Monitoring structural transformations in crystals. 8. Monitoring molecules and a reaction center during a solid-state Yang photocyclization

2006 ◽  
Vol 62 (1) ◽  
pp. 128-134 ◽  
Author(s):  
Ilona Turowska-Tyrk ◽  
Elżbieta Trzop ◽  
John R. Scheffer ◽  
Shuang Chen
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Photochemical Reaction ◽  
Structural Changes ◽  
Structural Transformations ◽  
Reaction Progress ◽  
X Ray ◽  
Intermolecular Reactions ◽  
Reactant Molecule ◽  
Cyclobutane Ring

Structural changes taking place in a crystal during an intramolecular photochemical reaction [the Yang photocyclization of the α-methylbenzylamine salt with 1-(4-carboxybenzoyl)-1-methyladamantane] were monitored step-by-step using X-ray structure analysis. This is the first example of such a study carried out for an intramolecular photochemical reaction. During the photoreaction, both the reactant and product molecules change their orientation, but the reactant changes more rapidly after the reaction is about 80% complete. The distance between directly reacting atoms in the reactant molecule is almost constant until about 80% reaction progress and afterwards decreases. The torsion angle defined by the reactant atoms that form the cyclobutane ring also changes in the final stages of the photoreaction. These phenomena are explained in terms of the influence of many product molecules upon a small number of reacting molecules. The adamantane portion shifts more than the remaining part of the anionic reactant species during the reaction, which is explained in terms of hydrogen bonding. The structural changes are accompanied by changes in the cell constants. The results obtained in the present study are compared with analogous results published for intermolecular reactions.

Monitoring structural transformations in crystals. 11. Yang photocyclizations – one type of reaction, but diversity of structural changes

2007 ◽  
Vol 63 (6) ◽  
pp. 933-940 ◽  
Author(s):  
Ilona Turowska-Tyrk ◽  
Julia Bąkowicz ◽  
John R. Scheffer
Keyword(s):  
Hydrogen Bonds ◽  
Photochemical Reaction ◽  
Structural Changes ◽  
Structural Transformations ◽  
Geometrical Parameters ◽  
Reaction Centre ◽  
Carboxylate Group ◽  
Molecular Fragments ◽  
Reaction Progress ◽  
X Ray

Structural changes proceeding in a crystal during the Yang photocyclization of the salt 6,6-diethyl-5-oxo-5,6,7,8-tetrahydronaphthalene-2-carboxylate with (1S)-1-(4-methylphenyl)ethylamine were monitored by means of X-ray structure analysis. The course of the photoreaction was evaluated on the basis of the geometrical parameters for the pure reactant crystal. Variations in the cell constants, the product content, the geometry of the reaction centre, the orientation of molecular fragments and the geometry of hydrogen bonds were described and analyzed. It was found that the cell volume increased until 56% product content and decreased thereafter. The distance between the directly reacting C atoms was constant, ∼ 3.0 Å, until ∼ 75% reaction progress. Analysis of the distance between atoms that would participate in the formation of the second (unobserved) enantiomorph excluded the formation of such an isomer. Molecular fragments varied their orientation during the photoreaction, and the largest change was observed for the carboxylate group despite its participation in strong hydrogen bonds. The geometry of the hydrogen bonds changed during the photoreaction. The largest change was 0.17 Å for the D...A distance and 13° for the D—H...A angle. A comparison of the intra- and intermolecular parameters for the studied salt with data for other compounds undergoing the Yang photocyclization in crystals revealed a diversity of structural changes brought about by this type of photochemical reaction.

scholarly journals In situ X-ray diffraction computed tomography studies examining the thermal and chemical stabilities of working Ba0.5Sr0.5Co0.8Fe0.2O3−δ membranes during oxidative coupling of methane

2020 ◽  
Vol 22 (34) ◽  
pp. 18964-18975
Author(s):  
Dorota Matras ◽  
Antonis Vamvakeros ◽  
Simon D. M. Jacques ◽  
Vesna Middelkoop ◽  
Gavin Vaughan ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Solid State ◽  
Oxidative Coupling ◽  
Structural Changes ◽  
Oxidative Coupling Of Methane ◽  
Membrane Reactors ◽  
Solid State Chemistry ◽  
X Ray Diffraction ◽  
X Ray

In situ XRD-CT and post-reaction SEM/EDX were used to study the solid-state chemistry and structural changes of Ba0.5Sr0.5Co0.8Fe0.2O3−δ membrane reactors during the oxidative coupling of methane reaction.

