso molecular de 865 kDa y con un grado de desacetilación de 77 %.  La naturaleza aniónica de la vesícula fosfolipídica resultó en una efectiva interacción con el polielectrolito catiónico mediante fuerzas del tipo electrostática, la cual fue determinada por medio de ITC. Los resultados fueron complementados mediante la determinación de potencial Z de los sistemas modificados, lo cual demostró que no es necesaria una inversión completa de la carga inicial de la superficie de la vesícula para asegurar el recubrimiento de esta. La adición de concentraciones de quitosano mayores a 0,1 mg/mL condujo a la agregación de las vesículas, lo cual fue demostrado mediante Cryo-SEM y DLS. Este efecto fue más significativo para el sistema basado en dimiristoilfosfoglicerol sal de sodio y quitosano, debido a la fuerte atracción electrostática.

Co-adsorbing effect of bile acids containing bulky amide groups at 3β-position on the photovoltaic performance in dye-sensitized solar cells

Co-adsorbing molecules attain certain control in the surrounding of the dyes leading to enhanced efficiencies mainly by affecting the recombination of the photogenerated electrons and aggregation of dyes. Bile acids such as deoxycholic acid (DOA) and chenodeoxycholic acid (CDOA) yield competitive photovoltaic parameters. We harness the steroid backbone of bile acids to chemically modified it at its R3 position attaching sterically demanding amide groups rather than typically terminal hydroxyl groups (3β-position) as in DOA and CDOA. All possible resultant effects on the performance in complete DSSCs were studied by current density-voltage curves (e.g., percentage of efficiency, %η; open-circuit voltage, Voc; short-circuit photocurrent, Jsc; and fill factor, FF), incident photon-to-current conversion efficiency (IPCE), and a set of interfacial data by electrochemical impedance spectroscopy (EIS). Our co-adsorbates stand out by enhancing the conversion efficiencies, being in some cases competitive with photovoltaic parameters of DOA and CDOA.Universidad de Costa Rica/[804-B2-A01]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Electroquímica y Energía Química (CELEQ)UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Químic

catena-Poly[[[diaquabis[1,2-bis(pyridin-4-yl)diazene]copper(II)]-μ-1,2-bis(pyridin-4-yl)diazene] bis(perchlorate)] bis(perchlorate)

In the title compound, {[Cu(C10H8N4)3(H2O)2](ClO4)2}n, the coordination environment of the cationic CuII atom is distorted octahedral, formed by pairs of symmetry-equivalent 1,2-bis(pyridin-4-yl)diazene ligands, bridging 1,2-bis(pyridin-4-yl)diazene ligands and two non-equivalent water molecules. The 1,2-bis(pyridin-4-yl)diazene molecules form polymeric chains parallel to [-101] via azo bonds which are situated about inversion centres. Since the CuII atom is situated on a twofold rotation axis, the monomeric unit has point symmetry 2. The perchlorate anions are disordered in a 0.536 (9):0.464 (9) ratio and are acceptors of water H atoms in medium–strong O—H...O hydrogen bonds with graph set R44(12). The water molecules, which are coordinated to the CuII atom and are hydrogen-bonded to the perchlorate anions, form columns parallel to [010]. A π–π interaction [centroid–centroid distance = 3.913 (2) Å] occurs between pyridine rings, and weak C—H...O interactions also occur

Síntesis de la feromona sexual de la polilla de la papa, Scrobipalpopsis Solanivora

Se sintetizó el acetato (E) -3- dodecenilo, atrayente sexual de la polilla de la papa (Scrobipalpopsis solanivora), utilizando dos procedimientos: una ruta acetilénica y mediante la condensación de Knoevenagel.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de QuímicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones en Productos Naturales (CIPRONA