Trivalent nickel catalysis of the autoxidation of nickel(II) tetraglycine

Bossu, Frank P.; Paniago, Eucler B.; Margerum, Dale W.; Kirksey, Sanford T.; Kurtz, James L.

doi:10.1021/ic50182a047

Cited by 70 publications

(60 citation statements)

References 51 publications

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“…By electrochemical studies, electronic absorption and electron paramagnetic resonance (EPR) spectroscopy it was confi rmed the reaction involves a Ni(III) intermediate, and it was established by X-ray crystallography that the Ni(II)-peptide product is decarboxylated and hydroxylated at His Cα [206]. Formation of Ni(III) is a common feature in oxidations of square planar Ni(II)-peptide complexes [192]. The crystal structure of [Ni(II)GlyGly-α-OH-Hm] (where Hm is histamine) shows a square planar complex, chelated by the amine terminal nitrogen, two deprotonated peptide nitrogens, and a histidyl imidazole nitrogen.…”

Section: Methodsmentioning

confidence: 99%

“…Peptide complexes of Ni(III) exhibit a variable stability in solution, persisting from seconds to hours [191][192][193][194]. Nickel(III) complexes undergo self-oxidation-reduction, catalyzed by either acid or base [192,195] in which the ligand is oxidized and the metal ion is reduced [196].…”

Section: Redox And/or Catalytic Reactions Involving Nickel(ii) Complexesmentioning

confidence: 99%

“…Nickel(III) complexes undergo self-oxidation-reduction, catalyzed by either acid or base [192,195] in which the ligand is oxidized and the metal ion is reduced [196]. Oxidation of blue [bis(dipeptide)Ni(II)] yields violet-black solutions of Ni(III) complexes which are long-lived species in neutral solution.…”

Section: Redox And/or Catalytic Reactions Involving Nickel(ii) Complexesmentioning

confidence: 99%

See 2 more Smart Citations

Nickel Ion Complexes of Amino Acids and Peptides

Kowalik-Jankowska

Kozłowski

Farkas

et al. 2007

Nickel and Its Surprising Impact in Nature

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Section: Methodsmentioning

confidence: 99%

Section: Redox And/or Catalytic Reactions Involving Nickel(ii) Complexesmentioning

confidence: 99%

Section: Redox And/or Catalytic Reactions Involving Nickel(ii) Complexesmentioning

confidence: 99%

See 1 more Smart Citation

Nickel Ion Complexes of Amino Acids and Peptides

Kowalik-Jankowska

Kozłowski

Farkas

et al. 2007

Nickel and Its Surprising Impact in Nature

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“…Small amounts of this species are produced by direct oxidation of Ni II G n by dissolved oxygen (equation 1). 17,20 and S(IV) oxidation. The balance of S(IV) and O 2 controls the redox cycling process.…”

Section: Mechanismmentioning

confidence: 99%

“…4,5,10,11,14 The S(IV) induced autoxidation of Ni(II) and Co(II) tetraglycine complexes is very fast. 17,20 On the other hand, Cu(II) tetraglycine complexes react slowly but traces (10 -6 mol L -1 ) of Ni(II) and Co(II) ions accelerate the oxidation. 16 The formation of Ni(III) and Co(III) tetraglycine complexes can be followed spectrophotometrically by absorbance changes at 325 and 265 nm, respectively.…”

Section: Introductionmentioning

confidence: 99%

Autoxidation of Ni(II) and Co(II) tetra, penta and hexaglycine complexes accelerated by oxy sulfur radicals

Carvalho

Alipázaga

Lowinsohn

et al. 2006

J. Braz. Chem. Soc.

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A autoxidação dos complexos de Ni(II) e Co(II) com tetra, penta e hexaglicina, em meio de tampão borato, é acelerada por espécies de enxofre(IV) (H 2 SO 3 , HSO 3 -and SO 3 2-). A formação dos complexos de Ni(III) e Co(III) foi acompanhada espectrofotometricamente em 325 e 265 nm, respectivamente. Técnicas eletroquímicas também foram empregadas para caracterizar a geração destes complexos. A velocidade da reação de autoxidação aumenta com a concentração de S(IV) e é máxima em pH ≅ 8,5. O processo é autocatalítico com Ni(III) ou Co(III) atuando como iniciadores, formados pela oxidação espontânea de Ni(II) ou Co(II) pelo oxigênio molecular. A dependência da constante de velocidade de pseudo-primeira ordem com a concentração de sulfito evidenciou possíveis reações paralelas com formação de um complexo com ligantes mistos antes da etapa da oxidação.The autoxidation of Ni(II) and Co(II) complexes with tetra, penta and hexaglycine, in borate medium, is accelerated by sulfur(IV) species (H 2 SO 3 , HSO 3 -and SO 3 2-). The formation of Ni(III) and Co(III) complexes was followed spectrophotometrically at 325 and 265 nm, respectively. Electrochemical techniques were also employed to characterize the generation of these complexes. The autoxidation rate increases with S(IV) concentration and is maximum at pH ≅ 8.5. The process is autocatalytic with Ni(III) or Co(III) acting as initiators, formed by spontaneous oxidation by oxygen. The dependence of the pseudo first order rate constant with sulfite concentration showed evidences of back or parallel reactions with formation of mixed ligand complex prior to the oxidation step.

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