On the crystal structure of heterogeneous catalysts at reaction-conditions: ?in-situ? X-ray powder diffraction

1994 ◽  
Vol 349 (1-3) ◽  
pp. 247-249 ◽  
Author(s):  
B. Herzog ◽  
T. Ilkenhans ◽  
R. Schl�gl
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Heterogeneous Catalysts ◽  
Reaction Conditions ◽  
X Ray

scholarly journals Investigation of reaction conditions on synthesis of steroidal bromohydrin and structural analysis of novel 6α-brom-5β-hydroxy derivative

2018 ◽  
Vol 16 (2) ◽  
pp. 219-228
Author(s):  
Ivana Kuzminac ◽  
Olivera Klisuric ◽  
Andrea Nikolic ◽  
Marija Sakac
Keyword(s):  
Crystal Structure ◽  
Perchloric Acid ◽  
Crystal Structure Analysis ◽  
Hydroxy Derivative ◽  
Reaction Products ◽  
Reaction Conditions ◽  
X Ray ◽  
Hypobromous Acid ◽  
Series Of Experiments

Reaction conditions variation and its influence on the reaction of 3?- acetoxy-17-oxa-17a-homoandrost-5-en-16-one with in situ generated hypobromous acid was investigated. Hypobromous acid was generated from N-bromoacetamide or Nbromosuccinimide and perchloric acid, and as solvent dioxane, dimethoxyethane or tetrahydrofuran were used. After a series of experiments, it was determined that the number of the reaction products depends on the reagent used, solvents, perchloric acid concentration and the presence/absence of daylight. It has also been found that the yields of certain compounds depend also on the reaction time and temperature. 6?-Bromo-5?- hydroxy derivate is obtained by usage of NBA and 0.28 M perchloric acid in dioxane on daylight. Its structure was confirmed by NMR and X-ray crystal structure analysis.

scholarly journals Formation and structure of the first metal complexes comprising amidinoguanidinate ligands

2016 ◽  
Vol 72 (11) ◽  
pp. 1526-1531 ◽  
Author(s):  
Farid M. Sroor ◽  
Phil Liebing ◽  
Cristian G. Hrib ◽  
Daniel Gräsing ◽  
Liane Hilfert ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Metal Complexes ◽  
Solid State Reaction ◽  
The Novel ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
X Ray

The first metal complexes comprising amidinoguanidinate ligands have been prepared and structurally characterized, namely bis[μ-N,N′,N′′,N′′′-tetraisopropyl-1-(1-butylamidinato)guanidinato-κ3N1,N2:N2]bis[(tetrahydrofuran)lithium], [Li2(C18H37N4)2(C4H8O)2], (2), and [bis(tetrahydrofuran)lithium]-di-μ-chlorido-{(N,N′-dicyclohexyl-1-butylamidinato-κ2N1,N2)[N,N′,N′′,N′′′-tetracyclohexyl-1-(1-butylamidinato)guanidinato-κ2N1,N2]holmate(III)}, [HoLiCl2(C4H8O)2(C17H31N2)(C30H53N4)], (3). The novel lithium amidinoguanidinate precursors Li[nBuC(=NR)(NR)C(NR)2] [1:R= Cy (cyclohexyl),2:R=iPr) were obtained by treatment ofN,N′-diorganocarbodiimides,R—N=C=N—R(R=iPr, Cy), with 0.5 equivalents ofn-butyllithium under well-defined reaction conditions. An X-ray diffraction study of2revealed a ladder-type dimeric structure in the solid state. Reaction of anhydrous holmium(III) chloride within situ-prepared2afforded the unexpected holmium `ate' complex [nBuC(=NCy)(NCy)C(NCy)2]Ho[nBuC(NCy)2](μ-Cl)2Li(THF)2(3) in 71% yield. An X-ray crystal structure determination of3showed that this complex contains both an amidinate ligand and the new amidinoguanidinate ligand.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

Monitoring Polymer-Assisted Mechanochemical Cocrystallisation Through in Situ X-Ray Powder Diffraction

2020 ◽  
Author(s):  
Luzia S. Germann ◽  
Sebastian T. Emmerling ◽  
Manuel Wilke ◽  
Robert E. Dinnebier ◽  
Mariarosa Moneghini ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Powder Diffraction ◽  
Reaction Rate ◽  
Polymer Additives ◽  
Time Resolved ◽  
X Ray

Time-resolved mechanochemical cocrystallisation studies have so-far focused solely on neat and liquid-assisted grinding. Here, we report the monitoring of polymer-assisted grinding reactions using <i>in situ</i> X-ray powder diffraction, revealing that reaction rate is almost double compared to neat grinding and independent of the molecular weight and amount of used polymer additives.<br>

scholarly journals Crystal structure of pimecrolimus Form B, C43H68ClNO11

2021 ◽  
Vol 36 (1) ◽  
pp. 35-42
Author(s):  
Shivang Bhaskar ◽  
Joseph T. Golab ◽  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Density Functional ◽  
Van Der Waals Interactions ◽  
Powder Diffraction File ◽  
X Ray ◽  
Weak Intermolecular Interactions ◽  
Significant Difference ◽  
Atomic Coordinates ◽  
Solid State Conformation

