Electron-transfer reactions of technetium and rhenium complexes. 3. Pulse radiolysis studies on trans-(M sup III X sub 2 (DMPE) sub 2 ) sup + and (M sup I (DMPE) sub 3 ) sup + complexes in aqueous and aqueous surfactant media, where M = Tc or Re, X = Cl or Br, and DMPE = 1,2-Bis(dimethylphosphino)ethane

Journal Article · Tue Nov 26 23:00:00 EST 1991 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00024a016· OSTI ID:7273727

Roodt, A; Deutsch, E ^[1]; Sullivan, J C; Meisel, D ^[2]

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1. Univ. of Cincinnati, OH (United States)
2. Argonne National Lab., IL (United States)

Pulse radiolytic techniques have been employed to study the rate of reactions of the strong reductant e{sub aq}{sup {minus}} and the strong oxidant Cl{sub 2}{sup {minus}} with lipophilic, cationic Tc and Re complexes in aqueous and aqueous surfactant media. In aqueous media the reaction of the M(III) complexes trans-(Re{sup III}Cl{sub 2}(DMPE){sub 2}){sup +}, trans-(Re{sup III}Br{sub 2}(DMPE){sub 2}){sup +}, and trans-(Tc{sup III}Cl{sub 2}(DMPE){sub 2}){sup +} have been studied with both reagents, while the reaction of the M(I) complexes (Re{sup I}(DMPE){sub 3}){sup +} and (Tc{sup I}(DMPE){sub 3}){sup +} have been studied with Cl{sub 2}{sup {minus}}. Oxidation of the M(I) complexes cleanly yields the corresponding (M{sup II}(DMPE){sub 3}){sup +} species by an outer-sphere mechanism, whereas oxidation of the M(III) complexes appear to proceed by more complicated pathways, which could involve outer-sphere electron transfer as well as oxidative addition. All reactions proceed at or near the diffusion-controlled limit. The positively charged surfactant CTAB (Hexadecyltrimethylammonium bromide) and the uncharged surfactant Triton X-100 ({alpha}-(p-(1,1,3,3-tetra-methylbutyl)phenyl)-{omega}-hydroxypolyoxyethylene(9.5)) have little or no effect on the rates of any of the reactions studied. However, micelles formed from the negatively charged surfactant SDS (sodium dodecyl sulfate) exert a dramatic effect on reaction rates by effectively sequestering the cationic complexes and rendering them relatively unavailable for reaction with the anionic reagents e{sub aq}{sup {minus}} and Cl{sub 2}{sup {minus}}. While the anionic reagents can penetrate the SDS micelles, the cationic complexes do not appear to be released from the micelle during the lifetime of the anionic radicals (ca. 10{sup 2} {mu}s). These results have implications for the use of surfactants in electrochemical studies, as well as for the pharmacokinetics of cationic complexes of interest to nuclear medicine.

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 7273727
• Journal Information: Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 30:24; ISSN 0020-1669; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
550601 -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ABSORPTION SPECTRA
ACCELERATORS
ANIONS
ANTIMITOTIC DRUGS
AQUEOUS SOLUTIONS
BEAMS
BIOLOGICAL EFFECTS
CATIONS
CHARGED PARTICLES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISTRY
COMPLEXES
DECOMPOSITION
DIFFUSION
DISPERSIONS
DRUGS
ELECTROCHEMISTRY
ELECTRON BEAMS
ELECTRON TRANSFER
ENERGY RANGE
IONS
KINETICS
LEPTON BEAMS
LINEAR ACCELERATORS
MEV RANGE
MEV RANGE 10-100
MICELLAR SYSTEMS
MIXTURES
OXIDATION
PARTICLE BEAMS
PH VALUE
PHOSPHINES
PHOSPHORUS COMPOUNDS
RADIATION EFFECTS
RADIOLYSIS
RADIOSENSITIZERS
REACTION KINETICS
REDUCTION
RHENIUM COMPLEXES
SOLUTIONS
SPECTRA
SURFACTANTS
TECHNETIUM COMPLEXES
TRANSITION ELEMENT COMPLEXES