scholarly journals Crystal Structures of New Ivermectin Pseudopolymorphs

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 172
Author(s):  
Kirill Shubin ◽  
Agris Bērziņš ◽  
Sergey Belyakov
Keyword(s):  
Crystal Structure ◽  
Molecular Conformation ◽  
Methyl Tert Butyl Ether ◽  
Minor Role ◽  
Scanning Calorimetry ◽  
Orthorhombic Crystal ◽  
Monoclinic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Space Group ◽  
Structure Space

New pseudopolymorphs of ivermectin (IVM), a potential anti-COVID-19 drug, were prepared. The crystal structure for three pseudopolymorphic crystalline forms of IVM has been determined using single-crystal X-ray crystallographic analysis. The molecular conformation of IVM in crystals has been compared with the conformation of isolated molecules modeled by DFT calculations. In a solvent with relatively small molecules (ethanol), IVM forms monoclinic crystal structure (space group I2), which contains two types of voids. When crystallized from solvents with larger molecules, like γ-valerolactone (GVL) and methyl tert-butyl ether (MTBE), IVM forms orthorhombic crystal structure (space group P212121). Calculations of the lattice energy indicate that interactions between IVM and solvents play a minor role; the main contribution to energy is made by the interactions between the molecules of IVM itself, which form a framework in the crystal structure. Interactions between IVM and molecules of solvents were evaluated using Hirshfeld surface analysis. Thermal analysis of the new pseudopolymorphs of IVM was performed by differential scanning calorimetry and thermogravimetric analysis.

scholarly journals (R)-Baclofen [(R)-4-amino-3-(4-chlorophenyl)butanoic acid]

2022 ◽  
Vol 78 (1) ◽  
Author(s):  
Feodor Belov ◽  
Alexander Villinger ◽  
Jan von Langermann
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Title Compound ◽  
Single Crystal Xrd ◽  
Butanoic Acid ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Space Group ◽  
Structure Space

This article provides the first single-crystal XRD-based structure of enantiopure (R)-baclofen (form C), C10H12ClNO2, without any co-crystallized substances. In the enantiopure title compound, the molecules arrange themselves in an orthorhombic crystal structure (space group P212121). In the crystal, strong hydrogen bonds and C—H ... Cl bonds interconnect the zwitterionic molecules.

Electron density, disorder and polymorphism: high-resolution diffraction studies of the highly polymorphic neuralgic drug carbamazepine

2016 ◽  
Vol 72 (1) ◽  
pp. 39-50 ◽  
Author(s):  
Ioana Sovago ◽  
Matthias J. Gutmann ◽  
Hans Martin Senn ◽  
Lynne H. Thomas ◽  
Chick C. Wilson ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Diffraction Data ◽  
Structural Formula ◽  
Orthorhombic Crystal ◽  
Monoclinic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Space Group ◽  
X Ray ◽  
Monoclinic Crystal Structure

Analysis of neutron and high-resolution X-ray diffraction data on form (III) of carbamazepine at 100 K using the atoms in molecules (AIM) topological approach afforded excellent agreement between the experimental results and theoretical densities from the optimized gas-phase structure and from multipole modelling of static theoretical structure factors. The charge density analysis provides experimental confirmation of the partially localized π-bonding suggested by the conventional structural formula, but the evidence for any significant C—N π bonding is not strong. Hirshfeld atom refinement (HAR) gives H atom positional and anisotropic displacement parameters that agree very well with the neutron parameters. X-ray and neutron diffraction data on the dihydrate of carbemazepine strongly indicate a disordered orthorhombic crystal structure in the space groupCmca, rather than a monoclinic crystal structure in space groupP21/c. This disorder in the dihydrate structure has implications for both experimental and theoretical studies of polymorphism.

Analysis Microstructure of La0.7(Sr1-xCax)0.3MnO3 Prepared by Sol-Gel Method

2020 ◽  
Vol 855 ◽  
pp. 140-144
Author(s):  
Sitti Ahmiatri Saptari ◽  
Redho Aulia Putra ◽  
Arif Tjahjono ◽  
Anugrah Azhar ◽  
Ikhwan Nur Rahman
Keyword(s):  
Crystal Structure ◽  
Dopant Concentration ◽  
Sol Gel ◽  
Orthorhombic Crystal ◽  
Structure Transition ◽  
Orthorhombic Crystal Structure ◽  
Gel Method ◽  
Space Group ◽  
Sol Gel Method ◽  
Ion Substitution

Perovskite-based on manganite La0.7(Sr1-xCax)0.3MnO3 (x = 0, 0.3, 0.5, 0.7) has been successfully synthesized using by sol-gel method. All sample was characterized by using XRD (X-Ray Diffraction) obtain a single phase without impurities peak. The transition of crystal structure transition, lattice parameters, cell unit volume, crystal size, bond length (Mn-O), and <Mn-O-Mn> bond angles caused by Ca2+ ion substitution. Dopant concentration x = 0 - 0.5 shows that the sample has a rhombohedral crystal structure with space group R-3c and orthorhombic crystal structure with space group P n m a at dopant concentration x = 0.7. The results of SEM (Scanning Electron Microscope) characterization show a difference in grain size with the addition of Ca2+ ion substitution.

