Influence of the anion nature and alkyl substituents in the behavior of ionic liquids derived from phenylpyridines

© 2017 Quaternary alkyl 2-phenylpyridinium and 2-(2,4-difluorophenyl)pyridinium amines with iodide, hexafluorophosphate and bis(trifluoromethylsulfonyl)imide anions have been fully characterized by 1H NMR, FT-IR and MALDI mass spectroscopic methods and studied by quantum chemistry calculations. The compounds with bis(trifluoromethylsulfonyl)imide anion can be classified as ionic liquids, because they melt at room temperature. The quaternary amines with iodide and hexafluorophosphate anions are solid at 25 °C. The X-ray diffraction characterization of the 2-(2,4-difluorophenyl)-1-methylphenylpyridinium hexafluorophosphate and 1-ethyl-2-(2,4-difluorophenyl)phenylpyridinium hexafluorophosphate show an extensive series of C–H⋯F, C–F⋯π and P–F⋯π intermolecular interactions, which give rise to a supramolecular network. The relationship between the solid-state structures and the melting points is discussed by the evaluation of the thermal behavior based on experimental data from Differentia

Structural, Electronic, and Thermodynamic Properties of the T and B Phases of Niobia: First-Principle Calculations

Different polymorphs of Nb₂O₅ can be obtained depending on the pressure and temperature of calcination leading to different catalytic properties. Two polymorphs of niobia, T-Nb₂O₅ and B-Nb₂O₅, have been investigated by means of density functional/plane waves method. The equation of state predicted that B-Nb₂O₅ phase is more stable than the T-Nb₂O₅ at low temperature; however at high pressure both phases are stable. These results are in good agreement with the available experimental data. The calculated cohesive energies of 6.63 and 6.59 eV·atom^–1 for the B-Nb₂O₅ and T-Nb₂O₅, respectively, also corroborate this conclusion, and it can be compared to the experimental value of 9.56 eV atom^–1 estimated for the most thermodynamically stable phase. The topological analyses based on quantum theory of atoms in molecules (QTAIM) and electron localization function (ELF) were applied and reveal bonds with large ionic character for both phases. The B-Nb₂O₅ presented larger stiffness than T-Nb₂O₅, and the oxygen sites in the T-Nb₂O₅ are more compressible. The density of states comparison for both structures indicates that B-Nb₂O₅ has lower concentration of acid sites compared to T-Nb₂O₅. This result is consistent with the experimental observations that the concentration of Lewis acid sites decreases with the temperature

Formation of self-assembled monolayer of curcuminoid molecules on gold surfaces

We investigated the formation of self-assembled monolayers of two thiophene curcuminoid molecules, 2-thphCCM (1) and 3-thphCCM (2), on polycrystalline gold substrates prepared by immersion of the surfaces in a solution of the molecules during 24 h. The functionalized surfaces were studied by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). Despite the fact that both molecules have the same composition and almost the same structure, these molecules exhibit different behavior on the gold surface, which can be explained by the different positions of the sulfur atoms in the terminal aromatic rings. In the case of molecule 1, the complete formation of a SAM can be observed after 24 h of immersion. In the case of molecule 2, the transition from flat-lying to upright configuration on the surface is still in process after 24 h of immersion. This is attributed to the fact that molecule 2 have the sulfur atoms more exposed than molecule 1.Fil: Berlanga, Isadora. Universidad de Chile; ChileFil: Etcheverry Berríos, Álvaro. Universidad de Chile; ChileFil: Mella, Andy. Universidad de Chile; ChileFil: Jullian, Domingo. Universidad de Chile; ChileFil: Gómez Andrade, Victoria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Chile; ChileFil: Aliaga-Alcalde, Núria. Institució Catalana de Recerca i Estudis Avancats; España. Universitat Autònoma de Barcelona; EspañaFil: Fuenzalida, Victor. Universidad de Chile; ChileFil: Flores, Marcos. Universidad de Chile; ChileFil: Soler, Monica. Universidad de Chile; Chil

Is IIIG9 a New Protein with Exclusive Ciliary Function? Analysis of Its Potential Role in Cancer and Other Pathologies.

The identification of new proteins that regulate the function of one of the main cellular phosphatases, protein phosphatase 1 (PP1), is essential to find possible pharmacological targets to alter phosphatase function in various cellular processes, including the initiation and development of multiple diseases. IIIG9 is a regulatory subunit of PP1 initially identified in highly polarized ciliated cells. In addition to its ciliary location in ependymal cells, we recently showed that IIIG9 has extraciliary functions that regulate the integrity of adherens junctions. In this review, we perform a detailed analysis of the expression, localization, and function of IIIG9 in adult and developing normal brains. In addition, we provide a 3D model of IIIG9 protein structure for the first time, verifying that the classic structural and conformational characteristics of the PP1 regulatory subunits are maintained. Our review is especially focused on finding evidence linking IIIG9 dysfunction with the course of some pathologies, such as ciliopathies, drug dependence, diseases based on neurological development, and the development of specific high-malignancy and -frequency brain tumors in the pediatric population. Finally, we propose that IIIG9 is a relevant regulator of PP1 function in physiological and pathological processes in the CNS

A microarray for assessing transcription from pelagic marine microbial taxa

Metagenomic approaches have revealed unprecedented genetic diversity within microbial communities across vast expanses of the world’s oceans. Linking this genetic diversity with key metabolic and cellular activities of microbial assemblages is a fundamental challenge. Here we report on a collaborative effort to design MicroTOOLs (Microbiological Targets for Ocean Observing Laboratories), a high-density oligonucleotide microarray that targets functional genes of diverse taxa in pelagic and coastal marine microbial communities. MicroTOOLs integrates nucleotide sequence information from disparate data types: genomes, PCR-amplicons, metagenomes, and metatranscriptomes. It targets 19?400 unique sequences over 145 different genes that are relevant to stress responses and microbial metabolism across the three domains of life and viruses. MicroTOOLs was used in a proof-of-concept experiment that compared the functional responses of microbial communities following Fe and P enrichments of surface water samples from the North Pacific Subtropical Gyre. We detected transcription of 68% of the gene targets across major taxonomic groups, and the pattern of transcription indicated relief from Fe limitation and transition to N limitation in some taxa. Prochlorococcus (eHLI), Synechococcus (sub-cluster 5.3) and Alphaproteobacteria SAR11 clade (HIMB59) showed the strongest responses to the Fe enrichment. In addition, members of uncharacterized lineages also responded. The MicroTOOLs microarray provides a robust tool for comprehensive characterization of major functional groups of microbes in the open ocean, and the design can be easily amended for specific environments and research questions