Search results for "Crista"
showing 10 items of 180 documents
Hyperspectral near-field imaging : development and applications to nanophotonics devices
2013
The scanning near-field optical microscopy (SNOM) is used to analyze optical phenomena at the sub-wavelength scale such as light localization and propagation in photonic crystals or plasmonic devices. In any case, SNOM experiments rely on the positioning of a local probe in the optical near field of a given structure and on the detection of the surrounding evanescent waves. Depending on the nature of the probe or on the optical detection method, the detected physical properties are the spatial distributions of the amplitude and phase or the intensity of the electric and magnetic components of the probed field. We present here the implementation of an innovative hyperspectral near-field imag…
Coordination Chemistry of a Bis(Tetrazine) Tweezer: A Case of Host-Guest Behavior with Silver Salts
2021
The carbon-carbon cross-coupling of phenyl s-tetrazine (Tz) units at their ortho-phenyl positions allows the formation of constrained bis(tetrazines) with original tweezer structures. In these compounds, the face-to-face positioning of the central tetrazine cores is reinforced by π-stacking of the electron-poor nitrogen-containing heteroaromatic moieties. The resulting tetra-aromatic structure can be used as a weak coordinating ligand with cationic silver. This coordination generates a set of bis(tetrazine)-silver(I) coordination complexes tolerating a large variety of counter anions of various geometries, namely, PF6−, BF4−, SbF6−, ClO4−, NTf2−, and OTf−. These compounds were characterized…
Aproximaciones moleculares al estudio de las interacciones de rotavirus y norovirus con el huésped
2020
Los norovirus humanos son los principales agentes etiológicos de gastroenteritis aguda en todo el mundo. Aunque los norovirus son muy diversos (se han detectado más de 30 genotipos en humanos), durante los últimos 40 años la mayoría de los brotes y epidemias han sido causados por cepas del genotipo GII.4, lo que plantea interrogantes sobre su persistencia en la población. Entre otras posibles explicaciones, se considera que la evasión inmunológica es la principal causa de su éxito. Para estudiar en detalle el reconocimiento y la evasión de anticuerpos, analizamos un epítopo conformacional reconocido por un anticuerpo monoclonal (3C3G3) mediante mutagénesis dirigida y resonancia superficial …
Características texturales y microestructurales de un grupo seleccionado de arcillas especiales
2017
El objetivo de la presente tesis es la caracterización textural y microestructural de minerales de la arcilla de los grupos de la caolinita y de las esmectitas, presentes en materias primas de alto interés tecnológico e industrial como son los caolines y bentonitas.Se estudiaron las relaciones entre las características composicionales, texturales, microestructurales de los materiales seleccionados, y de sus suspensiones acuosas, la estabilidad de las mismas y su aprovechamiento mediante fraccionamiento mecánico. Para ello se aplicaron distintos métodos de análisis microestructural junto con técnicas de caracterización complementarias a los materiales seleccionados. En el caso de las fábrica…
SPATIAL DISTRIBUTION OF DENDROPOMA CRISTATUM (MOLLUSCA, GASTROPODA) ADULT BIOMASS ON A VERMETID REEF
2023
A spatial characterization of Dendropoma cristatum biomass was carried out on a Vermetid reef in north-western Sicily. Biomass distribution of adult specimens is not homogenous in the different areas of the reef, with an increasing trend from the inner edge to the outer edge, while the central pool supports intermediate values of vermetid biomass. Considering the entire reef area, the cuvette has the highest Dendropoma biomasses of the bioconstruction, even if the highest surface-biomass ratio is found in the outer edege.
High oxidation state aqueous organometallics. Formation and structure of an oxo-centred Cp*MoV trinuclear cation by chemical reduction of Cp*2Mo2O5
2002
International audience; Reduction of Cp*2Mo2O5 by zinc/CF3CO2H in MeOH–H2O yields a salt which is composed of [Cp*3Mo3O4(O2CCF3)3]+ and [Zn2(O2CCF3)6]2− ions after crystallisation from THF–Et2O.
Bromide hydrogen oxalate salts with the diprotonated 1,4-diazabicyclo[2.2.2]octane counterion
2020
Abstract Two new salts composed of the diprotonated 1,4-diazabicyclo[2.2.2]octane (DABCO) molecule as the cations and bromide and hydrogen oxalate as the anions have been isolated and structurally characterized by X-ray diffraction analysis. The salt [DABCOH2]{[HC2O4][Br]} (1) crystallizes in the orthorhombic system, space group P212121 with a = 9.0809(7), b = 9.5156(7), c = 12.3558(9) Å, V = 1067.67(14) Å3 and Z = 4. The salt [DABCOH2]2{[HC2O4][Br]3}·H2O (2) crystallizes in the orthorhombic system, space group Pnma with a = 26.6554(17), b = 7.3711(4), c = 10.7421(7) Å, V = 2110.6(2) Å3 and Z = 4. The compounds were prepared from ethanolic solutions of [DABCOH2][HC2O4]2 (L 1 ) and ZnBr2 in …
Interpenetrated Luminescent Metal-Organic Frameworks based on 1H-Indazole-5-carboxylic Acid
2020
Herein we report the formation and characterization of two novel Zn-based multifunctional metal-organic frameworks (MOFs) based on 1H-indazole-5-carboxylic acid and bipyridine-like linkers, synthesized by soft solvothermal routes. These materials possess isoreticular 2-fold interpenetrated three-dimensional structures that afford a flexible character and allow porosity modulation of the MOFs as confirmed by CO2 sorption measurements. Apart from this attractive structural feature, the MOFs exhibit fascinating luminescent properties involving both luminescence thermometry and long-lasting phosphorescence.
Synthesis of a rod-based porous coordination polymer from a nucleotide as a sequential chiral inductor
2021
We report the two-step synthesis of a novel chiral rod-based porous coordination polymer (PCP). The chemical approach consists of the use of a previously prepared bis(ethylenediamine) copper monomer [Cu(en)]2(NO3)2 [where en = ethylenediamine] reacting with the cytidine 5′-monophosphate (CMP) nucleotide. The bis(ethylenediamine) copper compound—stabilized by axial coordination of nitrate counter-anions—reacts in the presence of sodium salt of CMP to yield right-handed copper(II) chains of P helicity with formula [Cu2(en)2(CMP)2]·5H2O (1). The axial coordination of the CMP2- ligands through the N3 and O2 sites (free nitrogen and carbonyl groups) of the cytosine nucleobase and oxygen atoms of…
Functionalization of Bambusurils by a Thiol-Ene Click Reaction and a Facile Method for the Preparation of Anion-Free Bambus[6]urils
2018
Sulfide-functionalized bambus[4]urils ((RS)8 BU[4]) and bambus[6]urils ((RS)12 BU[6]) were synthesized through thiol-ene click coupling reactions (TEC) of allylbambus[n]urils. Thiosugars were grafted to BU[4] and BU[6]. Synthesis of BU[6] derivatives always requires the use of a template anion (iodide, chloride, or bromide), which is enclosed in the cavity of BU[6]. We show that this anion influences the reactivity of bambus[6]urils. An encapsulated iodide makes allyl functions of allyl12 BU[6] less reactive towards TEC and hydrogenation reactions in comparison to the corresponding chloride or bromide inclusion complexes. This is critical for the chemical reactivity of BU[6] and even more t…