Crystal structure of the non-steroidal anti-inflammatory drug (NSAID) tolmetin sodium

The asymmetric unit of the title compound, sodium 2-[1-methyl-5-(4-methylbenzoyl)-1H-pyrrol-2-yl]acetate dihydrate, Na+·C15H14NO3 −·2H2O, contains two sodium cations, two organic anions (A and B) and two water molecules. The coordination geometry around the sodium cations corresponds to a distorted octahedron. Each pair of sodium cations (A–A or B–B) is chelated by two bridging anions coordinated by the O atoms of the deprotonated carboxylic groups, and each sodium atom is coordinated by an O atom of a third anion, which connects pairs of sodium atoms, and a water molecule. As a result, a two-dimensional polymer is formed in the crystal. Hirshfeld surface analysis and two-dimensional fingerprint plots were used to analyze the intermolecular contacts present in the crystal.

Elemental Chalcogen (Se, S) in PEG-400 to the Synthesis of Seleno- and Thioflavones from 2-Chlorophenyl Ethynyl Ketone and Nucleophilic Species of Chalcogen

An alternative green method was developed for the synthesis of thio- and selenoflavones by the ring closure of 2-chlorophenyl ethynyl ketone with NaHY (Y = S, Se). These nucleophilic chalcogen species were generated in situ using NaBH4 to reduce the elemental chalcogen in the presence of polyethylene glycol-400 (PEG-400). The efficiency of this reaction is strongly dependent on the PEG-400 solvent, acting like a crown ether, complexing with the sodium atom of NaHY species, making the chalcogen nucleophile more active. The synthetic protocol proceeded efficiently at 100 °C under argon, using a range of 2-chlorophenyl ethynyl ketone containing alkyl, aryl, or vinyl groups and the sulfur and selenium chalcogen. By this efficient and simple approach, 18 chalcogenoflavones were obtained in good to excellent yields after 2 h.

Диффузионная динамика ридберговских состояний в поле излучения с непрерывным спектром

Redistribution of population and ionization of atomic Rydberg states due to multistep cascade transitions between states under the influence of radiation with continuous spectrum is considered. Consideration is carried up both by simulation of kinetic equations for state populations and with the use of a diffusion approximation based on the Fokker-Planck equation. On the example of sodium atom under the influence of radiation with rectangular spectrum a good agreement between the diffusion approximation and the kinetic equation simulation is shown. In the frame of the diffusion approximation some estimations are derived for the state populations, ionization rates and minimal spectral density of radiation necessary for significant ionization.

s-Block metal scorpionates – A new sodium hydrido-tris(3,5-dimethyl-1-pyrazolyl)borate salt showing an unusual core stabilized by bridging and terminal O-bonded DMSO ligands

Dissolution of [(μ-Me2CO)3(NaTp*)2] (1) (Tp* = hydrido-tris(3,5-dimethyl-1-pyrazolyl)borate) in DMSO at room temperature leads to the growth of colourless crystals characterized as the new salt [Na2Tp*(μ-Me2SO)3(Me2SO)3] [NaTp*2] (2). 2 crystallized in the trigonal space group R3 with Z = 3, a = 14.1227(2) Å, b = 14.1227(10) Å, c = 33.9685(2) Å, and V = 5867.35(17) Å3. Interestingly, anion and cation of 2 both contain the Tp* ligand. Moreover, the cationic moiety highlights an unusual sodium atom hexacoordinated by six DMSO molecules acting as O-bonded ligands. Three of which exhibit a bridging coordination mode and three are in terminal position. To the best of our knowledge, the framework of [Na2Tp*(μ-Me2SO)3(Me2SO)3] is unprecedented.

The Microstructural Transformation and Dynamical Properties in Sodium-silicate: Molecular Dynamics Simulation

Molecular dynamics simulation of sodium-silicate has been carried out to investigate the microstructural transformation and diffusion mechanism. The microstructure of sodium silicate is studied by the pair radial distribution function, distribution of SiOx (x=4,5,6), OSiy (y=2,3) basic unit, bond angle distribution. The simulation results show that the structure of sodium silicate occurs the transformation from a tetrahedral structure to an octahedral structure under pressure. The additional network-modifying cation oxide breaking up this network by the generation of non-bridging O atoms and it has a slight effect on the topology of SiOx and OSiy units. Moreover, the diffusion of network- former atom in sodium-silicate melt is anomaly and diffusion coefficient for sodium atom is much larger than for oxygen or silicon atom. The simulation proves two diffusion mechanisms of the network-former atoms and modifier atoms.

First measurements of the Mesospheric Magnetic Field in the Auroral Zone by means of laser

<p>In December 2019, for the first time, we were able to remotely measure the magnetic field in the mesospheric sodium layer, in the auroral zone.</p><p>By means of laser optical pumping and Larmor-resonance detection, it is possible to use the naturally occurring sodium layer in the mesosphere to measure Earth’s magnetic field magnitude at 90 km above ground. This is an altitude otherwise only accessible by rockets, which only will provide point measurements of very short time scales.</p><p>During the winter of 2019-20 we have applied a cw sum-frequency fasor/laser for probing the sodium-atom Larmor resonance at the Artic Lidar Observatory for Mesospheric Research (ALOMAR) at Andøya in northern Norway in order to measure and monitor the magnetic field in situ in the high latitude mesosphere over longer time scales.</p><p>The technique, which has been proved earlier at mid-latitudes, has now been confirmed and applied to high latitudes in the auroral zone during disturbed auroral and geomagnetic conditions. The magnetic field in the auroral zone is close to vertical making our measurements a notable achievement since the beam is closer to parallel with the magnetic field, contary to earlier measurements being closer to perpendicular as shown as best by theory.</p><p>This opens up for a completely new domain of measurements of externally generated geomagnetic variations related to currents in the magnetosphere-ionosphere system.</p><p>Here we report on the instrumental setup, and discuss our measurements of the mesospheric magnetic field.</p>