Reactive Palladium Carbenes: Migratory Insertion and Other Carbene-Hydrocarbyl Coupling Reactions on Well-Defined Systems

Producción CientíficaPalladium complexes with carbene ligands are among the best known and more extensively used catalysts. Those carbenes are usually NHC or N,N-disubstituted derivatives and their use relies on the robust nature of the carbene ligands and their role as auxiliary ligands that modify the metal's elec- tronic and steric features. In contrast, there are other types of carbenes that, when coordinated to palladium, lead to transfor- mations in which the carbene fragment is involved. In the last decade, palladium-catalyzed reactions have been extended to the use of carbene precursors that can be functionalized with the formation of several C–C bonds in one reaction step. Plausi- ble mechanisms have been proposed where a carbene–hydro- carbyl coupling occurs in the palladium coordination sphere. This microreview aims to collect and discuss the examples of organometallic reactions in well-characterized palladium com- plexes where the carbene is one of the fragments involved in C–C bond formation. These examples are key in understanding and supporting the mechanisms proposed for the Pd-catalyzed of C–C coupling reactions of carbenes.MINECO (SGPI, grant CTQ2016-80913-P)Junta de Castilla y León (grants VA062G18 and VA051P17

Evaluation of magnetic terms in Cu4O4 cubane-like systems from selected configuration interaction calculations: A case study of polynuclear transition-metal systems

We present the evaluation of magnetic terms in a Cu4O4 cubane-like system from truncated CI calculations, as a case study of polynuclear transition-metal complexes. We employ a new excitation selected configuration interaction (EXSCI) method based on the use of local orbitals. Taking advantage of the locality and then of the fact that the interactions vanish when the distance is large, the dimension of the CI is largely reduced. To the best of our knowledge these CI calculations are the largest one performed for polynuclear transition metal systems so far. The results show the presence of two leading ferromagnetic interactions between bridged Cu ions. Also the interactions between the unbridged Cu ions are ferromagnetic, but very weak, in contrast to the experimental data. The nature and amplitude of all the computed interactions are consistent with the relative orientation of the magnetic orbitals in the molecule, and correctly reproduce the susceptibility versus temperature curve. Our results indicate that it is possible to obtain similar fittings with sets of parameters representing different physical effects and put in evidence the drawbacks of the fitting based on oversimplified magnetic models. In this context, the presented computational strategy can be considered as a useful tool to help in the interpretation of the magnetic data and the validation of the magnetic interaction model in the polynuclear magnetic systems.Ministerio de Ciencia e Innovación de España-CTQ2009-0776

Homeopatía: aportaciones a su historia, legislación y clínica

En este trabajo se trata de establecer una visión clara sobre qué es la homeopatía mediante el enlace de técnicas históricas, normativas y clínicas. La homeopatía es un método terapéutico que lleva empleándose por diferentes profesionales de la salud desde hace más de dos siglos. En una primera revisión bibliográfica se pone en situación el marco histórico que acoge a la homeopatía y a su evolución hasta nuestros días para acercarnos la visión de esta terapéutica, la cual lleva empleándose ya más de tres siglos. Comenzamos con el nacimiento de la homeopatía y todo lo relacionado a su fundador para exponer unas nociones básicas sobre cómo surge y cómo, después de él, otros clínicos la adaptan a su forma de proceder. Además, pondremos en valor diversos médicos homeópatas relevantes en España y profundizaremos en las fuentes primarias a nuestro alcance. Asimismo, nos acercamos a la clínica médica a través de la colaboración con una podóloga que tiene, en una de sus vías de tratamiento, la homeopatía. Dentro de esta sección de la revisión se encuentra, de forma breve y resumida, la regulación de estos medicamentos en nuestro país como parte de las cuestiones sanitarias que se recogen en la norma, ofreciéndose una visión escueta y clara en cuanto a las nociones básicas a tener en cuenta entorno al registro de los medicamentos homeopáticos, la calidad y normas de correcta fabricación de ellos, la dispensación o la farmacovigilancia. Para completar el estudio, abordamos un caso clínico que ha ofrecido un profesional sanitario y completamos esta monografía con una entrevistaUniversidad de Sevilla. Grado en Farmaci

Educación, género e igualdad de oportunidades

Esta colaboración pretende mostrar la complejidad de la desigualdad de género a nivel mundial y en nuestro entorno cultural, proponiendo como principal hipótesis explicativa de dicha desigualdad la situación ancestral de desequilibrio en el reparto del poder existente en los diferentes órdenes de la vida. La situación de inferioridad educativa, profesional y social de las mujeres es tanto causa como consecuencia de dichas desigualdades. Introducir la perspectiva de género en los sistemas sociales parece la forma idónea de avanzar hacia la equidad, equidad necesaria para el desarrollo sostenible, el avance del conocimiento y el desarrollo democrático. Es, además, un imperativo de los desarrollos legislativos de los países desarrollados y una meta prioritaria de los Objetivos del Milenio y de la Educación para Todo

Cultura y televisión, una relación necesaria

La relación entre cultura y televisión suele presentarse como conflictiva e incluso imposible. En este artículo se hace un repaso histórico a la presencia de contenidos culturales en la televisión pública española, TVE, tanto a nivel nacional como regional, para defender la necesidad de la presencia de espacios culturales en televisión

Vinylic Addition Polynorbornene in Catalysis

Vinylic addition polynorbornenes (VA-PNB) result from the insertion polymerization of norbornene or specific norbornene derivatives catalyzed by transition metal com- plexes. The VA-PNB skeleton is completely aliphatic and keeps the bicyclic structure of norbornene. This saturated polymer is thermally and chemically very stable and it is a very robust scaffold to support catalysts or reagents for catalytic applications. Several VA-PNBs are now available with suitable functional groups (halogen, alkenyl, carbonates) that can be used as starting materials to introduce the functionalization of choice by post-polymerization reactions. This has been applied to anchor organocatalysts on VA-PNB as well as ligands that can be used to synthesize supported metal catalysts. The reported examples of the use of VA-PNB-linked catalysts and their recyclability will be presented. VA-PNBs have also proved useful in the context of organotin chemistry to solve the problem of tin contamination by an efficient separation and the reuse of tin byproducts. Its uses in the Stille cross-coupling reaction and tin-hydride radical proc- esses will be discussed.MINECO (SGPI, grant CTQ2016-80913-P)Junta de Castilla y León (grants VA062G18 and VA051P17 and a fellowship to RGL

On the solvability of the Yakubovich linear-quadratic infinite horizon minimization problem

The Yakubovich Frequency Theorem, in its periodic version and in its general nonautonomous extension, establishes conditions which are equivalent to the global solvability of a minimization problem of infinite horizon type, given by the integral in the positive half-line of a quadratic functional subject to a control system. It also provides the unique minimizing pair \lq\lq solution, control\rq\rq~and the value of the minimum. In this paper we establish less restrictive conditions under which the problem is partially solvable, characterize the set of initial data for which the minimum exists, and obtain its value as well a minimizing pair. The occurrence of exponential dichotomy and the null character of the rotation number for a nonautonomous linear Hamiltonian system defined from the minimization problem are fundamental in the analysis.Ministerio de Economía y Competitividad / FEDER, MTM2015-66330-PMinisterio de Ciencia, Innovación y Universidades, RTI2018-096523-B-I00European Commission, H2020-MSCA-ITN-2014INDAM -- GNAMPA Project 201