ChemInform Abstract: X-RAY PHOTOELECTRON SPECTROSCOPIC (X-P.E.S.) STUDIES ON IN SITU PHOTOINDUCED DECOMPOSITION OF INORGANIC MOLECULAR IONS. PART 2. NA(CLOX) SYSTEM- MECHANISTIC (X = 3,4) AND VARIABLE-TEMPERATURE (X = 3) INVESTIGATIONS

1978 ◽  
Vol 9 (45) ◽  
Author(s):  
R. G. COPPERTHWAITE ◽  
J. LLOYD
Keyword(s):  
Variable Temperature ◽  
Molecular Ions ◽  
X Ray

Molecular motions of a tetraphenylethylene-derived AIEgen directly monitored through in situ variable temperature single crystal X-ray diffraction

CrystEngComm ◽  
2021 ◽  
Author(s):  
Wei Meng ◽  
Lin Du ◽  
Lin Sun ◽  
Lian Zhou ◽  
Xiaopeng Xuan ◽  
...  
Keyword(s):  
Single Crystal ◽  
Phenyl Ring ◽  
Functional Group ◽  
Variable Temperature ◽  
Molecular Motions ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Conformation Changes

One organic functional group was introduced to distinguish the four phenyl ring of tetraphenylethylene, and the In situ temperature-dependent crystal structures were determined to exhibit the conformation changes of tert-butyl...

scholarly journals High-temperature in situ crystallographic observation of reversible gas sorption in impermeable organic cages

2015 ◽  
Vol 112 (46) ◽  
pp. 14156-14161 ◽  
Author(s):  
Seung Bin Baek ◽  
Dohyun Moon ◽  
Robert Graf ◽  
Woo Jong Cho ◽  
Sung Woo Park ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Temperatures ◽  
Direct Detection ◽  
Variable Temperature ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dynamic Motion

Crystallographic observation of adsorbed gas molecules is a highly difficult task due to their rapid motion. Here, we report the in situ single-crystal and synchrotron powder X-ray observations of reversible CO2 sorption processes in an apparently nonporous organic crystal under varying pressures at high temperatures. The host material is formed by hydrogen bond network between 1,3,5-tris-(4-carboxyphenyl)benzene (H3BTB) and N,N-dimethylformamide (DMF) and by π–π stacking between the H3BTB moieties. The material can be viewed as a well-ordered array of cages, which are tight packed with each other so that the cages are inaccessible from outside. Thus, the host is practically nonporous. Despite the absence of permanent pathways connecting the empty cages, they are permeable to CO2 at high temperatures due to thermally activated molecular gating, and the weakly confined CO2 molecules in the cages allow direct detection by in situ single-crystal X-ray diffraction at 323 K. Variable-temperature in situ synchrotron powder X-ray diffraction studies also show that the CO2 sorption is reversible and driven by temperature increase. Solid-state magic angle spinning NMR defines the interactions of CO2 with the organic framework and dynamic motion of CO2 in cages. The reversible sorption is attributed to the dynamic motion of the DMF molecules combined with the axial motions/angular fluctuations of CO2 (a series of transient opening/closing of compartments enabling CO2 molecule passage), as revealed from NMR and simulations. This temperature-driven transient molecular gating can store gaseous molecules in ordered arrays toward unique collective properties and release them for ready use.

Versatile variable temperature insert at the DEIMOS beamline forin situelectrical transport measurements

2016 ◽  
Vol 23 (3) ◽  
pp. 652-657 ◽  
Author(s):  
L. Joly ◽  
B. Muller ◽  
E. Sternitzky ◽  
J.-G. Faullumel ◽  
A. Boulard ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Electrical Transport ◽  
Tunnel Junctions ◽  
Variable Temperature ◽  
Electronic Devices ◽  
X Ray ◽  
In Operando ◽  
X Ray Absorption ◽  
Multifunctional Properties

The design and the first experiments are described of a versatile cryogenic insert used for its electrical transport capabilities. The insert is designed for the cryomagnet installed on the DEIMOS beamline at the SOLEIL synchrotron dedicated to magnetic characterizations through X-ray absorption spectroscopy (XAS) measurements. This development was spurred by the multifunctional properties of novel materials such as multiferroics, in which, for example, the magnetic and electrical orders are intertwined and may be probed using XAS. The insert thus enables XAS toin situprobe this interplay. The implementation of redundant wiring and careful shielding also enables studies on operating electronic devices. Measurements on magnetic tunnel junctions illustrate the potential of the equipment toward XAS studies ofin operandoelectronic devices.

