Search results for "Stack"
showing 10 items of 392 documents
Stabilisation of Exotic Tribromide (Br3−) Anions via Supramolecular Interaction with A Tosylated Macrocyclic Pyridinophane. A Serendipitous Case.
2020
Tetraaza-macrocyclic pyridinophane L-Ts, decorated with a p-toluenesulfonyl (tosyl
Crystal structure of bis(ethylenedithio)tetrathiafulvalenium μ2-acetato-bis[tribromidorhenate(III)] 1,1,2-trichloroethane hemisolvate
2016
The crystal structure of a binuclear monocarboxylato dirhenium(III) complex with a fulvalene derivative is reported. This compound represents a radical cation salt containing a cluster unit with rhenium–rhenium quadruple bond.
Crystal structure of 2-hydroxyimino-2-(pyridin-2-yl)-N'-[1-(pyridin-2-yl)ethylidene]acetohydrazide
2014
The molecule of the title compound is approximately planar with the planes of the two pyridine rings inclined to one another by 5.51 (7)°. In the crystal, molecules are linked by bifurcated O—H⋯(O,N) hydrogen bonds, forming inversion dimers, which are in turn linked via C—H⋯O and C—H⋯N hydrogen bonds, forming sheets lying parallel to (502).
Tris(1,10-phenanthroline-κ2N,N′)nickel(II) bis(hexafluoridophosphate)
2018
The asymmetric unit of the title compound, [Ni(C36H24N6)3](PF6)2, contains one and a half nickel(II) complex dications and three hexafluoridophosphate anions, one of the dications having crystallographic twofold rotational symmetry. Each NiIIatom displays a distorted octahedral coordination geometry provided by the six N atoms of three bidentate 1,10-phenanthroline ligands with bite angles of 79.68 (11)–80.76 (12)°. In the crystal, C—H...F hydrogen bonds link the anions and dications into a three-dimensional supramolecular framework. Within the framework complex dications with twofold rotational symmetry are linked by weak π–π stacking interactions [centroid-to-centroid distances = 3.712 (2…
Intramolecular 1,5-S...N σ-hole interaction in (E)-N′-(pyridin-4-ylmethylidene)thiophene-2-carbohydrazide
2020
The hydrazide-hydrazone forms inverse dimers via hydrogen bonding, but its conformation is defined by the presence of an intramolecular chalcogen bond. Electrostatic forces dominate in the crystal packing and give rise to a layered supramolecular structure.
2-(3-Methyl-2-oxo-1,2-dihydroquinoxalin-1-yl)acetic acid dihydrate
2018
In the title compound, C11H10N2O3·2H2O, the constituent atoms of the dihydroquinoxaline moiety deviate from the mean plane of the unit by +0.0572 (8) to −0.0874 (8) Å while the acetic acid substituent is nearly orthogonal to this plane. The crystal packing consists of corrugated layers constructed by O—H...O, O—H...N and C—H...O hydrogen bonds, which also involve the lattice water molecules. O—H...O hydrogen bonds and π–π stacking interactions hold these layers together.
Substituent effects in nitro derivatives of carbazoles investigated by comparison of low-temperature crystallographic studies with density functional…
2014
The crystal structure of 9H-carbazole, C12H9N, (I), has been redetermined at low temperature for use as a reference structure in a comparative study with the structures of 1-nitro-9H-carbazole, C12H8N2O2, (II), and 9-nitrocarbazole, C12H8N2O2, (III). The molecule of (I) has crystallographically imposed mirror symmetry (Z′ = 0.5). All three solid-state structures are slightly nonplanar, the dihedral angles between the planes of the arene and pyrrole rings ranging from 0.40 (7)° in (III) to 1.82 (18)° in (II). Nevertheless, a density functional theory (DFT) study predicts completely planar conformations for the isolated molecules. To estimate the influence of nitro-group substitution on aroma…
Vietnes Stack Overflow satura analīze
2018
Stack Overflow ir vispopulārākā jautājumu un atbilžu vietne jautājumiem par programmēšanas problēmām. Darbā tiks analizēts vietnes Stack Overflow datu izraksts. Ar datizraces palīdzību datu izrakstā tiks meklētas sakarības starp jautājumu, atbilžu un lietotāju objektiem. Padziļināta analīze tiek veikta, lai salīdzinātu Latvijas lietotāju ar vidējo Stack Overflow lietotāju.
Analysis of radionuclide concentration in air released through the stack of a radiopharmaceutical production facility based on a medical cyclotron
2015
Abstract Positron emitting radionuclides are increasingly used in medical diagnostics and the number of radiopharmaceutical production facilities have been estimated to be growing worldwide. During the process of production and/or patient administration of radiopharmaceuticals, an amount of these radionuclides might become airborne and escape into the environment. Therefore, the analysis of radionuclide concentration in the air released to the stack is a very important issue to evaluate the dose to the population living around the plant. To this end, sampling and measurement of radionuclide concentration in air released through the stack of a Nuclear Medicine Center (NMC), provided with a c…
Crystal structures of allyltriphenyl-phosphonium halogenocuprates(I)
2013
Alternating-current electrochemical synthesis is used to obtain for the first time halogenocuprates of an allyl derivative of phosphonium of the composition (CH2=CHCH2(C6H5)3P)CuX2 (X = Br (I), Cl (II)). Compound I crystallizes in the space group P21, a = 9.6341(3) A, b = 12.4167(4) A, c = 9.9618(4) A, β = 117.484(5)°, Z = 2. Compound II crystallizes in the space group P21/n, a = 9.9725(5) A, b = 15.4586(8) A, c = 13.7557(5) A, β = 90.429(4)°, Z = 4. In the structures of I and II quasilinear CuX 2 − anions are held by C-H…X hydrogen bonds inside a framework formed by the stacking of phenyl groups from CH2=CHCH2(C6P5)3P+ cations. Allyl groups are not involved in coordination with copper(I) a…