Micro-scale Experiments in the Increasingly Fashionable Laboratory in High Schools

Objective: Experimental activities in laboratories are an important part in teaching and learning chemistry. Nevertheless, its implementation may be limited by the lack of material, instrument and above all the risk involved in doing so in the laboratory. Not only because of the cost of the reagents, but also because of the safety of the students in the classroom. That is why the use of simple micro-scale experiments turns out to be a benefit for the teaching of chemistry to high school students. Methods: Micro-scale practices also facilitate the implantation of constructivist laboratory practices, presented as small investigations, displacing traditional laboratory practices. The design of practices from a constructivist approach allows working all or some aspects of the scientific method. A constructivist methodology will increase the student’s interest in the subject and bring them closer to the scientific method, which will provoke the development of their observation capacity, the ability to make hypotheses, the skill in the design of experimental setups, discussing results, drawing conclusions and relating empirical data to theoretical principles. In contrast, traditional practices are usually prescription-type practices completely lack the scientific method. Since there are numerous difficulties in implementing practices with a constructivist methodology, both methods may be considered according to the space, time, and materials possibilities. Conclusion: The micro-scale experiments is useful for different reasons: reduces chemical use by promoting waste reduction of the source, save money, improves safety, may be carry out in class and sometimes at home, decreases experiment time and student carry out the experiments by themselves which is important for a significant learning

Programación didáctica sintética 4º ESO Física y Química

Treball Final de Màster Universitari en Professor/a d'Educació Secundària Obligatòria i Batxillerat, Formació Professional i Ensenyaments d'Idiomes. Codi SAP119. Curs: 2017/2018El presente documento es un trabajo de final de Máster de Profesorado de Educación Secundaría obligatoria y Formación profesional. El trabajo se enmarca dentro de la modalidad de Programación Didáctica, por lo que se desarrolla una programación didáctica sintética en la especialidad de Física y Química y en el nivel de 4ºESO. Se ha tomado con referencia, para contextualizar el trabajo, el Instituto Miralcamp de Vila-real

A Tetraferrocenyl-Resorcinarene Cavitand as a Redox-Switchable Host of Ammonium Salts

Tetraannulation of a resorcinarene-octaamino cavitand with ferrocenecarboxaldehyde allows the preparation of a tetrabenzimidazole-resorcinarene cavitand with four ferrocenyl moieties directly linked to the C2 atom of the imidazole units. Oxidation of the four ferrocenyl moieties produces important structural modifications of the molecule, as indicated by DFT calculations performed for the neutral and tetraoxidized forms of the cavitand. By means of 1H NMR spectroscopic analysis, the encapsulating properties of the new tetraferrocenyl-resorcinarene cavitand toward a series of ammonium salts were evaluated, and a clear cutoff point in binding affinity with respect to size was observed. Cyclic voltammetric studies allowed us to estimate the relative association constants for the neutral and oxidized forms of the cavitand, thus indicating that the guest was bound to the neutral (reduced) state of the cavitand and was released from the oxidized form. These redox-addressable conformational and binding properties of the resorcinarene-tetraferrocenyl cavitand constitute all the necessary features of a redox-switchable molecular gripper. By means of mass-spectrometric analysis, we could unambiguously confirm the molar stoichiometry of the host–guest complex (1:1) and assess the strong guest encapsulation, as indicated by triggering the covalent coupling between host and guest in the gas phase.MEC of Spain (CTQ2011-24055/BQU and CTQ2014-54071-P) and the Universitat Jaume I (P11B2014-02

CIBERER: Spanish national network for research on rare diseases: A highly productive collaborative initiative

13 páginas,1 figura, 3 tablas, 1 apéndice. Se extraen los autores pertenecientes a The CIBERER network que trabajan en Centros del CSIC del Appendix ACIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a public national consortium created in 2006 under the umbrella of the Spanish National Institute of Health Carlos III (ISCIII). This innovative research structure comprises 11 different specific areas dedicated to the main public health priorities in the National Health System. CIBERER, the thematic area of CIBER focused on rare diseases (RDs) currently consists of 75 research groups belonging to universities, research centers, and hospitals of the entire country. CIBERER's mission is to be a center prioritizing and favoring collaboration and cooperation between biomedical and clinical research groups, with special emphasis on the aspects of genetic, molecular, biochemical, and cellular research of RDs. This research is the basis for providing new tools for the diagnosis and therapy of low-prevalence diseases, in line with the International Rare Diseases Research Consortium (IRDiRC) objectives, thus favoring translational research between the scientific environment of the laboratory and the clinical setting of health centers. In this article, we intend to review CIBERER's 15-year journey and summarize the main results obtained in terms of internationalization, scientific production, contributions toward the discovery of new therapies and novel genes associated to diseases, cooperation with patients' associations and many other topics related to RD research.This study has been funded by Instituto de Salud Carlos III (ISCIII) and Spanish Ministry of Science and InnovationPeer reviewe

