Sulfur Transfer Versus Phenyl Ring Transfer in the Gas Phase: Sequential Loss of CH3OH and CH3O–P=O from Protonated Phosphorothioates

2018 ◽  
Vol 30 (3) ◽  
pp. 459-467
Author(s):  
Xiaoping Zhang ◽  
Honghan Chen ◽  
Yin Ji ◽  
Kezhi Jiang ◽  
Huanwen Chen
Keyword(s):  
Gas Phase ◽  
Phenyl Ring ◽  
Sulfur Transfer ◽  
Sequential Loss

Synthetic applications of intramolecular insertion in arylcarbenes. VII. Aryl-substituted benzocycloalkenylidenes

1984 ◽  
Vol 37 (9) ◽  
pp. 1915 ◽  
Author(s):  
WD Crow ◽  
U Engkaninan-Low ◽  
YT Pang
Keyword(s):  
Gas Phase ◽  
Phenyl Ring ◽  
Side Chain ◽  
Electronic Effects ◽  
Carbene Insertion

A series of benzo-fused cyclic carbenes, bearing suitably located alkoxy substituents in the phenyl ring, has been generated in the gas phase and pyrolysed at 250�/0.002-0.40 mm. In all cases, carbene insertion into the adjacent C-H bond (Bamford-Stevens insertion) occurs, either exclusively or predominantly, with up to 35% 1,5 C-H insertion in the alkoxy side chain to form peri-fused tricyclic heterocycles. These results are rationalized in terms of geometrical and electronic effects.

Quantum chemical prediction of structure and stability of the benzodihydropyrimidine tautomers

2014 ◽  
Vol 13 (07) ◽  
pp. 1450056 ◽  
Author(s):  
Robert Dobosz ◽  
Ryszard Gawinecki
Keyword(s):  
Gas Phase ◽  
Quantum Chemical ◽  
Phenyl Ring ◽  
Optimization Procedure ◽  
Pyrimidine Ring ◽  
Phase 2 ◽  
Structure And Stability ◽  
Stability Data

B3LYP/maug-cc-pVTZ and MP2/maug-cc-pVTZ calculations show that 3,4-dihydro-quinazoline and its 2- and/or 4-methyl and -phenyl substituted derivatives in solution (chloroform, DMSO, methanol) are only by 0.3 kcal/mol–2.2 kcal/mol more stable than the respective tautomeric 1,4-dihydroquinazolines (the available literature experimental stability data are not coherent). In the gas phase, 2- and/or 4-substituted tautomers of 3,4-dihydroquinazoline are also energetically preferred (B3LYP/maug-cc-pVTZ, MP2/maug-cc-pVTZ and CCSD/cc-pVDZ calculations lead to the same conclusion). In vacuum, 1,4-dihydro tautomer is by 0.1 kcal/mol–0.2 kcal/mol more stable only for unsubstituted dihydro-quinazoline. The observed tautomeric preference was found almost independent on substitution and solvent used. The optimization procedure used shows that the pyrimidine ring in dihydropyrimidines studied is not planar. Noncoplanarity of the 2-phenyl ring and C = N bond in the respective compounds studied is responsible for the weakened conjugation of these two moieties.

scholarly journals Influence of catecholic ring torsion on hydroxyflavones

2020 ◽  
Vol 13 (1) ◽  
pp. 49-55
Author(s):  
Martin Michalík ◽  
Monika Biela ◽  
Denisa Cagardová ◽  
Vladimír Lukeš
Keyword(s):  
Gas Phase ◽  
Phenyl Ring ◽  
Density Functional ◽  
Hydroxyl Group ◽  
Torsional Deformation ◽  
Functional Theory ◽  
Electron Transitions ◽  
The Density Functional Theory ◽  
Intramolecular Hydrogen ◽  
Theoretical Results

AbstractSystematic quantum chemical investigation of quercetin and selected eight mono- and bihydroxyflavonols is presented. Structural analysis based on the Density Functional Theory showed that the energetically preferred conformation of flavonols substituted at the C5 and C3 atoms by a hydroxyl group is stabilised via intramolecular hydrogen bonds occurring between the (C4)O···HO(3 or 5) atomic pairs. Depending on the hydroxyl group positions, energetically preferred torsional orientation of the phenyl ring with respect to the planar benzo-γ-pyrone moiety changed from 0 to 180 degrees. Gas-phase electron transitions were investigated using the time-dependent DFT treatment. The dependence of maximal wavelengths on the torsional deformation of the phenyl ring is of a similar shape, i.e. minima observed for the perpendicular orientation and maxima for the planar one. Shape and energies of the Highest Occupied (HOMO) and Lowest Unoccupied (LUMO) Molecular Orbitals were compared. The obtained theoretical results were compared with available experimental data.

