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Gutierrez M.,University of Castilla - La Mancha | Sanchez F.,Institute Quimica Organica | Douhal A.,University of Castilla - La Mancha
Physical Chemistry Chemical Physics

We report on the spectra and dynamics of a Zr-naphthalene dicarboxylic acid (Zr-NDC) MOF in different diluted solvent suspensions and in a concentrated tetrahydrofuran (THF) one. In a diluted diethyl ether (DE) suspension, we observed intraparticle excimer formation between neighboring naphthalene organic linkers, leading to a red-shifted broad band in the emission spectrum and to a dynamics composed of three components τ1 = 650 ps, τ2 = 3.7 ns and τ3 = 13.9 ns, assigned to the excimer photoproduction, monomer and excimer lifetimes, respectively. Furthermore, both absorption and emission spectra show a blue shift in more polar solvents characterized by the solvent polarity function f(ε,n). We also observed changes in the excimer formation time (490-840 ps) probably due to a variation in the MOF structural fluctuation induced by solvent filling. The global fluorescence quantum yield of these suspensions is around 0.30 ± 0.05. At higher concentrations of the MOF particles, we observed the absorption and emission signals of aggregates having an intercrystal excimer formation in ∼5 ps in a THF suspension, ∼100 times shorter than that observed in a diluted one. Our results give the spectral and dynamical properties of a Zr-NDC MOF in solvent suspensions, opening the way to further studies of these kinds of MOFs interacting with fluorescent dyes for possible photonic applications. © the Owner Societies 2016. Source

Andres M.F.,CSIC - Institute of Agricultural Sciences | Gonzalez-Coloma A.,CSIC - Institute of Agricultural Sciences | Sanz J.,Institute Quimica Organica | Burillo J.,CSIC - Centro de Investigacion y Tecnologia Agroalimentaria | Sainz P.,CSIC - Institute of Agricultural Sciences
Phytochemistry Reviews

Plant parasitic nematodes are the most destructive group of plant pathogens worldwide and their control is extremely challenging. Plant Essential oils (EOs) and their constituents have a great potential in nematode control since they can be developed for use as nematicides themselves or can serve as model compounds for the development of derivatives with enhanced activity. This study reviews the plant EOs evaluated as potential nematicides and their toxic effects against pinewood nematode (Bursaphelenchus xylophilus) and root-knot nematodes (Meloidogyne spp.). Additionally, the nematicidal activity to M. javanica of several EOs from Spanish aromatic plants and their components is described. © 2012 Springer Science+Business Media Dordrecht. Source

Corma A.,Polytechnic University of Valencia | Juarez R.,Polytechnic University of Valencia | Boronat M.,Polytechnic University of Valencia | Sanchez F.,Institute Quimica Organica | And 2 more authors.
Chemical Communications

By a combination of kinetic and theoretical studies it is concluded that gold is intrinsically active to perform the Sonogashira coupling reaction between phenylacetylene and iodobenzene. The presence of Pd impurities is not mandatory for catalyst activity. © 2011 The Royal Society of Chemistry. Source

Leal J.A.,CSIC - Biological Research Center | Prieto A.,CSIC - Biological Research Center | Bernabe M.,Institute Quimica Organica | Hawksworth D.L.,Complutense University of Madrid | Hawksworth D.L.,Natural History Museum in London
FEMS Microbiology Reviews

The fungal wall contains a small proportion of alkali-extractable water-soluble heteromannans (F1SS). They are the glycidic moiety of glycoproteins that have important roles in the biology of fungi. A considerable number of these polysaccharides has been described, differing in composition or linkage types. Their structure is similar in all species of a well-delimited genus, and teleomorphs and their corresponding anamorphs. Therefore, these polysaccharides have been used as chemotaxonomic markers at the genus level. Here we review cases where they have been found to resolve relationships around the genus level, and assess their phylogenetic informativeness in the delineation of taxa at family and higher ranks in the ascomycetes by comparison with molecular trees. Generally, the correlation is extremely good, from the species to the class level, though there are some divergences. In particular, comparisons suggest that the concept of the Sordariomycetes may eventually require revision as more molecular data become available. An analysis of the different chemical structures of these polysaccharides can lead to the proposal and testing of phylogenetic hypotheses, in a parallel manner to those generated from molecular trees. These molecules serve as an independent character similar to morphological or molecular characters. © 2010 Federation of European Microbiological Societies. All rights reserved. Source

Natera J.E.,National University of Rio Cuarto | Massad W.A.,National University of Rio Cuarto | Amat-Guerri F.,Institute Quimica Organica | Garcia N.A.,National University of Rio Cuarto
Journal of Photochemistry and Photobiology A: Chemistry

The sensitized photopolymerization of 3,3′-diaminobenzidine tetrahydrochloride (DAB) to yield a localized electron-dense precipitate is the basis of a correlative imaging technique, in which fluorescence and transmission electron microscopies are applied to dye-labeled biological samples. In the present work, the eosin (Eo) sensitized photooxidation of DAB has been investigated, as a model system for understanding the complex photochemical mechanism of this imaging process. It was observed that the irradiation with visible light (515 nm) of aqueous solutions of DAB plus Eo triggers a fast photoreaction of DAB, a parallel consumption of dissolved oxygen, and the formation of an optically dense polymer. Time-resolved spectroscopic measurements as a function of solution composition were used to analyze the initial reactive steps of the photoreaction, which are mediated by the Eo lowest excited triplet state ( 3Eo*). From all these experiments it was concluded that singlet molecular oxygen [O 2( 1Δ g)], produced by the well-known 3Eo* plus O 2 reaction, and superoxide radical anion (O 2 •-) are the dominant reactant species in the photoprecipitation reaction. In contrast, in the absence of dissolved oxygen the rate of the photoreaction is only a 15% of the rate determined under aerobic conditions. © 2011 Elsevier B.V. All rights reserved. Source

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