Photogenerated arylnitrenium ions: absorption spectra and absolute rate constants for tert-butyl(4-halo-2-acetylphenyl)nitrenium ions measured by time-resolved laser spectroscopy

1993 ◽  
Vol 115 (21) ◽  
pp. 9870-9871 ◽  
Author(s):  
Gary B. Anderson ◽  
Daniel E. Falvey
Keyword(s):  
Absorption Spectra ◽  
Laser Spectroscopy ◽  
Rate Constants ◽  
Absolute Rate ◽  
Time Resolved ◽  
Nitrenium Ions ◽  
Tert Butyl ◽  
Arylnitrenium Ions

Structures of Reactive Nitrenium Ions:  Time-Resolved Infrared Laser Flash Photolysis and Computational Studies of SubstitutedN-Methyl-N-arylnitrenium Ions

2000 ◽  
Vol 122 (34) ◽  
pp. 8271-8278 ◽  
Author(s):  
Sanjay Srivastava ◽  
Patrick H. Ruane ◽  
John P. Toscano ◽  
Michael B. Sullivan ◽  
Christopher J. Cramer ◽  
...  
Keyword(s):  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Infrared Laser ◽  
Computational Studies ◽  
Time Resolved ◽  
Nitrenium Ions ◽  
Arylnitrenium Ions

scholarly journals Measurements of Rate Constants for HO2 + NO and NH2 + NO Reactions by Time-Resolved Photoionization Mass Spectrometry

1995 ◽  
Vol 16 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Takashi Imamura ◽  
Nobuaki Washida
Keyword(s):  
Mass Spectrometry ◽  
Rate Constants ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Absolute Rate ◽  
Time Resolved ◽  
Photoionization Mass Spectrometry

Absolute rate constants for HO2 + NO and NH2 + NO reactions were measured by a photoionization mass spectrometry coupled with a laser flash photolysis. HO2 and NH2 radicals were photoionized by an Ar resonance lamp and were detected as their parent ions (HO2+ and NH2+). The rate constants were determined to be K(HO2 + NO)=(6.5  ± 2.0) 10−12cm3molecule−1s−1K(NH2 + NO)=(1.9  ± 0.3) 10−11cm3molecule−1s−1 Both rates are consistent with those previously reported.

Triplet-State Kinetics of 2,5 Diphenyloxazole (PPO)

1988 ◽  
Vol 42 (1) ◽  
pp. 27-31
Author(s):  
A. N. Dharamsi ◽  
Shawpin Jong
Keyword(s):  
Excited State ◽  
Triplet State ◽  
Absorption Spectra ◽  
Rate Constants ◽  
Intersystem Crossing ◽  
Time Resolved ◽  
Probe Technique ◽  
Pump And Probe ◽  
Kinetics Of ◽  
Triplet Absorption

Time-resolved excited-state triplet-triplet absorption spectra were measured for solutions of 2,5 diphenyloxazole (PPO) in various solvents, with the use of a pump and probe technique. The rate constants for intersystem crossing, triplet deactivation by oxygen, and triplet-triplet self-quenching are obtained. The latter two rate constants are substantially larger than the corresponding rate constants for 2-(1 naphthyl)-5-phenyloxazole-αNPO.

IDENTIFICATION OF RATE CONSTANTS AND NONOBSERVABLE ABSORPTION SPECTRA IN NONLINEAR BIOCHEMICAL REACTION DYNAMICS

2004 ◽  
Vol 14 (06) ◽  
pp. 2081-2092 ◽  
Author(s):  
D. MARAUN ◽  
W. HORBELT ◽  
H. RUST ◽  
J. TIMMER ◽  
H. P. HAPPERSBERGER ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Rate Constants ◽  
Reaction Dynamics ◽  
Biochemical Reaction ◽  
Multiple Shooting ◽  
Specific Rate ◽  
Time Resolved ◽  
Time Courses ◽  
Kinetics Of ◽  
Shooting Algorithm

On analyzing data of biochemical reaction dynamics monitored by time-resolved spectroscopy, one faces the problem that the concentration time courses of the involved components are not directly observed, but the superposition of their absorption spectra. Furthermore the single spectra are often unknown, because the corresponding reagents cannot be isolated. We propose a method based on Bock's multiple shooting algorithm to estimate the rate constants and individual spectra simultaneously. Applying this procedure to a biochemical reaction we identify the specific rate constants characterizing the reaction dynamics as well as the nonobservable absorption spectra. The results lead to a better understanding of the kinetics of a novel modification reaction which was used as trapping reaction in disulfide bond mediated protein folding reactions.

The pulse radiolysis of aqueous solutions of some inorganic compounds

1965 ◽  
Vol 286 (1406) ◽  
pp. 320-336 ◽  
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Absorption Spectra ◽  
Rate Constants ◽  
Pulse Radiolysis ◽  
Inorganic Compounds ◽  
Absolute Rate ◽  
Transient Species ◽  
Temperature Coefficients ◽  
Complex Metal

The reactions of the hydrated electron, e — aq. with a variety of inorganic metal ions, complex metal ions and anions have been investigated with pulses of 4 MeV electrons. Absolute rate constants have been measured in each case and some temperature coefficients have also been determined. Absorption spectra of transient species produced by the pulse have been obtained. Some of these species are unstable valency states produced by reduction withe — aq. , e.g. Ni + , Cr v ; others are the result of oxidation by OH, e.g. Cu 3+ . We have obtained rate constants for the reactions OH+Cu 2+ and H+MnO - 4 . The significance of the rate constants and spectra is discussed.

Absolute rate constants for hydrocarbon autoxidation. 24. Rate constants and Arrhenius parameters for reaction of tert-butylperoxy radicals with 3-methylpentane

1978 ◽  
Vol 56 (2) ◽  
pp. 170-175 ◽  
Author(s):  
J. A. Howard ◽  
J. H. B. Chenier ◽  
D. A. Holden
Keyword(s):  
Rate Constants ◽  
Arrhenius Equation ◽  
Absolute Rate ◽  
Reaction Products ◽  
Butyl Hydroperoxide ◽  
Tert Butyl ◽  
A Value ◽  
Tert Butyl Hydroperoxide ◽  
Reduction With Triphenylphosphine ◽  
Major Reaction

Autoxidation of 3-methylpentane in the presence of tert-butyl hydroperoxide gives, after reduction with triphenylphosphine, 3-methyl-3-pentanol and 3-methyl-2-pentanol as the major reaction products. The overall rate constant for reaction of (CH3)3COO· with this substrate at 30 °C is 0.008 ± 0.001 M−1 s−1 which consists of k/tertiary C—H = 0.007 ± 0.001 M−1 s−1 and k/secondary C—H = 0.0002 ± 0.0001 M−1 s−1. The products from cooxidation of cumene and 3-methylpentane in the presence of tert-butyl hydroperoxide are formed in yields which are consistent with these rate constants relative to a value of 0.16 M−1 s−1 for cumene. The Arrhenius equations for reaction of (CH3)3COO• with the t-C—H and s-C—H of 3-methylpentane relative to the Arrhenius equation for reaction of (CH3)3COO• with cumene (log (k10/M−1 s−1) = (8.7 ± 0.3) − (13.2 ± 0.4)/θ) are[Formula: see text]respectively, where θ = 2.303 RT kcal mol−1.

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