The importance of ligand design for the development of supramolecular catalysts and ion receptors

La tesis está dividida en dos partes claramente diferenciadas. La primera parte trata sobre aspectos concernientes a la catálisis supramolecular. Los trabajos descritos están basados en el diseño de nuevos ligandos N-heterociclicos con diferentes topologías y funcionalidades, los cuales fueron coordinados a diferentes centros metálicos. Los complejos sintetizados fueron caracterizados y estudiados en catálisis, con el objetivo principal de estudiar los efectos producidos por los ligandos orgánicos debido a interacciones del tipo no covalentes. Estos complejos o catalizadores también fueron soportados y estudiados en catálisis heterogénea. La segunda parte de la tesis se centra en estudios de química supramolecular host-guest. Los trabajos descritos en esta parte describen la preparación de nuevos receptores ionicos basados en esqueletos de resorcinareno cavitando y/o esqueletos de naturaleza tripodal. Se estudiaron y analizadores los diferentes modos de interacción y las constantes de asociación hacia una gran variedad de guests de diferente naturaleza.The present thesis is divided in two different parts. Part 1 is titled the importance of ligand design for the development of supramolecular catalysts. This part includes three different chapters: introduction chapter 1, chapter 2 and chapter 3. Chapter 1 shows a brief overview of the most interesting items related to supramolecular catalysis. In chapter 2 is described the synthesis and characterization of three different p-xylylbis-benzimidazolylidene iridium and rhodium complexes. Chapter 3 reports the synthesis, characterization and catalytic studies of different palladium, iridium and rhodium complexes, which are formed by N-heterocyclic ligands featuring different topologies, and some of them decorated with pyrene functionalities. The importance and influence of these ligands in the conformational and catalytic behaviour of the metal complexes is studied in detail, providing evidences of the effects produces due to non-covalent interactions such as π-π interactions. Part 2 is titled the importance of ligand design for the development of ion receptors. This part includes three chapters: introduction chapter 4, chapter 5 and chapter 6. Chapter 4 is a brief introduction of the most relevant aspects related to supramolecular host-guest chemistry. The approaches described in chapter 5 consist of two different strategies for the preparation of imidazole resorcinarene based cavitands for the recognition of anions or cations. Chapter 6 reports the synthesis of tris-azolium and tris-iodoazolium tripodal receptors for the recognition of anions. In both chapters (5 and 6) are studied the binding capabilities of the receptors towards several ions, showing the importance of the development in ligand design to improve the properties of the receptors.Programa de Doctorat en Cièncie

Unveiling the Importance of π-Stacking in Borrowing-Hydrogen Processes Catalysed by Iridium Complexes with Pyrene Tags

This work describes the preparation of a series of pyrene-tagged N-heterocyclic carbene complexes of iridium, and their use in two benchmark borrowing hydrogen reactions: the reduction of ketones by transfer hydrogenation and the β-alkylation of secondary alcohols with primary alcohols. The detailed study of these homogeneously catalysed reactions reveals several important implications regarding the strong influence of the pyrene tags in the catalysts. First, the catalytic activity is partially inhibited by addition of an external amount of pyrene, but only when pyrene-tagged catalysts and aromatic substrates are used. Second, the rate order of the reaction is highly dependent on the nature of the substrates and the ligand. When pyrene-tagged catalysts and aromatic substrates are used, the reaction follows a zero-order dependence on the concentration of the substrate. All other combinations afford a second-order rate in the substrates. And third, the presence or absence of the pyrene functionality in the catalyst also influences the reaction order with respect to the concentration of the catalyst. Pyrene-containing catalysts display a fractional rate order of below 1. Finally, two pyrene-tagged catalysts were supported onto reduced-graphene oxide (rGO), and used as heterogeneous catalysts. While the dimetallic catalyst was effectively recycled 12 times, the monometallic catalyst maintained its activity for only three runs.MEC of Spain (CTQ2014-51999-P) and the Universitat Jaume I (P11B2014-02

Phenylene- and Biphenylene-Bridged Bis-Imidazolylidenes of Palladium. Influence of the Presence of Pyrene Tags on the Catalytic Activity of the Complexes

