One-electron reduction of iron(II) porphyrin and characterization of iron(I) porphyrin in aqueous medium. Steady-state and pulse radiolysis studies

1984 ◽  
Vol 88 (24) ◽  
pp. 5836-5840 ◽  
Author(s):  
D. Brault ◽  
R. Santus ◽  
E. J. Land ◽  
A. J. Swallow
Keyword(s):  
Steady State ◽  
Aqueous Medium ◽  
Pulse Radiolysis ◽  
Reduction Of Iron ◽  
Electron Reduction

The one- and two-electron reduction of 2-thioriboflavin by radical anions of CO2 and dithiothreitol

1986 ◽  
Vol 64 (1) ◽  
pp. 67-70 ◽  
Author(s):  
Parminder S. Surdhar ◽  
David A. Armstrong ◽  
Vincent Massey
Keyword(s):  
Steady State ◽  
Rate Constants ◽  
Radical Anion ◽  
Pulse Radiolysis ◽  
Continuous Production ◽  
Radical Anions ◽  
Reduction Step ◽  
Equivalence Point ◽  
Electron Reduction ◽  
The One

The one- and two-electron reductions of 2-thioriboflavin with[Formula: see text] and cyclic disulphide anion of dithiothreitol [Formula: see text] have been studied by the steady state γ and pulse radiolysis techniques. The [Formula: see text] radical reacted with 2-thioriboflavin to give the neutral semiquinone (•FlH) and the radical anion (•Fl−) at pH 5 and 10 respectively. The pK of the •FlH radical was determined to be 7.4. In the case of the anion, the 2-thioriboflavin spectrum is similar in shape to that of FAD radical anion, but red shifted by 40–50 nm. Red shifts are also seen in the neutral •FlH form for the 370-nm peak and 580-nm shoulder. However, in addition, there is strong enhancement of the absorbance at 500 nm. The spectrum of 2-thioriboflavin semiquinone produced in the presence of 2–5 mM dithiothreitol was perturbed, as was observed previously for unsubstituted flavin semiquinones in the presence of sulphydryls. The rate constants for the initial one-electron reduction step viz: [Formula: see text] were 4.0 ± 0.5 × 109 M−1 s−1 and 1.3 ± 0.2 × 109 M−1 s−1 at pH 7 and 10 respectively. The corresponding rate for the reaction of [Formula: see text] with 2-thioriboflavin at pH 7 was determined to be 2.4 ± 0.2 × 109 M−1 s−l. The continuous production of [Formula: see text] radicals by γ radiolysis reduced 2-thioriboflavin to the dihydro form, and the flavin was regenerated on the addition of air. The[Formula: see text] radical also effected a two-electron reduction. However, in this case, if the process was taken beyond the equivalence point, the dihydroflavin spectrum was bleached and the oxidized flavin could not be recovered.

Steady-state Characterization of LLC-based Single-Stage AC/DC Converter Based on Numerical Analysis

2021 ◽  
pp. 1-1
Author(s):  
Xiang Li ◽  
Liuniu Guo ◽  
Tianchen Lang ◽  
Daorong Lu ◽  
Khalil Alluhaybi ◽  
...  
Keyword(s):  
Steady State ◽  
Numerical Analysis ◽  
Single Stage

Steady-State Parametric Optimization and Transient Characterization of Heat Flow Regulation With Binary Diffusion

2020 ◽  
Vol 10 (12) ◽  
pp. 1996-2007
Author(s):  
Tanya Liu ◽  
James W. Palko ◽  
Joseph S. Katz ◽  
Feng Zhou ◽  
Ercan M. Dede ◽  
...  
Keyword(s):  
Steady State ◽  
Heat Flow ◽  
Parametric Optimization ◽  
Flow Regulation ◽  
Binary Diffusion

Synthesis and Characterization of Tris(trimethyltin) Thiophosphate (Me3Sn)3PO3S

1993 ◽  
Vol 48 (12) ◽  
pp. 1781-1783 ◽  
Author(s):  
Abdel-Fattah Shihada
Keyword(s):  
Aqueous Medium ◽  
Raman Spectra ◽  
Mass Spectra ◽  
Ir And Raman Spectra ◽  
Synthesis And Characterization ◽  
Polymeric Structure ◽  
Ir And Raman

(Me3Sn)3PO3S has been prepared from the reaction of Me3SnCl with Na3PO3S • 12 H2O under cooling in aqueous medium. Its IR and Raman spectra are found to be consistent with a polymeric structure with tetra- and penta-coordinated tin atoms. The 31P NMR and mass spectra of (Me3Sn)3PO3S are reported and discussed.

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