ChemInform Abstract: Hydrogen Bonding and the Structure of Substituted Quinoxalines: Solid- State NMR and Single-Crystal X-Ray Diffraction Studies.

ChemInform ◽  
2010 ◽  
Vol 24 (25) ◽  
pp. no-no
Author(s):  
K. WOZNIAK ◽  
T. M. KRYGOWSKI ◽  
E. GRECH ◽  
W. KOLODZIEJSKI ◽  
J. KLINOWSKI
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Single Crystal ◽  
Solid State Nmr ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals A multinuclear solid state NMR, density functional theory and X-Ray diffraction study of hydrogen bonding in Group I hydrogen dibenzoates

CrystEngComm ◽  
2013 ◽  
Vol 15 (43) ◽  
pp. 8823 ◽  
Author(s):  
Gregory J. Rees ◽  
Stephen P. Day ◽  
Alberth Lari ◽  
Andrew P. Howes ◽  
Dinu Iuga ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bonding ◽  
Solid State ◽  
Diffraction Study ◽  
Solid State Nmr ◽  
Density Functional ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Group I

scholarly journals Redetermination of ammonium metavanadate

IUCrData ◽  
2018 ◽  
Vol 3 (8) ◽  
Author(s):  
Aarón Pérez-Benítez ◽  
Sylvain Bernès
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Solid State ◽  
Single Crystal ◽  
Structural Data ◽  
Ammonium Cation ◽  
Ammonium Metavanadate ◽  
Starting Material ◽  
X Ray ◽  
Hydrogen Bonding Interactions

The crystal structure of ammonium metavanadate, NH4VO3, a compound widely used as a starting material for the synthesis of vanadium and polyoxidovanadate compounds, had been determined twice using single-crystal X-ray data [Syneček & Hanic (1954). Czech. J. Phys. 4, 120–129 (Weissenberg data); Hawthorne & Calvo (1977). J. Solid State Chem. 22, 157–170 (four-circle diffractometer data)]. Its structure is now redetermined at higher resolution using Ag Kα radiation, and the result is compared with the former refinements. Structural data for the polymeric [VO3]∞ chain remain unchanged, while more accurate parameters are obtained for the ammonium cation, improving the description of hydrogen-bonding interactions in the crystal structure.

scholarly journals Hydrates and polymorphs of lead squarate Pb(C4O4): Structural transformations studied by in situ X-ray powder diffraction and solid state NMR

Polyhedron ◽  
2019 ◽  
Vol 164 ◽  
pp. 123-131 ◽  
Author(s):  
Thierry Bataille ◽  
Amira Bouhali ◽  
Cassandre Kouvatas ◽  
Chahrazed Trifa ◽  
Nathalie Audebrand ◽  
...  
Keyword(s):  
Solid State ◽  
Powder Diffraction ◽  
Solid State Nmr ◽  
Structural Transformations ◽  
X Ray

scholarly journals Thermal Reactivity in Metal Organic Materials (MOMs): From Single-Crystal-to-Single-Crystal Reactions and Beyond

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4088
Author(s):  
Javier Martí-Rujas
Keyword(s):  
Solid State ◽  
Single Crystal ◽  
Organic Materials ◽  
Structural Transformations ◽  
Atomic Motion ◽  
X Ray Diffraction ◽  
Thermally Induced ◽  
X Ray ◽  
Thermal Reactivity ◽  
Metal Organic

