scholarly journals Co-crystallization of an organic solid and a tetraaryladamantane at room temperature

2021 ◽  
Vol 17 ◽  
pp. 1476-1480
Author(s):  
Fabian Rami ◽  
Jan Nowak ◽  
Felix Krupp ◽  
Wolfgang Frey ◽  
Clemens Richert
Keyword(s):  
Crystal Lattice ◽  
Small Molecules ◽  
Crystal Structures ◽  
Structure Elucidation ◽  
Room Temperature ◽  
Slow Evaporation ◽  
Guest Molecules ◽  
Thermal Crystallization ◽  
Organic Solid

Tetraaryladamantanes have proven useful as chaperones for the co-crystallization of small molecules that do not readily crystallize by themselves. The co-crystals are often useful for structure elucidation. Usually, the small molecules are encapsulated in the crystal lattice of the aryladamantane that forms during rapid thermal crystallization. Thus far, co-crystallization has been limited to liquids as guest molecules. Here we report the co-crystal structures of phenol, which is solid at room temperature, with both 1,3,5,7-tetrakis(2,4-dimethoxyphenyl)adamantane (TDA) and 1,3,5,7-tetrakis(2,4-diethoxyphenyl)adamantane (TEO). The co-crystals were obtained from solutions in dichloromethane by slow evaporation or diffusion. The implications for generating other co-crystals of two solids are briefly discussed.

Distorted chiolite crystal structures of α-Na5M3F14 (M=Cr,Fe,Ga) studied by X-ray powder diffraction

2003 ◽  
Vol 18 (2) ◽  
pp. 128-134 ◽  
Author(s):  
A. Le Bail ◽  
A.-M. Mercier
Keyword(s):  
Crystal Structures ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Rietveld Refinements ◽  
Space Group ◽  
X Ray ◽  
Precise Characterization

The crystal structures of the chiolite-related room temperature phases α-Na5M3F14 (MIII=Cr,Fe,Ga) are determined. For all of them, the space group is P21/n, Z=2; a=10.5096(3) Å, b=7.2253(2) Å, c=7.2713(2) Å, β=90.6753(7)° (M=Cr); a=10.4342(7) Å, b=7.3418(6) Å, c=7.4023(6) Å, β=90.799(5)° (M=Fe), and a=10.4052(1) Å, b=7.2251(1) Å, c=7.2689(1), β=90.6640(4)° (M=Ga). Rietveld refinements produce final RF factors 0.036, 0.033, and 0.035, and RWP factors, 0.125, 0.116, and 0.096, for MIII=Cr, Fe, and Ga, respectively. The MF6 polyhedra in the defective isolated perovskite-like layers deviate very few from perfect octahedra. Subtle octahedra tiltings lead to the symmetry decrease from the P4/mnc space group adopted by the Na5Al3F14 chiolite aristotype to the P21/n space group adopted by the title series. Facile twinning precluded till now the precise characterization of these compounds.

Eu3+ Ion Luminescence Spectra from Lanthanide Sesquioxides Exhibiting Three Different Crystal Structures

1992 ◽  
Vol 46 (2) ◽  
pp. 273-276 ◽  
Author(s):  
G. Chen ◽  
R. G. Haire ◽  
J. R. Peterson
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Room Temperature ◽  
Luminescence Spectra ◽  
Spectral Splitting ◽  
The Eu

We have investigated the Eu3+ ion luminescence spectra from different host crystals of the lanthanide sesquioxides exhibiting either the A, B, or C form. The Eu3+ ion luminescence spectra from B-type Eu2O3 and from Eu3+-doped A-type La2O3 and C-type Lu2O3 were obtained at room temperature. It is suggested that the luminescence from f-f transitions in the Eu3+ ion can be used to determine the crystal structure, because the different Eu3+ ion site symmetries in the different crystal structures give rise to different characteristic spectral splitting patterns.

scholarly journals Crystal structure of the new hybrid material bis(1,4-diazoniabicyclo[2.2.2]octane) di-μ-chlorido-bis[tetrachloridobismuthate(III)] dihydrate

2015 ◽  
Vol 71 (11) ◽  
pp. 1384-1387
Author(s):  
Marwen Chouri ◽  
Habib Boughzala
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Hydrogen Bonds ◽  
Room Temperature ◽  
Molar Ratio ◽  
Water Molecules ◽  
Site Symmetry ◽  
Two Dimensional ◽  
Slow Evaporation ◽  
Solution Ph

The title compound bis(1,4-diazoniabicyclo[2.2.2]octane) di-μ-chlorido-bis[tetrachloridobismuthate(III)] dihydrate, (C6H14N2)2[Bi2Cl10]·2H2O, was obtained by slow evaporation at room temperature of a hydrochloric aqueous solution (pH = 1) containing bismuth(III) nitrate and 1,4-diazabicyclo[2.2.2]octane (DABCO) in a 1:2 molar ratio. The structure displays a two-dimensional arrangement parallel to (100) of isolated [Bi2Cl10]4−bioctahedra (site symmetry -1) separated by layers of organic 1,4-diazoniabicyclo[2.2.2]octane dications [(DABCOH2)2+] and water molecules. O—H...Cl, N—H...O and N—H...Cl hydrogen bonds lead to additional cohesion of the structure.

