Morpholinium perchlorate

In the title salt, C4H10NO+·ClO4 −, which has three independent formula units, the cations are linked into chains along [100] by N—H⋯O hydrogen bonds. Each cation acts both as a donor and as an acceptor, and every cation makes one N—H⋯O hydrogen bond with a ClO4 − anion. The crystal studied was an inversion twin

Reinvestigation of tris­odium dihydroxido­tetra­oxidoneptunate(VII) dihydrate

The title compound, Na3[NpO4(OH)2]·2H2O, contains distorted tetra­gonal–bipyramidal centrosymmetric [NpO4(OH)2]3− complex anions. The Np—O distances are 1.8975 (7) and 1.8891 (7) Å in the NpO4 group and 2.3451 (7) Å to the OH group. Both Na atoms (one in a general position, the second in a special position on an inversion centre) have a distorted octahedral oxygen environment

Synthesis, X-ray characterization and theoretical study of 3 a ,6:7,9 a-diepoxybenzo [de] isoquinoline derivatives: on the importance of F⋯O interactions

The synthesis, X-ray characterization and Hirshfeld surface analysis of a series of tetrahydrodiepoxybenzo[de]isoquinoline derivatives obtained by the tandem [4+2] cycloaddition between perfluorobut-2-yne dienophile (F3C–C≡C–CF3) and a row of N,N-bis(furan-2-ylmethyl)-4-Rbenzenesulfonamides (bis-dienes, R = Me, F, Cl, Br, I) are reported in this manuscript. The implementation of kinetic/thermodynamic control allowed to obtain both “pincer”- and “domino”-types adducts in good/moderate yields. In the solid state, most of the pincer adducts form self-assembled dimers (R = Me, Cl, Br, I) and, contrariwise, the domino adducts form 1D supramolecular chains, which are described in detail herein. Remarkably, in the self-assembled dimers, bifurcated halogen bonds involving one fluorine atom of the CF3 group and both O-atoms of sulfonamide are formed, which have been analyzed using DFT calculations, QTAIM and NCIplot computational tools.Fil: Grudova, Mariya V.. Peoples’ Friendship University; RusiaFil: Gil, Diego Mauricio. Universidad Nacional de Tucumán. Instituto de Biotecnología Farmacéutica y Alimentaria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biotecnología Farmacéutica y Alimentaria; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Orgánica; ArgentinaFil: Khrustalev, Victor N.. Peoples’ Friendship University; Rusia. Institute of Organic Chemistry ND. Zelinsky; RusiaFil: Nikitina, Eugeniya V.. Peoples’ Friendship University; RusiaFil: Sinelshchikova, Anna A.. Academy of Sciences. Frumkin Institute of Physical Chemistry and Electrochemistry; RusiaFil: Grigoriev, Mikhail S.. Academy of Sciences. Frumkin Institute of Physical Chemistry and Electrochemistry; RusiaFil: Kletskov, Alexey V.. Peoples’ Friendship University; RusiaFil: Frontera, Antonio. Universidad de las Islas Baleares; EspañaFil: Zubkov, Fedor I.. Peoples’ Friendship University; Rusi

Dynamics of Arctic Permafrost Coasts in the 21st Century

Climate warming is particularly pronounced in the Arctic with temperatures rising twice as much as in the rest of the world. It seems natural that this warming has profound effects on the speed of erosion of Arctic coasts, since the majority consists of permafrost, composed of unlithified material and hold together by ice. Permafrost stores approximately 1307 Gt of carbon, which is almost 60 % more than currently being contained in the atmosphere. Understanding the main drivers and dynamics of permafrost coastal erosion is of global relevance, especially since floods and erosion are both projected to intensify. However, the assessment of the impacts of climate warming on Arctic coasts is impaired by little data availability. We reviewed relevant scientific literature on changing dynamics of Arctic coast, potential drivers of these changes and the impacts on the human and natural environment. We provide a comprehensive overview over the state of the art and share our thoughts on how we envision potential pathways of future Arctic coastal research. We found that the overwhelming majority of all studied Arctic coasts is erosive and that in most cases erosion rates per year are increasing, threatening coastal settlements, infrastructure, cultural sites and archaeological remains. The impacts on the natural environment are also manifold and reach from changing sediment fluxes which limit light availability in the water column to a higher input of carbon and nutrients into the nearshore zone with the potential to influence food chains

Intramolecular sp2-sp3 disequalization of chemically identical sulfonamide nitrogen atoms: single crystal X-Ray diffraction characterization, hirshfeld surface analysis and DFT calculations of N-substituted hexahydro-1,3,5-triazines

In this manuscript, the synthesis and single crystal X-ray diffraction characterization of four N-substituted 1,3,5-triazinanes are reported along with a detailed analysis of the noncovalent interactions observed in the solid state architecture to these compounds, focusing on C–H···π and C–H···O H-bonding interactions. These noncovalent contacts have been characterized energetically by using DFT calculations and also by Hirshfeld surface analysis. In addition, the supramolecular assemblies have been characterized using the quantum theory of “atoms-in-molecules” (QTAIM) and molecular electrostatic potential (MEP) calculations. The XRD analysis revealed a never before observed feature of the crystalline structure of some molecules: symmetrically substituted 1,3,5-triazacyclohexanes possess two chemically identical sulfonamide nitrogen atoms in different sp2 and sp3-hybridizations.Fil: Kletskov, Alexey V.. University of Russia; RusiaFil: Gil, Diego Mauricio. Universidad Nacional de Tucumán. Instituto de Biotecnología Farmacéutica y Alimentaria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Biotecnología Farmacéutica y Alimentaria; ArgentinaFil: Frontera, Antonio. Universidad de las Islas Baleares; EspañaFil: Zaytsev, Vladimir P.. University of Russia; RusiaFil: Merkulova, Natalia L.. University of Russia; RusiaFil: Beltsova, Ksenia R.. University of Russia; RusiaFil: Sinelshchikova, Anna A.. University of Russia; RusiaFil: Grigoriev, Mikhail S.. University of Russia; RusiaFil: Grudova, Mariya V.. University of Russia; RusiaFil: Zubkov, Fedor I.. University of Russia; Rusi