Gas-phase elimination kinetics of .omega.-phenylalkyl chlorides. Participation of the phenyl ring

1985 ◽  
Vol 89 (3) ◽  
pp. 551-552 ◽  
Author(s):  
Gabriel Chuchani ◽  
Alexandra Rotinov ◽  
Ignacio Martin
Keyword(s):  
Gas Phase ◽  
Phenyl Ring ◽  
Elimination Kinetics ◽  
Kinetics Of ◽  
Phase Elimination

scholarly journals Sulfur Transfer via Gas Phase in Iron-making Blast Furnace under Intensive Coal Injection

2007 ◽  
Vol 33 (4) ◽  
pp. 165-168
Author(s):  
MATSUI Yoshiyuki ◽  
TADAI Rikizou ◽  
ITO Kenji ◽  
MATSUO Tadasu ◽  
KADOGUCHI Korehito ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Gas Phase ◽  
Sulfur Transfer ◽  
Coal Injection

scholarly journals Photoelektronen-Spektren und Moleküleigenschaften, LXIII Ionisierungsenergien von Phenyl-Methyl-Tellurid und Vergleich der Effekte von Sauerstoff-, Schwefel-, Selen- und Tellur-Substituenten auf das Benzol-π-System / Photoelectron Spectra and Molecular Properties, LXIII Ionization Energies of Phenyl Methyl Telluride and Comparison of Effects of Oxygen, Sulphur, Selenium and Tellurium Substituents on the Benzene π System

1976 ◽  
Vol 31 (12) ◽  
pp. 1611-1615 ◽  
Author(s):  
Galina Tschmutowa ◽  
Hans Bock
Keyword(s):  
Gas Phase ◽  
Dihedral Angle ◽  
Energy Region ◽  
Phenyl Ring ◽  
Photoelectron Spectrum ◽  
Lone Pair ◽  
Low Energy ◽  
Molecular Properties ◽  
Photoelectron Spectra ◽  
Overlapping Bands

The photoelectron spectrum of H5C6-Te-CH3 displays in its low energy region overlapping bands of gas-phase conformers. Depending on the dihedral angle between the plane of the phenyl ring and the tellurium lone pair, the π conjugation amounts to only 0.1 eV and 0.3 eV, respectively. These values are compared to the considerably larger ones found for the analogous phenyl derivatives H5C6-X-CH3 with X = O, S and Se.

Reactions of Bare Silicon Cluster Ions: Prototypical Deposition and Etching Versus Cluster Size

1986 ◽  
Vol 75 ◽  
Author(s):  
M. L. Mandich ◽  
W. D. Reents ◽  
V. E. Bondybey
Keyword(s):  
Gas Phase ◽  
Room Temperature ◽  
Lone Pair ◽  
Cluster Ions ◽  
Laser Evaporation ◽  
Silicon Cluster ◽  
Bulk Silicon ◽  
Gas Phase Reactions ◽  
Silicon Clusters ◽  
Sequential Loss

AbstractPrototypical silicon deposition and etching reactions have been observed in gas phase reactions of size selected bare silicon cluster ions at room temperature. Laser evaporation of bulk silicon just outside the ion cell of a Fourier transform mass spectrometer produces abundant positive and negative silicon cluster ions. These cluster ions are trapped inside the cell for subsequent study of their bimolecular reactivity with various neutral reagents. Deposition type reactions occur with silanes, e.g. CH3SiH3, and increase the number of silicon atoms in the cluster. Etching reactions occur in reactions with certain halogen or oxygen containing reagents. For example, NO2 and XeF2 react to destroy the silicon clusters by sequential loss of a silicon atom. Overall the reactivity of small silicon cluster ions correlates with chemistry which occurs at two distinct types of dangling bonds in the clusters: either a lone pair of electrons or a single unpaired electron.

Residual Gas Reactions in the Electron Microscope: I. Qualitative Observations on the Water Gas Reaction

1968 ◽  
Vol 26 ◽  
pp. 292-293
Author(s):  
Richard E. Hartman ◽  
Roberta S. Hartman ◽  
Peter L. Ramos
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Gas Phase ◽  
Absolute Temperature ◽  
Residual Gas ◽  
Gas Reactions ◽  
Image Position ◽  
The Right ◽  
Water Gas ◽  
Thinning Rate

The action of water and the electron beam on organic specimens in the electron microscope results in the removal of oxidizable material (primarily hydrogen and carbon) by reactions similar to the water gas reaction .which has the form:The energy required to force the reaction to the right is supplied by the interaction of the electron beam with the specimen.The mass of water striking the specimen is given by:where u = gH2O/cm2 sec, PH2O = partial pressure of water in Torr, & T = absolute temperature of the gas phase. If it is assumed that mass is removed from the specimen by a reaction approximated by (1) and that the specimen is uniformly thinned by the reaction, then the thinning rate in A/ min iswhere x = thickness of the specimen in A, t = time in minutes, & E = efficiency (the fraction of the water striking the specimen which reacts with it).

Integration of Core-Edge Spectroscopy Methods for the Study of Polymers

1996 ◽  
Vol 54 ◽  
pp. 154-155
Author(s):  
E. G. Rightor
Keyword(s):  
Excited State ◽  
Polymer Blends ◽  
Gas Phase ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Electronic States ◽  
Core Electron ◽  
Bulk Solids ◽  
Development Application

Core edge spectroscopy methods are versatile tools for investigating a wide variety of materials. They can be used to probe the electronic states of materials in bulk solids, on surfaces, or in the gas phase. This family of methods involves promoting an inner shell (core) electron to an excited state and recording either the primary excitation or secondary decay of the excited state. The techniques are complimentary and have different strengths and limitations for studying challenging aspects of materials. The need to identify components in polymers or polymer blends at high spatial resolution has driven development, application, and integration of results from several of these methods.

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