Experimental and Solid-State Computational Study of Structural and Dynamic Properties in the Equilibrium Form of Temazepam

2014 ◽  
Vol 118 (24) ◽  
pp. 6670-6679 ◽  
Author(s):  
Aleksandra Pajzderska ◽  
Kacper Drużbicki ◽  
Miguel A. Gonzalez ◽  
Jacek Jenczyk ◽  
Barbara Peplińska ◽  
...  
Keyword(s):  
Solid State ◽  
Computational Study ◽  
Dynamic Properties ◽  
Equilibrium Form

scholarly journals Use of Solid-State NMR Spectroscopy for the Characterization of Molecular Structure and Dynamics in Solid Polymer and Hybrid Electrolytes

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1207
Author(s):  
Gabrielle Foran ◽  
Nina Verdier ◽  
David Lepage ◽  
Cédric Malveau ◽  
Nicolas Dupré ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Pulse Sequence ◽  
Dynamic Properties ◽  
Double Resonance ◽  
Solid Polymer ◽  
Pulse Field ◽  
Solid State Nmr Spectroscopy

Solid-state NMR spectroscopy is an established experimental technique which is used for the characterization of structural and dynamic properties of materials in their native state. Many types of solid-state NMR experiments have been used to characterize both lithium-based and sodium-based solid polymer and polymer–ceramic hybrid electrolyte materials. This review describes several solid-state NMR experiments that are commonly employed in the analysis of these systems: pulse field gradient NMR, electrophoretic NMR, variable temperature T1 relaxation, T2 relaxation and linewidth analysis, exchange spectroscopy, cross polarization, Rotational Echo Double Resonance, and isotope enrichment. In this review, each technique is introduced with a short description of the pulse sequence, and examples of experiments that have been performed in real solid-state polymer and/or hybrid electrolyte systems are provided. The results and conclusions of these experiments are discussed to inform readers of the strengths and weaknesses of each technique when applied to polymer and hybrid electrolyte systems. It is anticipated that this review may be used to aid in the selection of solid-state NMR experiments for the analysis of these systems.

scholarly journals Correction: Dynamic properties of dipeptidyl peptidase III from Bacteroides thetaiotaomicron and the structural basis for its substrate specificity – a computational study

2017 ◽  
Vol 13 (12) ◽  
pp. 2729-2730
Author(s):  
M. Tomin ◽  
S. Tomić
Keyword(s):  
Substrate Specificity ◽  
Computational Study ◽  
Dynamic Properties ◽  
Dipeptidyl Peptidase ◽  
Structural Basis ◽  
Bacteroides Thetaiotaomicron

Correction for ‘Dynamic properties of dipeptidyl peptidase III from Bacteroides thetaiotaomicron and the structural basis for its substrate specificity – a computational study’ by M. Tomin et al., Mol. BioSyst., 2017, 13, 2407–2417.

Are the amide bonds in N-acyl imidazoles twisted? A combined solid-state 17O NMR, crystallographic, and computational study

2015 ◽  
Vol 93 (4) ◽  
pp. 451-458 ◽  
Author(s):  
Xianqi Kong ◽  
Aaron Tang ◽  
Ruiyao Wang ◽  
Eric Ye ◽  
Victor Terskikh ◽  
...  
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Crystal Structures ◽  
Computational Study ◽  
Chemical Shifts ◽  
Amide Bond ◽  
Chemical Shift Tensors ◽  
Amide Bonds ◽  
Bond Rotation ◽  
Quadrupole Coupling

We report synthesis of 17O-labeling and solid-state 17O NMR measurements of three N-acyl imidazoles of the type R-C(17O)-Im: R = p-methoxycinnamoyl (MCA-Im), R = 4-(dimethylamino)benzoyl (DAB-Im), and R = 2,4,6-trimethylbenzoyl (TMB-Im). Solid-state 17O NMR experiments allowed us to determine for the first time the 17O quadrupole coupling and chemical shift tensors in this class of organic compounds. We also determined the crystal structures of these compounds using single-crystal X-ray diffraction. The crystal structures show that, while the C(O)–N amide bond in DAB-Im exhibits a small twist, those in MCA-Im and TMB-Im are essentially planar. We found that, in these N-acyl imidazoles, the 17O quadrupole coupling and chemical shift tensors depend critically on the torsion angle between the conjugated acyl group and the C(O)–N amide plane. The computational results from a plane-wave DFT approach, which takes into consideration the entire crystal lattice, are in excellent agreement with the experimental solid-state 17O NMR results. Quantum chemical computations also show that the dependence of 17O NMR parameters on the Ar–C(O) bond rotation is very similar to that previously observed for the C(O)–N bond rotation in twisted amides. We conclude that one should be cautious in linking the observed NMR chemical shifts only to the twist of the C(O)–N amide bond.