New Preparative Approach to Purer Technetium-99 Samples—Tetramethylammonium Pertechnetate: Deep Understanding and Application of Crystal Structure, Solubility, and Its Conversion to Technetium Zero Valent Matrix

99Tc is one of the predominant fission products of 235U and an important component of nuclear industry wastes. The long half-life and specific activity of 99Tc (212,000 y, 0.63 GBq g−1) makes Tc a hazardous material. Two principal ways were proposed for its disposal, namely, long-term storage and transmutation. Conversion to metal-like technetium matrices is highly desirable for both cases and for the second one the reasonably high Tc purity was important too. Tetramethylammonium pertechnetate (TMAP) was proposed here as a prospective precursor for matrix manufacture. It provided with very high decontamination factors from actinides (that is imperative for transmutation) by means of recrystallisation and it was based on the precise data on TMAP solubility and thermodynamics accomplished in the temperature range of 3–68 °C. The structure of solid pertechnetates were re-estimated with precise X-ray structure solution and compared to its Re and Cl analogues and tetrabutylammonium analogue as well. Differential thermal and evolved gas analysis in a flow of Ar–5% H2 gas mixture showed that the major products of thermolysis were pure metallic technetium in solid matrix, trimethylammonium, carbon dioxide, and water in gas phase. High decontamination factors have been achieved when TMAP was used as an intermediate precursor for Tc

Non-equilibrium electroweak baryogenesis from preheating after inflation

We present a novel scenario for baryogenesis in a hybrid inflation model at the electroweak scale, in which the Standard Model Higgs field triggers the end of inflation. One of the conditions for successful baryogenesis, the departure from thermal equilibrium, is naturally achieved at the stage of preheating after inflation. The inflaton oscillations induce large occupation numbers for long-wavelength configurations of Higgs and gauge fields, which leads to a large rate of sphaleron transitions. We estimate this rate during the first stages of reheating and evaluate the amount of baryons produced due to a particular type of higher dimensional CP violating operator. The universe thermalizes through fermion interactions, at a temperature below critical, $T_{rh} < 100$ GeV, preventing the wash-out of the produced baryon asymmetry. Numerical simulations in (1+1) dimensions support our theoretical analysis.Comment: 11 pages, ReVTeX, 16 figures inserted with epsf. Small changes in the introduction and new reference

Arctic coastal dynamics of Eurasia – results of two ACD-related INTAS projects : extended abstract

Under the framework of the Arctic Coastal Dynamics (ACD) program two projects of the International Association for the Promotion of Co-operation with Scientists from the New Independent States of the Former Soviet Union (INTAS) focused on ACD related topics. The objectives of the first project "Arctic coastal dynamics of Eurasia: classification, modern state and prediction of its development based on GIS technology" (2002-2004) had been to develop a coastal classification and to generate GIS based map products for the coastal Zone of the Eurasian Arctic. The Russian Part of the circum-Arctic ACD classification and segmentation has been completed within this project. The overall objective of the second project "Arctic coasts of Eurasia: dynamics, sediment budget and carbon flux in connection with permafrost degradation" (2002-2005) is to quantify the material flux through coastal erosion in order to improve our understanding of the Arctic sediment and organic carbon budget. This presentation summarizes the main results of the two projects and provides an overview of more specific results which are shown in a series of Posters

New Synthetic Thrombin Inhibitors: Molecular Design and Experimental Verification

BACKGROUND: The development of new anticoagulants is an important goal for the improvement of thromboses treatments. OBJECTIVES: The design, synthesis and experimental testing of new safe and effective small molecule direct thrombin inhibitors for intravenous administration. METHODS: Computer-aided molecular design of new thrombin inhibitors was performed using our original docking program SOL, which is based on the genetic algorithm of global energy minimization in the framework of a Merck Molecular Force Field. This program takes into account the effects of solvent. The designed molecules with the best scoring functions (calculated binding energies) were synthesized and their thrombin inhibitory activity evaluated experimentally in vitro using a chromogenic substrate in a buffer system and using a thrombin generation test in isolated plasma and in vivo using the newly developed model of hemodilution-induced hypercoagulation in rats. The acute toxicities of the most promising new thrombin inhibitors were evaluated in mice, and their stabilities in aqueous solutions were measured. RESULTS: New compounds that are both effective direct thrombin inhibitors (the best K(I) was <1 nM) and strong anticoagulants in plasma (an IC(50) in the thrombin generation assay of approximately 100 nM) were discovered. These compounds contain one of the following new residues as the basic fragment: isothiuronium, 4-aminopyridinium, or 2-aminothiazolinium. LD(50) values for the best new inhibitors ranged from 166.7 to >1111.1 mg/kg. A plasma-substituting solution supplemented with one of the new inhibitors prevented hypercoagulation in the rat model of hemodilution-induced hypercoagulation. Activities of the best new inhibitors in physiological saline (1 µM solutions) were stable after sterilization by autoclaving, and the inhibitors remained stable at long-term storage over more than 1.5 years at room temperature and at 4°C. CONCLUSIONS: The high efficacy, stability and low acute toxicity reveal that the inhibitors that were developed may be promising for potential medical applications