Thermal treatment is important in the solid-state chemistry of metal organic materials (MOMs) because it can create unexpected new structures with unique properties and applications that otherwise in the solution state are very difficult or impossible to achieve. Additionally, high-temperature solid-state reactivity provide insights to better understand chemical processes taking place in the solid-state. This review article describes relevant thermally induced solid-state reactions in metal organic materials, which include metal organic frameworks (MOFs)/coordination polymers (CPs), and second coordination sphere adducts (SSCs). High temperature solid-state reactivity can occur in a single-crystal-to-single crystal manner (SCSC) usually for cases where there is small atomic motion, allowing full structural characterization by single crystal X-ray diffraction (SC-XRD) analysis. However, for the cases in which the structural transformations are severe, often the crystallinity of the metal-organic material is damaged, and this happens in a crystal-to-polycrystalline manner. For such cases, in the absence of suitable single crystals, structural characterization has to be carried out using ab initio powder X-ray diffraction analysis or pair distribution function (PDF) analysis when the product is amorphous. In this article, relevant thermally induced SCSC reactions and crystal-to-polycrystalline reactions in MOMs that involve significant structural transformations as a result of the molecular/atomic motion are described. Thermal reactivity focusing on cleavage and formation of coordination and covalent bonds, crystalline-to-amorphous-to-crystalline transformations, host–guest behavior and dehydrochlorination reactions in MOFs and SSCs will be discussed.

X-ray study of the pseudopolymorphism of the azithromycin monohydrate

2003 ◽  
Vol 218 (10) ◽  
Author(s):  
J. M. Montejo-Bernardo ◽  
Santiago García-Grande ◽  
M. S. Bayod-Jasanada ◽  
L. Lavona-Díaz ◽  
I. Llorente
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Single Crystal ◽  
Powder Diffraction ◽  
Chemical Compositions ◽  
X Ray ◽  
Large Size ◽  
Similar Chemical ◽  
Solid State Conformation ◽  
State Composition

AbstractA combination of X-ray powder diffraction and single crystal studies on azithomycin pseudopolymorphs give the precise solid state composition of all monohydrate pseudopolymorphs reported. According to the X-ray results the four monohydrates of azithromycin studied have the same crystallographic parameters. Furthermore, the analysis of the relative intensities from the powder patterns points to very similar chemical compositions and crystal structures. This result has been confirmed by the single crystal studies. The single crystal studies show that the solid state conformation of the azithromycin molecules is affected by the presence of solvents. The solvent methanol molecules were found disordered probably due to the existence of many positions where the hydrogen bonding is favoured and the large size of the available space to host the solvents.

Structure and hydrogen bonding in 2,4-dihydroxybenzoic acid at 90, 100, 110 and 150 K; a theoretical and single-crystal X-ray diffraction study

2007 ◽  
Vol 63 (2) ◽  
pp. 303-308 ◽  
Author(s):  
Andrew Parkin ◽  
Martin Adam ◽  
Richard I. Cooper ◽  
Derek S. Middlemiss ◽  
Chick C. Wilson
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Hydrogen Bonds ◽  
X Ray Diffraction ◽  
Dihydroxybenzoic Acid ◽  
X Ray ◽  
Hydrogen Bond System ◽  
Proton Disorder ◽  
Intramolecular Hydrogen ◽  
Carboxylic Acid Dimer

A new polymorph of 2,4-dihydroxybenzoic acid is reported. The structure was characterized by multiple-temperature X-ray diffraction and solid-state DFT computations. The material shows a geometric pattern of hydrogen bonding consistent with cooperativity between the intermolecular carboxylic acid dimer and intramolecular hydrogen bonds. The presence of proton disorder within this hydrogen-bond system, which would support such a cooperative model, was not fully ruled out by the initial X-ray studies. However, solid-state calculations on the three possible end-point tautomers indicate that the dominant crystallographically observed configuration is substantially lower in energy than the other tautomers (by at least 9 kJ mol−1), indicating that no disorder should be expected. It is therefore concluded that no disorder is observed either in the intra- or intermolecular hydrogen bonds of the title compound and that the cooperativity between the hydrogen bonds is not present within the temperature range studied.

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