A series of dimetallic complexes with N-heterocyclic carbene ligands with formally identical stereoelectronic properties have been obtained and fully characterized. The dimetallic complexes were bridged by bis-imidazolylidenes, with different spacers (phenylene and biphenylene). The N substituents were methyl or methylpyrene groups. The related monometallic complexes were also obtained. The catalytic properties of the complexes were tested in the acylation of aryl halides with hydrocinnamaldehyde and in the Suzuki–Miyaura coupling between aryl halides and arylboronic acids. In general, the dimetallic complexes display better activities than the monometallic analogues. The results also indicate that those complexes with pyrene groups at the N substituents display better catalytic activities than those with <i>N</i>-methyl groups. These observations are interpreted as a consequence of the π stacking interaction between the substrates and the pyrene groups in the pyrene-containing catalysts, which may provide some beneficial catalytic properties. The addition of a catalytic amount of pyrene to the Suzuki–Miyaura coupling reactions results in a partial inhibition of the activities of the complexes with the pyrene substituents, while the activity of the complexes with the <i>N</i>-methyl groups is not affected

A resorcinarene-based tetrabenzoimidazolylidene complex of rhodium

A tetrabenzoimidazolium-resorcinarene cavitand was used for the preparation of a tetra-benzoimidazolylidene of rhodium, which is unprecedented in the field of poly-NHC metal complexes. Both, the experimental and computational analysis of the molecule reveal a distorted vase conformation as the most stable one, although several non-interconverting conformational isomers due to the restricted rotation about the Rh-C(carbene) bond coexist in the product. There is a fluxional behaviour involving the vase-kite interconversion. The main interactions between the arms of the cavitand are mostly concentrated on the terminal organometallic fragments attached to the NHC, along with those between -CH3 and N-heterocyclic carbene ring from benzoimidazoles

Tripodal halogen bonding iodo-azolium receptors for anion recognition

The synthesis, characterization and anion binding properties of 1,3,5-tri-substituted benzene platform-based tripodal receptors containing halogen bonding (XB) iodo-imidazolium and iodo-triazolium motifs, and hydrogen bonding (HB) analogues are described. Proton NMR anion binding investigations reveal the XB receptors are superior halide complexants compared to hydrogen bonding (HB) receptor analogues, with the iodo-imidazolium tripodal receptor exhibiting notably higher association constant values in comparison to the iodo-triazolium host system. In contrast, the HB tripod receptors, display higher affinities for dihydrogen phosphate than the XB receptors. Computational DFT and molecular dynamics were used to corroborate the experimental observations, and to give a clearer insight into the intimate nature of halide binding. The studies reveal a fundamental different binding behavior for the imidazolium-based and the iodo-imidazolium-based receptors.We gratefully acknowledge nancial support from MEC of Spain (CTQ2014-51999-P and CTQ2014-54071-P) and the Universitat Jaume I (P11B2014-02). We are grateful to the Serveis Centrals d'Instrumentaci´o Cient´ıca (SCIC) of the Universitat Jaume I for providing with spectroscopic facilities. We would also like to thank the Generalitat Valenciana for a fellowship (S-R.-B.)

Coordination singularities of a bis(p-xylyl)bis(benzimidazolylidene) ligand and the bis-iridium and -rhodium-related complexes

The reaction of bis(α,α′-p-xylyl)bis(benzimidazolium) dichloride with [IrCpCl2]2 or [RhCl(COD)]2 affords the corresponding dimetallic bis-N-heterocyclic carbene complexes of Ir and Rh. The reaction with the iridium complex occurs by the transmetalation method, in the presence of Ag2O, while the reaction with the rhodium complex is carried out in the presence of NaOtBu. The two complexes display an anti configuration of the bis-NHC ligand, with the two metal atoms pointing at different faces of the bis-carbene ligand. In both complexes, the two metal fragments disclose different coordination environments (in-out, with respect to the inner and outer part of the cyclophane-bis-NHC), as a consequence of noncovalent interactions. DFT calculations have been used to rationalize this "less intuitive" coordination singularity. The reaction of the bis(α,α′-p-xylyl)bis(benzimidazolium) dichloride with [RhCl(CO)2]2 in the presence of Ag2O affords a dirhodium complex in which the two metals are on the same side of the ligand, which adopts a syn conformation. In the latter case, the two metals are bridged by a chloride and hydroxyl ligands, therefore facilitating the syn disposition of the ligand