Solid-state and Computational Study of “Venus fly-trap” Geometric Parameters for 1,5-Cyclooctadiene in PdIIand PtIIβ-Enaminonato Complexes

2018 ◽  
Vol 644 (14) ◽  
pp. 763-774 ◽  
Author(s):  
Tania N. Hill ◽  
Andreas Roodt
Keyword(s):  
Solid State ◽  
Computational Study ◽  
Geometric Parameters

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.

A Computational Study of the Thermal Performance of a 69 kV Solid State Current Limiter Submerged in FR3 Dielectric Coolant

2008 ◽  
Author(s):  
Ronald Warzoha ◽  
Patrick Kirby ◽  
Amy Fleischer ◽  
Mahesh Gandhi ◽  
Ashok Sundaram
Keyword(s):  
Solid State ◽  
Thermal Management ◽  
Distribution Systems ◽  
Waste Heat ◽  
Computational Study ◽  
Small Scale ◽  
Phase System ◽  
Fault Current ◽  
Fault Current Limiter ◽  
Current Limiter

This paper presents the results of thermal modeling of a unique 69 kV 3000A Solid State Fault Current Limiter (SSFCL) developed by Silicon Power of Malvern, PA with support of EPRI. The development of the Solid State Fault Current Limiter is expected to modernize power distribution systems through the use of small-scale solid-state power devices. The use of this new design is expected to increase reliability and functionality while reducing footprint. However, as the footprint is reduced, the heat flux for the system is increased, leading to the significant possibility of device failure due to thermal excursions if the heat load is not properly managed. The high heat loading requires the use of aggressive thermal management in the form of liquid cooling of the electronics. This system features 288 kW of waste heat in the three phase system. The system is submerged in FR3 dielectric coolant and the desired thermal management system is liquid natural convection within the tank and shed to the ambient through an external finned array system. This project explores the feasibility of this system design.

Ru(II) complexes containing (2-(pyren-1-ylmethylene)hydrazinyl)benzothiazole: Synthesis, solid-state structure, computational study and catalysis in N-alkylation reactions

2020 ◽  
Vol 512 ◽  
pp. 119864
Author(s):  
Kaliyappan Murugan ◽  
Subbarayan Vijayapritha ◽  
Periasamy Viswanathamurthi ◽  
Kandasamy Saravanan ◽  
Paranthaman Vijayan ◽  
...  
Keyword(s):  
Solid State ◽  
Computational Study ◽  
State Structure ◽  
Solid State Structure ◽  
Alkylation Reactions
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