The mechanism of sulphide oxidation by Mortierellaisabellina NRRL 1757

1982 ◽  
Vol 60 (19) ◽  
pp. 2420-2425 ◽  
Author(s):  
Herbert L. Holland ◽  
Ian M. Carter
Keyword(s):  
Oxygen Atom ◽  
Electrophilic Attack ◽  
Sulphide Oxidation ◽  
Enzymic Oxidation ◽  
Oxygen Complex ◽  
Mechanism Of Oxidation

A series of aryl substituted phenyl and benzyl methyl sulphides has been oxidized to the corresponding sulphoxides by Mortierellaisabellina NRRL 1757. The oxygen atom introduced during this enzymic oxidation is derived from the atmosphere and not from water. The rates of oxidation have been determined by uv analysis, and correlated with the Hammett p sigma constants for the phenyl methyl sulphide series. The value of ρ = −0.67 so obtained is interpreted in terms of a mechanism of oxidation at sulphur involving an electrophilic attack on the sulphide sulphur by the enzymic activated iron–oxygen complex, followed by conversion of the resulting sulphur cation to sulphoxide.

Identification of An Interstitial Carbon – Interstitial oxygen Complex in Silicon

1987 ◽  
Vol 104 ◽  
Author(s):  
J. M. Trombetta ◽  
G. D. Watkins
Keyword(s):  
Carbon Atom ◽  
Oxygen Atom ◽  
Lattice Relaxation ◽  
Luminescence Spectra ◽  
Interstitial Oxygen ◽  
Epr Spectrum ◽  
Interstitial Carbon ◽  
Oxygen Complex ◽  
Interaction Tensor ◽  
Carbon Interstitial

ABSTRACTThe Si-G15 EPR spectrum and the 0.79eV “C-line” luminescence spectra in silicon are shown to arise from an interstitial carbon - interstitial oxygen complex. The g-tensor and 13C hyperfine interaction tensor indicate the structure in the vicinity of the carbon atom while stress alignment studies reveal the configuration near the oxygen atom. The pairing of the two impurities leads to a lattice relaxation which serves to stabilize the complex against dissociation.

scholarly journals Aqueous trifluoroacetic acid as a medium for organic reactions. II. The oxidation of hydrocarbons by manganese(VII)

1978 ◽  
Vol 56 (9) ◽  
pp. 1273-1279 ◽  
Author(s):  
Ross Stewart ◽  
Udo A. Spitzer
Keyword(s):  
Isotope Effect ◽  
Trifluoroacetic Acid ◽  
Reaction Rates ◽  
Acidity Function ◽  
Hydrogen Atoms ◽  
Electrophilic Attack ◽  
Normal Alkanes ◽  
First Order ◽  
Oxidation Of Hydrocarbons ◽  
Mechanism Of Oxidation

The oxidation of 11 alkanes, 4 cycloalkanes, and 10 arenes by potassium permanganate in aqueous trifluoroacetic acid has been studied. The reaction rates are approximately first order in hR, the antilogarithm of the acidity function −HR, and the active oxidant is believed to be MnO3+, either free or complexed. The rate of abstraction of primary, secondary, and tertiary hydrogen atoms in the C5H12 isomers is in the ratio 1:60:2100 and the rate per methylene in normal alkanes increases with increasing chain length. Cyclohexane is the least reactive of the cycloalkanes and the isotope effect in the oxidation of cyclo-C6D12 is 4.3 at 25 °C. The mechanism of oxidation of the aliphatic hydrocarbons is believed to be hydrogen-atom abstraction by MnO3+. The oxidation of arenes C6H5Z has a ρ+ value of −5.29 when appropriate σ+ values of Z are used, and there is no isotope effect when the reaction rates of C6H5CH3, C6H5CD3, and C6D5CD3 are compared. The mechanism of oxidation of the aromatic compounds is believed to be electrophilic attack of MnO3+ at the activated positions of the ring followed by rapid degradation of the ring system.

A study of twinning in YBa2Cu3O7−x by large-angle convergent-beam electron diffraction

1990 ◽  
Vol 48 (4) ◽  
pp. 20-21
Author(s):  
P.A. Midgley ◽  
R. Vincent ◽  
D. Cherns
Keyword(s):  
Electron Diffraction ◽  
Oxygen Atom ◽  
Strain Field ◽  
Large Angle ◽  
Convergent Beam Electron Diffraction ◽  
Orthorhombic Distortion ◽  
Beam Electron ◽  
Resultant Powder ◽  
Convergent Beam ◽  
Mesh Grid

The oxygenation of YBa2Cu3O7−x (YBCO) leads to an orthorhombic distortion of the unit cell to accommodate the extra oxygen atom. This makes the formation of twins energetically favourable with CuO4 planar unit chains running alternately along the a and b axes of the parent tetragonal structure. The geometry of this twinning is such that four possible twin variants may co-exist with the twin boundaries lying in the (110) or (110) planes of the deformed structure. The traces of these planes are not mutually perpendicular and thus the crystal is strained to allow for the mismatch. It is to the nature of this strain field that this work has been addressed.Sintered samples were prepared by crushing and dispersing the resultant powder onto a very fine Cu mesh grid. Single crystals were chemically thinned to perforation. No discernible artefacts were seen and similar results were obtained with either method.

Trivacancy-oxygen complex in silicon: Local vibrational mode characterization

2009 ◽  
Vol 404 (23-24) ◽  
pp. 4568-4571
Author(s):  
L.I. Murin ◽  
B.G. Svensson ◽  
J.L. Lindström ◽  
V.P. Markevich ◽  
C.A. Londos
Keyword(s):  
Vibrational Mode ◽  
Local Vibrational Mode ◽  
Oxygen Complex

Mechanism of Oxidation Reactions of Bromine

1958 ◽  
Vol 14 (5_6) ◽  
pp. 357-360
Author(s):  
K. C. Grover ◽  
R. C. Mehrotra
Keyword(s):  
Oxidation Reactions ◽  
Mechanism Of Oxidation

Mechanism of Oxidation Reactions of Bromine

1958 ◽  
Vol 14 (5_6) ◽  
pp. 345-356 ◽  
Author(s):  
K. C. Grover ◽  
R. C. Mehrotra
Keyword(s):  
Oxidation Reactions ◽  
Mechanism Of Oxidation

Kinetics and Mechanism of Oxidation of Labetalol by Hexacyanoferrate(III) in Alkaline Medium

2012 ◽  
Vol 3 (2) ◽  
pp. 131-133
Author(s):  
ANNAPURNA NOWDURI ◽  
◽  
Apparao Babu Duggada ◽  
Vijaya Raju Kurimella
Keyword(s):  
Alkaline Medium ◽  
Kinetics And Mechanism ◽  
Mechanism Of Oxidation

Fast oxygen atom facility for studies related to low earth orbit activities

1992 ◽  
Author(s):  
G. CALEDONIA ◽  
R. KRECH ◽  
B. UPSCHULTE ◽  
D. SONNENFROH ◽  
D. OAKES ◽  
...  
Keyword(s):  
Oxygen Atom ◽  
Low Earth Orbit ◽  
Earth Orbit
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