The crystal structures of solvent-free alkali-metal squarates from powder diffraction data

2005 ◽  
Vol 220 (11) ◽  
Author(s):  
Robert E. Dinnebier ◽  
Hanne Nuss ◽  
Martin Jansen
Keyword(s):  
High Resolution ◽  
Alkali Metal ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Room Temperature ◽  
Solvent Free ◽  
Crystallographic Data ◽  
Powder Diffraction Data ◽  
X Ray

AbstractThe crystal structures of solvent-free lithium, sodium, rubidium, and cesium squarates have been determined from high resolution synchrotron and X-ray laboratory powder patterns. Crystallographic data at room temperature of Li

Synthesis and aldol cyclotrimerization of 4,7-di-tert-butylacenaphthenone

2006 ◽  
Vol 84 (10) ◽  
pp. 1268-1272 ◽  
Author(s):  
Aaron W Amick ◽  
Keith S Griswold ◽  
Lawrence T Scott
Keyword(s):  
Key Words ◽  
Crystal Structures ◽  
Silica Gel ◽  
Room Temperature ◽  
Titanium Tetrachloride ◽  
X Ray ◽  
Synthetic Intermediates

An efficient gram scale synthesis of the previously unknown 4,7-di-tert-butylacenaphthenone (3b) is reported. The facile isomerization of epoxide 9b to ketone 3b occurs simply on stirring a solution of 9b with silica gel at room temperature. Aldol cyclotrimerization of 3b with titanium tetrachloride gives 2,5,8,11,14,17-hexa-tert-butylde cacyclene (1b) in 58% isolated yield. X-ray crystal structures have been obtained for the synthetic intermediates 4,7-di-tert-butylacenaphthene (2b) and 4,7-di-tert-butylacenaphthylene (8b).Key words: aromatic, decacyclene, hydrocarbon, nonalternant, polycyclic.

scholarly journals Supramolecular Frameworks Based on Rhenium Clusters Using the Synthons Approach

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2662
Author(s):  
Nathalie Audebrand ◽  
Antoine Demont ◽  
Racha El Osta ◽  
Yuri V. Mironov ◽  
Nikolay G. Naumov ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Crystal Structures ◽  
Ligand Exchange ◽  
Alkaline Earth ◽  
Room Temperature ◽  
Hydration Rate ◽  
Rhenium Cluster ◽  
New Compounds ◽  
Cluster Unit

The reaction of the K4[{Re6Si8}(OH)a6]·8H2O rhenium cluster salt with pyrazine (Pz) in aqueous solutions of alkaline or alkaline earth salts at 4 °C or at room temperature leads to apical ligand exchange and to the formation of five new compounds: [trans-{Re6Si8}(Pz)a2(OH)a2(H2O)a2] (1), [cis-{Re6Si8}(Pz)a2(OH)a2(H2O)a2] (2), (NO3)[cis-{Re6Si8}(Pz)a2(OH)a(H2O)a3](Pz)·3H2O (3), [Mg(H2O)6]0.5[cis-{Re6Si8}(Pz)a2(OH)a3(H2O)a]·8.5H2O (4), and K[cis-{Re6Si8}(Pz)a2(OH)a3(H2O)a]·8H2O (5). Their crystal structures are built up from trans- or cis-[{Re6Si8}(Pz)a2(OH)a4−x(H2O)ax]x−2 cluster units. The cohesions of the 3D supramolecular frameworks are based on stacking and H bonding, as well as on H3O2−bridges in the cases of (1), (2), (4), and (5) compounds, while (3) is built from stacking and H bonding only. This evidences that the nature of the synthons governing the cluster unit assembly is dependent on the hydration rate of the unit.

scholarly journals Radiation damage effects on protein conformation at room temperature and 100K

2014 ◽  
Vol 70 (a1) ◽  
pp. C344-C344
Author(s):  
Silvia Russi ◽  
Shawn Kann ◽  
Henry van den Bedem ◽  
Ana M. González
Keyword(s):  
Data Collection ◽  
Radiation Damage ◽  
Crystal Structures ◽  
Room Temperature ◽  
Relative Rate ◽  
Absorbed Dose ◽  
Conformational Ensemble ◽  
Data Sets ◽  
Cryogenic Temperatures ◽  
Full Data

Protein crystallography data collection at synchrotrons today is routinely carried out at cryogenic temperatures to mitigate radiation damage to the crystal. Although damage still takes place, at 100 K and below, the immobilization of free radicals increases the lifetime of the crystals by orders of magnitude. Increasingly, experiments are carried out at room temperature. The lack of adequate cryo-protectants, the induced lattice changes or internal disorders during the cooling process, and the convenience of collecting data directly from the crystallization plates, are some of the reasons. Moreover, recent studies have shown that flash-freezing affects the conformational ensemble of crystal structures [1], and can hide important functional mechanisms from observation [2]. While there has been a considerable amount of effort in studying radiation damage at cryo-temperatures, its effects at room temperature are still not well understood. We investigated the effects of data collection temperature on secondary local damage to the side chain and main chain from different proteins. Data were collected from crystals of thaumatin and lysozyme at 100 K and room temperature. To carefully control the total absorbed dose, full data sets at room temperature were assembled from a few diffraction images per crystal. Several data sets were collected at increasing levels of absorbed dose. Our analysis shows that while at cryogenic temperatures, radiation damage increases the conformational variability, _x0004_at room temperature it has the opposite effect_x0005_. We also observed that disulfide bonds appear to break up at a different relative rate at room temperature, perhaps because of a more active repair mechanism. Our analysis suggests that elevated conformational heterogeneity in crystal structures at room temperature is observed despite radiation damage, and not as a result thereof.

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