The crystal structure of pimecrolimus Form B has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Pimecrolimus crystallizes in the space group P21 (#4) with a = 15.28864(7), b = 13.31111(4), c = 10.95529(5) Å, β = 96.1542(3)°, V = 2216.649(9) Å3, and Z = 2. Although there are an intramolecular six-ring hydrogen bond and some larger chain and ring patterns, the crystal structure is dominated by van der Waals interactions. There is a significant difference between the conformation of the Rietveld-refined and the DFT-optimized structures in one portion of the macrocyclic ring. Although weak, intermolecular interactions are apparently important in determining the solid-state conformation. The powder pattern is included in the Powder Diffraction File™ (PDF®) as entry 00-066-1619. This study provides the atomic coordinates to be added to the PDF entry.

The Crystal Structure of Sb0.92V0.92O4, Determined by Neutron and Dual Wavelength X-Ray Powder Diffraction

1993 ◽  
Vol 102 (2) ◽  
pp. 340-348 ◽  
Author(s):  
Staffan Hansen ◽  
Kenny Ståhl ◽  
Roland Nilsson ◽  
Arne Andersson
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Dual Wavelength ◽  
X Ray

Crystal structure of the anticancer drug carmustine determined by X-ray powder diffraction

2021 ◽  
pp. 1-3
Author(s):  
Carina Schlesinger ◽  
Edith Alig ◽  
Martin U. Schmidt
Keyword(s):  
Crystal Structure ◽  
Anticancer Drug ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Powder Diffraction Data ◽  
Orthorhombic Space Group ◽  
Commercial Sample ◽  
One Dimensional ◽  
X Ray ◽  
Hydrogen Bond Pattern

The structure of the anticancer drug carmustine (1,3-bis(2-chloroethyl)-1-nitrosourea, C5H9Cl2N3O2) was successfully determined from laboratory X-ray powder diffraction data recorded at 278 K and at 153 K. Carmustine crystallizes in the orthorhombic space group P212121 with Z = 4. The lattice parameters are a = 19.6935(2) Å, b = 9.8338(14) Å, c = 4.63542(6) Å, V = 897.71(2) ų at 153 K, and a = 19.8522(2) Å, b = 9.8843(15) Å, c = 4.69793(6) Å, V = 921.85(2) ų at 278 K. The Rietveld fits are very good, with low R-values and smooth difference curves of calculated and experimental powder data. The molecules form a one-dimensional hydrogen bond pattern. At room temperature, the investigated commercial sample of carmustine was amorphous.

Crystal structure of ziprasidone hydrochloride monohydrate, C21H22Cl2N4OS(H2O)

2015 ◽  
Vol 30 (3) ◽  
pp. 192-198
Author(s):  
James A. Kaduk ◽  
Kai Zhong ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Powder Diffraction ◽  
Density Functional ◽  
Minimum Energy ◽  
Strong Hydrogen Bond ◽  
Powder Diffraction File ◽  
X Ray ◽  
Hydrochloride Monohydrate ◽  
Positively Charged

The crystal structure of ziprasidone hydrochloride monohydrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Ziprasidone hydrochloride monohydrate crystallizes in space group P-1 (#2) with a = 7.250 10(3), b = 10.986 66(8), c = 14.071 87(14) Å, α = 83.4310(4), β = 80.5931(6), γ = 87.1437(6)°, V = 1098.00(1) Å3, and Z = 2. The ziprasidone conformation in the solid state is very close to the minimum energy conformation. The positively-charged nitrogen in the ziprasidone makes a strong hydrogen bond with the chloride anion. The water molecule makes two weaker bonds to the chloride, and acts as an acceptor in an N–H⋯O hydrogen bond. The powder pattern is included in the Powder Diffraction File™ as entry 00-064-1492.

Crystal structure of oxybutynin hydrochloride hemihydrate, C22H32NO3Cl(H2O)0.5

2019 ◽  
Vol 34 (1) ◽  
pp. 50-58
Author(s):  
James A. Kaduk ◽  
Nicholas C. Boaz ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Powder Diffraction ◽  
Density Functional ◽  
Hydroxyl Group ◽  
Layered Crystal ◽  
Powder Diffraction File ◽  
X Ray ◽  
Layered Crystal Structure ◽  
Oxybutynin Hydrochloride

The crystal structure of oxybutynin hydrochloride hemihydrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Oxybutynin hydrochloride hemihydrate crystallizes in space group I2/a (#15) with a = 14.57266(8), b = 8.18550(6), c = 37.16842(26) Å, β = 91.8708(4)°, V = 4421.25(7) Å3, and Z = 8. The compound exhibits X-ray-induced photoreduction of the triple bond. Prominent in the layered crystal structure is the N–H⋅⋅⋅Cl hydrogen bond between the cation and anion, as well as O–H⋅⋅⋅Cl hydrogen bonds from the water molecule and hydroxyl group of the oxybutynin cation. C–H⋅⋅⋅Cl hydrogen bonds also contribute to the crystal energy, and help determine the conformation of the cation. The powder pattern is included in the Powder Diffraction File™ as entry 00-068-1305.

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