Biscarboxy-Functionalized Imidazole and Palladium as Highly Active Catalytic System in Protic Solvents: Methanol and Water

The coupling reaction between aryl bromides and boron reagents is efficiently catalyzed by an in situ generated palladium complex obtained from palladium(II) acetate (0.1 mol%) and 1,3-bis(carboxymethyl)imidazole (0.2 mol%). The catalytic system is very active in protic solvents, especially in methanol. Biaryl derivatives have been prepared in good isolated yields (up to >99%), and additionally styrene and stilbene derivatives have also been prepared by means of this protocol.

Redes sociales para mayores y/o mayores en las redes sociales

La consolidación de la Web 2.0 y los medios sociales en nuestra sociedad coincide en el tiempo con el paulatino afianzamiento de un mercado emergente, el de las personas mayores. El objetivo de esta investigación es analizar, en el contexto de las redes sociales, cómo se gestiona la comunicación con el público maduro en España. Dos de los criterios que las empresas normalmente consideran cuando evalúan nuevos mercados son su peso económico y demográfico; en ambas áreas las personas mayores se han convertido en un grupo importante, convirtiéndose en uno de los mercados con mayor futuro del que además habría que destacar no sólo su tamaño y densidad, sino también su carácter heterogéneo, su variedad (Hudson, S., 2010; Westerhof et al., 2010; Imserso, 2009; Sudbury, L. y Simcock, P.,2009; Furlong, 2007; Kohlbacher y Herstatt, 2008: Thornhill y Martin, 2007). ¿Cumplen las redes sociales con las expectativas de los mayores, como público específico? Las redes sociales para mayores ¿son comunidades basadas en actitudes o conocimientos? (Matías Fernández, 2006) Los mayores, además de elegir redes y contenidos, ¿son internautas reales de redes sociales?, ¿son activos en la generación de contenidos hasta controlar la comunicación?... No existen precedentes y el trabajo persigue averiguar el papel de las personas mayores en las redes sociales específicas, así como el papel de las nuevas tecnologías en la comunicación de y con las personas mayores. Además, las conclusiones permitirán definir las hipótesis de estudios posteriores.

Methoxylation of α-pinene over mesoporous carbons and microporous carbons: A comparative study

A biomass derived carbon, a commercial microporous carbon and a xerogel mesoporous carbon catalysts were used in the study of α-pinene methoxilation reaction and the influence of textural and physical–chemical properties of the carbons was evaluated. Biomass carbon presented the higher activity, whereas the commercial one is the less active in the conditions studied. The main product of the reaction was α-terpinyl methyl ether and good values of selectivity were obtained over all the catalysts. A kinetic model was developed assuming that the α-pinene is consumed according to the parallel reaction network. The kinetic model presents high quality fittings to the experimental concentration profiles. These results show that it is possible to activate a waste residue using H3PO4 and convert it to high added value product such as acid catalyst.

Palladium(II) complexes with a phosphino-oxime ligand: synthesis, structure and applications to the catalytic rearrangement and dehydration of aldoximes

The treatment of [PdCl2(COD)] (COD = 1,5-cyclooctadiene) with 1 and 2 equivalents of 2-(diphenylphosphino)benzaldehyde oxime in dichloromethane at room temperature led to the selective formation of [PdCl2{κ2-(P,N)-2-Ph2PC6H4CH[double bond, length as m-dash]NOH}] (1) and [Pd{κ2-(P,N)-2-Ph2PC6H4CH[double bond, length as m-dash]NOH}2][Cl]2 (2), respectively, which represent the first examples of Pd(II) complexes containing a phosphino-oxime ligand. These compounds, whose structures were fully confirmed by X-ray diffraction methods, were active in the catalytic rearrangement of aldoximes. In particular, using 5 mol% complex 1, a large variety of aldoximes could be cleanly converted into the corresponding primary amides at 100 °C, employing water as solvent and without the assistance of any cocatalyst. Palladium nanoparticles are the active species in the rearrangement process. In addition, when the same reactions were performed employing acetonitrile as solvent, selective dehydration of the aldoximes to form the respective nitriles was observed. For comparative purposes, the catalytic behaviour of an oxime-derived palladacyclic complex has also been briefly evaluated.