Tautomeric polymorphism of the neuroactive inhibitor kynurenic acid

2019 ◽  
Vol 75 (6) ◽  
pp. 793-805
Author(s):  
Dorota Pogoda ◽  
Jan Janczak ◽  
Sylwia Pawlak ◽  
Michael Zaworotko ◽  
Veneta Videnova-Adrabinska
Keyword(s):  
Solid State ◽  
Kynurenic Acid ◽  
Variable Temperature ◽  
Neurological Diseases ◽  
Crystal Form ◽  
Phase Behaviour ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

Kynurenic acid (KYN; systematic name: 4-hydroxyquinoline-2-carboxylic acid, C10H7NO3) displays a therapeutic effect in the treatment of some neurological diseases and is used as a broad-spectrum neuroprotective agent. However, it is understudied with respect to its solid-state chemistry and only one crystal form (α-KYN·H2O) has been reported up to now. Therefore, an attempt to synthesize alternative solid-state forms of KYN was undertaken and six new species were obtained: five solvates and one salt. One of them is a new polymorph, β-KYN·H2O, of the already known KYN monohydrate. All crystal species were further studied by single-crystal and powder X-ray diffraction, thermal and spectroscopic methods. In addition to the above methods, differential scanning calorimetry (DSC), in-situ variable-temperature powder X-ray diffraction and Raman microscopy were applied to characterize the phase behaviour of the new forms. All the compounds display a zwitterionic form of KYN and two different enol–keto tautomers are observed depending on the crystallization solvent used.

Synthesis and Molecular Structures of 2-Trimethylsilyl-, 2-Trimethylgermyl-, and 2-Trimethylstannyl-pyridines

1999 ◽  
Vol 54 (1) ◽  
pp. 13-17 ◽  
Author(s):  
Frank Riedmiller ◽  
Alexander Jockisch ◽  
Hubert Schmidbaur
Keyword(s):  
Quantum Chemical ◽  
Crystal And Molecular Structure ◽  
Variable Temperature ◽  
Intrinsic Property ◽  
Molecular Structures ◽  
Grignard Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nitrogen Heteroatom

5-Methyl-2-trimethylsilyl-pyridine (1) has recently been prepared via the “in situ” Grignard reaction of 1-bromo-5-methyl-pyridine with magnesium and trimethylchlorosilane in refluxing tetrahydrofuran (thf) and structurally characterized. 2-Trimethylgermyl- (2) and 2- trimethylstannyl-pyridine (3) were now obtained from 2-bromo-pyridine through metallation (with n-BuLi) and treatment of the intermediates with Me3GeBr and Me3SnCl, respectively, in diethylether/ thf at -70°C. The crystal and molecular structure of compound 2 has been determined by low temperature (in situ) single crystal X-ray diffraction methods. There is a significant bending of the Me3Ge substituent towards the nitrogen heteroatom [Ge-C-N = 114.7(2)°]. This phenomenon is known from previous studies of the silicon analogue 1 to be not due to intramolecular (peripheral) Si/Ge←N coordination, but to be rather an intrinsic property of the heteroarene skeleton, as also confirmed by quantum-chemical calculations. Furthermore, there is no evidence for intermolecular coordination in the crystals. Such interactions could also be ruled out for the solution state of 2 and 3 through variable temperature multinuclear NMR investigations.

Variable temperature in situ X-ray diffraction study of mechanically activated synthesis of calcium titanate, CaTiO3

2003 ◽  
Vol 38 (7) ◽  
pp. 1203-1213 ◽  
Author(s):  
Ivana Radosavljevic Evans ◽  
Judith A.K. Howard ◽  
Tatjana Sreckovic ◽  
Momcilo M. Ristic
Keyword(s):  
Diffraction Study ◽  
Variable Temperature ◽  
Calcium Titanate ◽  
X Ray Diffraction ◽  
X Ray

Formation mechanism of spinel LiTi2O4 prepared by carbon thermal reduction reaction

RSC Advances ◽  
2015 ◽  
Vol 5 (118) ◽  
pp. 97720-97723 ◽  
Author(s):  
Guijun Yang ◽  
Jianwen Yang ◽  
Lingzhi Zhang
Keyword(s):  
Formation Mechanism ◽  
Variable Temperature ◽  
Thermal Reduction ◽  
Reduction Reaction ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
System P

The formation mechanism of LiTi2O4 is investigated by in situ variable temperature X-ray diffraction and thermal gravimetric analysis/differential scanning calorimetry system.

A portable ultrahigh-vacuum system for advanced synchrotron radiation studies of thin films and nanostructures: EuSi2nano-islands

2015 ◽  
Vol 22 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Shyjumon Ibrahimkutty ◽  
Anja Seiler ◽  
Tim Prüßmann ◽  
Tonya Vitova ◽  
Ramu Pradip ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Variable Temperature ◽  
Ultrahigh Vacuum ◽  
Vacuum System ◽  
X Ray ◽  
X Ray Scattering ◽  
New Instrument ◽  
Institute Of Technology ◽  
Ray Scattering

A portable ultrahigh-vacuum system optimized forin situvariable-temperature X-ray scattering and spectroscopy experiments at synchrotron radiation beamlines was constructed and brought into operation at the synchrotron radiation facility ANKA of the Karlsruhe Institute of Technology, Germany. Here the main features of the new instrument are described and its capabilities demonstrated. The surface morphology, structure and stoichiometry of EuSi2nano-islands are determined byin situgrazing-incidence small-angle X-ray scattering and X-ray absorption spectroscopy. A size reduction of about a factor of two of the nano-islands due to silicide decomposition and Eu desorption is observed after sample annealing at 1270 K for 30 min.

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