scholarly journals Thermodynamics of the Atomic Distribution in Pt3Pd2, Pt2Pd3 and their Corresponding (111) Surfaces

2021 ◽  
Vol 74 ◽  
Author(s):  
Kyle Meerholz ◽  
David Santos-Carballal ◽  
Umberto Terranova ◽  
Anzel Falch ◽  
Cornelia G.C.E. van Sittert ◽  
...  
Keyword(s):  
Solid State ◽  
Bimetallic Catalysts ◽  
Computational Study ◽  
Interatomic Potentials ◽  
Site Occupation ◽  
Surface Energies ◽  
General Utility ◽  
Production Of Hydrogen ◽  
Surface Models ◽  
State Models

ABSTRACT In this study, we have developed solid-state models of platinum and palladium bimetallic catalysts, Pt3Pd2 and Pt2Pd3, which are rapidly thermally annealed at 800 °C. These models were constructed by determining all the unique atomic configurations in a 2x2x1 supercell, using the program Site-Occupation Disorder (SOD), and optimized with the General Utility Lattice Program (GULP) using Sutton-Chen interatomic potentials. Each catalyst had 101 unique bulk models that were developed into surface models, which were constructed using the two-region surface technique before the surface energies were determined. The planes and compositions with lowest surface energies were chosen as the representative models for the surface structure of the bimetallic catalysts. These representative models will now be used in a computational study of the HyS process for the production of hydrogen. Keywords: HyS process, platinum, palladium, solid-state, catalyst, Site-Occupation Disorder.

A tale of hydrogen abstraction, initially detectedviaX-ray diffraction

2014 ◽  
Vol 70 (3) ◽  
pp. 250-255 ◽  
Author(s):  
Alice K. Hui ◽  
Chun-Hsing Chen ◽  
Adam M. Terwilliger ◽  
Richard L. Lord ◽  
Kenneth G. Caulton
Keyword(s):  
Solid State ◽  
Density Functional ◽  
Computational Study ◽  
Hydrogen Abstraction ◽  
Open Shell ◽  
X Ray Diffraction ◽  
Neutral Radical ◽  
X Ray ◽  
Chloride Ligand ◽  
Synthetic Reaction

Reaction of a bis-tetrazinyl pyridine pincer ligand, btzp, with a vanadium(III) reagent gives not a simple adduct but dichlorido{3-methyl-6-[6-(6-methyl-1,2,4,5-tetrazin-3-yl-κN2)pyridin-2-yl-κN]-1,4-dihydro-1,2,4,5-tetrazin-1-yl-κN1}oxidovanadium(IV) acetonitrile 2.5-solvate, [V(C11H10N9)Cl2O]·2.5CH3CN, a species which X-ray diffraction reveals to have one H atom added to one of the two tetrazinyl rings. This H atom was first revealed by a short intermolecular N...Cl contact in the unit cell and subsequently established, from difference maps, to be associated with a hydrogen bond. One chloride ligand has also been replaced by an oxide ligand in this synthetic reaction. This formula for the complex, [V(Hbtzp)Cl2O], leaves open the question of both ligand oxidation state and spin state. A computational study of all isomeric locations of the H atom shows the similarity of their energies, which is subject to perturbation by intermolecular hydrogen bonding found in X-ray work on the solid state. These density functional calculations reveal that the isomer with the H atom located as found in the solid state contains a neutral radical Hbtzp ligand and tetravalentd1V center, but that these two unpaired electrons are more stable as an open-shell singlet and hence antiferromagnetically coupled.

Direct investigation of chalcogen bonds by multinuclear solid-state magnetic resonance and vibrational spectroscopy

2020 ◽  
Vol 22 (7) ◽  
pp. 3817-3824 ◽  
Author(s):  
Vijith Kumar ◽  
Yijue Xu ◽  
César Leroy ◽  
David L. Bryce
Keyword(s):  
Solid State ◽  
Magnetic Resonance ◽  
Vibrational Spectroscopy ◽  
Computational Study ◽  
Chalcogen Bond ◽  
Direct Investigation

We report a multifaceted experimental and computational study of three self-complementary chalcogen-bond donors as well as a series of seven chalcogen bonded cocrystals.

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