Redox reactions in aqueous solutions of PtBr2-4 and PtBr2-6

Standard redox potentials, E0s, and redox processes of U, Np and Pu ions in acidic aqueous solutions are reviewed and evaluated critically. The E0sof reversible redox processes, MO22+/MO2+ and M4+/M3+ (M: U, Np or Pu) adopted are those proposed mainly by Riglet et al. on the basis of the precise correction of formal potentials, E0's, according to the improved theoretical approach to estimate the activity coefficient. Electrode processes of the U, Np and Pu ions are discussed in terms of current-potential curves, measured so far by polarography, voltammetry or flow coulometry. Special attention is payed to the irreversible MO2+/M4+ reactions. Disproportionation reactions of MO2+ are also discussed. New substances are introduced as intermediates during reductions of MO2+ to M4+ or disproportionations of MO2+.CONTENTSIntroductionStandard redox potentials for uranium, neptunium and plutonium ions in acidic aqueous solutions2.1 Evaluation of E0 from E0' determined by electrochemical measurements2.2 Temperature dependence of E0Redox reactions of uranium, neptunium and plutonium in acidic aqueous solutions investigated by polarography or voltammetry3.1 Uranium3.2 Neptunium3.3 Plutonium3.4 Disproportionation of NpO2+, PuO2+, Np4+ and Pu4+3.5 Reduction of MO2+ and reduction intermediatesRedox reactions of uranium, neptunium and plutonium in acidic aqueous solutions investigated by flow coulometry4.1 Electrode processes of the uranium, neptunium and plutonium ions investigated by flow coulometry at the column electrode at the column electrode4.2 Disproportionation of MO2+ during the electrolysis by flow coulometry4.3 Reduction mechanisms of MO2+ (M = Np or Pu) and reduction intermediates investigated by flow coulometryConclusionsList of abbreviationsAppendixReferences

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Morphology and radical reactions of Cu(II) and Co(II) sulfonated phthalocyanines covalently linked to poly(ethyleneamide)

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424610001751 ◽

2010 ◽

Vol 14 (01) ◽

pp. 69-80 ◽

Cited By ~ 5

Author(s):

Gustavo T. Ruiz ◽

Alexander G. Lappin ◽

Guillermo Ferraudi

Keyword(s):

Aqueous Solutions ◽

Redox Reactions ◽

Radical Reactions ◽

Stable Bundles ◽

Carbon Bonds ◽

Amine Groups ◽

Covalently Linked ◽

The Stability ◽

Sulfonated Phthalocyanines

The tetrasulfonated Cu II( tspc )4-, tspc = 4,4′,4″,4‴-phthalocyaninetetrasulfonate, and the trisulfonated Co II( trspc )3-, trspc = n , n ′, n ″-phthalocyanine-trisulfonate and n, n′ and n″ indicate the sulfonated positions of the various isomers, were covalently linked to a polyethyleneimine, M n ~ 10000 and M w ~ 25000, backbone. A fraction of the amine groups in a strand was converted to Cu II pc (- SO 3)3(- SO 2 N <)\3- or Co II pc (- SO 3)2(- SO 2 N <)\2- pendants and the remaining were acetylated. Strands of the polymers, poly(K3CuIItspc) and poly(K2CoIItrspc) , formed spherical bundles with diameters ~1000 nm for poly(K3CuIItspc) and ~100 nm for poly(K2CoIItrspc) . The stability of the bundles is metal-dependent. Poly(K2CoIItrspc) forms the most stable bundles with respect to hydrolytic and redox reactions. ESR and optical spectroscopies as well as reactions of the pendants with pulse radiolytically generated radicals, namely e - sol , C•H2OH, (CH3)2COHC•H2 , CO 2•-, N 3• and SO 4•-, revealed a distribution of pendants between isolated and aggregated forms in a bundle. The reduction of the Cu(II) to Cu(I) in aqueous solutions of the poly(K3CuIItspc) was associated with pendants present in a mostly hydrophobic environment. Unstable phthalocyanine pendants with CoIII -carbon bonds are formed when CoIIpc(-SO3)2(-SO2N<)\2- reacted with C -centered radicals, ( CH3)2COHC•H2 and C•H2OH . The species with CoIII -carbon bonds were precursors to the formation of CoIpc(-SO3)2(-SO2N<)\3- pendants. The redox reactions of the pendants in these polymers are compared with those of K4CuIItspc and K3CoIItrspc .

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