scholarly journals Luminescent properties of Eu-doped magnetic Na3FeF6

RSC Advances ◽  
2018 ◽  
Vol 8 (67) ◽  
pp. 38410-38415 ◽  
Author(s):  
Hong Jia ◽  
Yiping Zhou ◽  
Xiaoyan Wang ◽  
Weiying Zhang ◽  
Xun Feng ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Luminescent Properties ◽  
Monoclinic Crystal ◽  
Space Group ◽  
Iron Fluoride ◽  
Structure Space ◽  
Monoclinic Crystal Structure

Sodium iron fluoride (Na3FeF6) is a colorless ferromagnetic fluoride with a monoclinic crystal structure (space group P21/c), and it is expected to be an ideal platform for exploring magneto-optical interactions.

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

scholarly journals Orthorhombic crystal structure and oxygen deficient cluster distribution model for YBa2Cu3−xAlxO6+δ superconductor

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
P. Manju ◽  
Neeraj K. Rajak ◽  
Andrews P. Alex ◽  
Vinayak B. Kamble ◽  
D. Jaiswal-Nagar
Keyword(s):  
Crystal Structure ◽  
Distribution Model ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Cluster Distribution

Thermal enhancement of 2H11/2→4I15/2 up-conversion luminescence of Er3+ doped K2Yb(PO4)(MoO4) phosphors

2021 ◽  
Author(s):  
Hongqiang Cui ◽  
Yongze Cao ◽  
Lei Zhang ◽  
Yuhang Zhang ◽  
Siying Ran ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Reaction Method ◽  
X Ray ◽  
Thermal Enhancement

Er3+ with different concentrations doped K2Yb(PO4)(MoO4) phosphors were prepared by a solid-state reaction method, and the layered orthorhombic crystal structure of the samples was confirmed by X-ray diffraction (XRD). Under...

Ein tricyclisches Tetraboradisiladodecan aus Dimethyl-di-1-propinylsilan und Ethyldiboranen(6) / A Tricyclic Tetraboradisiladodecane from Dimethyl-di-1-propynylsilane and Ethyldiboranes(6)

1995 ◽  
Vol 50 (3) ◽  
pp. 439-447 ◽  
Author(s):  
Roland Köster ◽  
Günter Seidel ◽  
Roland Boese ◽  
Bernd Wrackmeyer
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Structure Space ◽  
Thermal Elimination

The exhaustive hydroboration of the (C ≡ C )-groups in Me2Si(C ≡ CMe)2 (A ) by adding ethyldiboranes(6) at room temperature is presumed to lead initially to the formation of a mixture of the threo- and erythro-3,3,5,6-tetrakis(diethylboryl)-4,4-dimethyl-4-silaheptanes (1a , b). The threo-1a reacts further by borane catalysed intermolecular condensation to the substituted disilatetraboratricyclo[6.2.1.16.9]dodecane 2 with the formula , whose crystal structure [space group C2/c, a = 19.696(2), b = 10.371(1), c = 16.580(2) Å; β = 125.90(1)°; at 122 K] has been established by X -ray diffraction. In contrast, the erythro-1b undergoes intramolecular, thermal elimination of Et3B to give the 1,2-diethyl-2,4-bis(diethylboryl)- 3,3,5-trim ethyl-3-silaborolane (4). If A is added to an excess of undiluted B (“hydridebath”), then the two substituted diastereomers of the 1-carba-arachno-pentaboranes(10) (endo/exo-Et,SiH Me2) (3a, b), are formed preferentially as the result of an initial Si-C ≡-c le a v e d hydroboration.

Darstellung und Struktur der Verbindungen MgCuP, BaCuP(As) und BaAgP(As) / Preparation and Crystal Structure of MgCuP, BaCuP(As), and BaAgP(As)

1979 ◽  
Vol 34 (10) ◽  
pp. 1373-1376 ◽  
Author(s):  
Albrecht Mewis
Keyword(s):  
Crystal Structure ◽  
Space Group ◽  
Lattice Constants ◽  
Structure Space

Abstract The ABX-compounds MgCuP, BaCuP(As) and BaAgP(As) have been prepared and their structures determined. MgCuP crystallizes orthorhombically in an anti-PbCl2-structure (space group Pnma-D162h, a = 653.2(1) pm, b - 383.5(1) pm, c = 717.0(1) pm). The compounds BaCuP(As) and BaAgP(As) are isotypic and crystallize in a modified Ni2ln-structure (space group P63/mmc-D46h) with the lattice constants:BaCuP a = 423.9(1) pm, c = 900.6(2) pm,BaCuAs a = 437.2(1) pm, c = 907.3(2) pm,BaAgP a = 449.6(1) pm, c = 882.8(2) pm,BaAgAs a = 461.3(1 )pm, c = 889.6(1) pm.

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