Formation and characterization of platinum(III)-ammonia complex ions using pulse radiolysis

Journal Article · Wed Mar 31 23:00:00 EST 1982 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00134a045· OSTI ID:5225295

Khan, H M ^[1]; Waltz, W L; Lilie, J; Woods, R J

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1. Univ. of Saskatchewan, Saskatoon, Canada

The reactions of hydroxyl radical with tetraammineplatinum(II) perchlorate and of the hydrated electron with trans-dihydroxotetraammineplatinum(IV) perchlorate have been investigated in aqueous media with the fast-reaction technique of pulse radiolysis in conjunction with conductivity and UV-visible absorption detection. The kinetic studies have been supplemented by final-product analysis on pulse-irradiated solutions for the formation of free ammonia and for changes in the concentration of platinum(II). The hydroxyl radical reaction proceeds by an addition proces to the platinum(II) center, with a rate constant of (6.6 +/- 0.4) x 10/sup 9/ M/sup -1/ s/sup -1/. The hydrated electron reduces the platinum(IV) complex with a rate constant of (4.9 +/- 0.3) x 10/sup 10/ M/sup -1/ s/sup -1/. The nascent products of these reactions are transitory species in which the metal has a formal oxidation state of III, and evidence is presented to support their formulation as Pt(NH/sub 3/)/sub 4/(H/sub 2/O)(OH)/sup 2 +/ and Pt(NH/sub 3/)/sub 4/(OH)/sub 2//sup +/, respectively. Both species exhibit intense absorption bands with peaks near 270 nm, and they undergo reactions to yield three further transients, one of these being Pt(NH/sub 3/)/sub 4/(H/sub 2/O)/sub 2//sup 3 +/ absorbing in the region of 250 nm. The two additional transients, arising at a secondary level, exhibit absorption bands of lesser intensity with peaks in the region of 340 and 530 nm. The nature of these species and their long-term reactions are discussed. A mechanism is proposed whereby the foregoing intermediates are interrelated by acid-base, ammonia substitution, and water elimination processes.

• OSTI ID: 5225295
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 21:4; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
AMMONIA
CHEMICAL PREPARATION
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISTRY
COMPLEXES
CONCENTRATION RATIO
DECOMPOSITION
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
HYDRATION
HYDRIDES
HYDROGEN COMPOUNDS
HYDROXYL RADICALS
IRRADIATION
KINETICS
LEPTONS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
PH VALUE
PLATINUM COMPLEXES
PULSED IRRADIATION
RADIATION CHEMISTRY
RADIATION EFFECTS
RADICALS
RADIOLYSIS
REACTION KINETICS
SOLVATED ELECTRONS
SOLVATION
SPECTRA
SYNTHESIS
TRANSITION ELEMENT COMPLEXES