Study of the Reactions of Platinum Macrocyclic Complex Ions with Free Radicals Formed by Pulse Radiolysis of Aqueous Media

1996 ◽  
Vol 35 (1) ◽  
pp. 124-130 ◽  
Author(s):  
W. L. Waltz ◽  
J. Lilie ◽  
S. Chandrasekhar ◽  
D. Woo ◽  
K. Brown
Keyword(s):  
Free Radicals ◽  
Pulse Radiolysis ◽  
Aqueous Media ◽  
Macrocyclic Complex ◽  
Complex Ions

Formation and characterization of transitory platinum–ammonia complex ions using pulse radiolysis

1981 ◽  
Vol 59 (24) ◽  
pp. 3319-3325 ◽  
Author(s):  
Hasan M. Khan ◽  
William L. Waltz ◽  
Robert J. Woods ◽  
Jochen Lilie
Keyword(s):  
Hydrogen Atom ◽  
Pulse Radiolysis ◽  
Aqueous Media ◽  
Hydrated Electron ◽  
Complex Ions ◽  
Initial Product ◽  
Detection Analysis ◽  
Diffusion Controlled ◽  
Ammonia Complex ◽  
Long Term Behavior

The reactions of tetraammineplatinum(II) complex ion with the hydrated electron and hydrogen atom have been investigated in aqueous media using the technique of pulse radiolysis coupled with absorption and conductivity detection. Analysis has also been carried on pulse-irradiated solutions for the formation of free ammonia and for changes in concentration of Pt(II). The hydrated electron and hydrogen atom react with the complex at near diffusion-controlled rates, with the respective rate constant being 1.9 ± 0.1 × 1010 M−1 s−1 and 2.8 ± 0.3 × 1010 M−1 s−1. The nascent products of these reactions are shown to be different transitory species. For the electron reaction, the initial product is Pt(NH3)4+ in which the metal center is formally Pt(I). In acidic media, there is a subsequent and rapid release of two ammonia ligands, with only the second step being measurable (k = 4.2 ± 1.7 × 104 s−1). In the reaction of H atom, the results support the occurrence of an addition process, giving rise to a hydrido type product. This species undergoes a first-order reaction (k = 2.2 ± 0.6 × 104 s−1); however the process is not associated with a change in conductivity, and thus it is not one involving loss of ammonia. Subsequent to this process, the loss of one ammonia ligand is observed, with k = 2.0 ± 0.6 × 103 s−1. The natures of these transients and the long term behavior of these systems are discussed.

scholarly journals Thiyl and phenoxyl free radicals and NADH Direct observation of one-electron oxidation

1986 ◽  
Vol 240 (3) ◽  
pp. 897-903 ◽  
Author(s):  
L G Forni ◽  
R L Willson
Keyword(s):  
Electron Transfer ◽  
Free Radicals ◽  
Hydrogen Atom ◽  
Pulse Radiolysis ◽  
Biological Significance ◽  
Transfer Reactions ◽  
Absolute Rate ◽  
Transfer Processes ◽  
Biochemical Systems ◽  
Electron Transfer Processes

Absolute rate constants for the reaction of NADH with thiyl free radicals derived from various sulphur-containing compounds of biological significance were measured by using the technique of pulse radiolysis. These and related reactions with phenoxyl free radicals are believed to occur through one-electron-transfer processes. Further evidence comes from studies with deuterated NADH. The results support the possibility that, in biochemical systems, thiols may act as catalysts linking hydrogen-atom and electron-transfer reactions.

Pulse radiolysis studies of U(VI) complexes in aqueous media

1981 ◽  
Vol 43 (5) ◽  
pp. 897-899 ◽  
Author(s):  
K. Nash ◽  
W. Mulac ◽  
M. Noon ◽  
S. Fried ◽  
J.C. Sullivan
Keyword(s):  
Pulse Radiolysis ◽  
Aqueous Media
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