Mechanistic Information on the Redox Cycling of Nickel(II/III) Complexes in the Presence of Sulfur Oxides and Oxygen. Correlation with DNA Damage Experiments

Lepentsiotis, Vasilios; Domagala, J; Grgić, Irena; Eldik, Rudi van; Muller, James G.; Burrows, Cynthia J.

doi:10.1021/ic981342x

Cited by 44 publications

(33 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The intercept and constant value of k obs at higher S(IV) concentration (in the case of Ni II G 5 and Ni II G 6 autoxidation) in Figure 3( 36 proposed the formation of Ni III L (SO 4 •-) (L=lysylglycylhistidine carboxiamide), where the SO 4 •-radical may coordinate to Ni III L complex. Green et al 37 considered the formation of reactive dimmer species of Ni(II) and Ni(III)Gly 2 HisGly complexes in the oxidative self-decomposition of Ni(III) complex.…”

Section: Mechanismmentioning

confidence: 99%

See 1 more Smart Citation

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.

View full text Add to dashboard Cite

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.

show abstract

Section: Mechanismmentioning

confidence: 99%

“…The balance of S(IV) and O 2 controls the redox cycling process. 2,3,6,8,18,19,[28][29][30][31][32][33][34][35][36] …”

Section: Mechanismmentioning

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.

View full text Add to dashboard Cite

show abstract

“…al. 32 Important aspects of Co(II)/Co(III) complex in the presence of oxygen need to be considered as some possible step in the oxidation. Studies 34 with Co(II) peptides (glygly, gly-ala, ala-gly and ala-ala) showed the formation of dimeric complexes with μ-superoxo bridges.…”

Section: Initiation In the Absence Of Added Ni(ii) Or Co(ii)mentioning

confidence: 99%

Further studies on the synergistic effect of Ni(II) and Co(II) ions on the sulfite induced autoxidation of Cu(II) penta and hexaglycine complexes

Carvalho¹,

Alipázaga²,

Moreno³

et al. 2007

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

A reação de autoxidação dos complexos de Cu(II)/penta e hexaglicina em pH=9 é muito lenta, apresentando um período longo de indução (aproximadamente 4 horas). A presença de S(IV) praticamente não altera a velocidade desta reação. A adição de pequenas quantidades de Ni(II) ou Co(II) aumenta significativamente a velocidade da reação e a eficiência da formação de Cu(III), diminuindo o período de indução para menos de 0,5 s. A constante de velocidade observada para a formação de Cu(III) também depende da concentração de S(IV). A discussão do mecanismo é baseada nas informações disponíveis na literatura e envolve uma cadeia de reações com formação de radicais e um ciclo de oxirredução dos íons metálicos complexados.The autoxidation of Cu(II)/penta and hexaglycine complexes at pH = 9 is very slow showing a large induction period (about 4 h). The presence of S(IV) practically does not affect the rate of this reaction. Addition of small amounts of Ni(II) or Co(II) increases significantly the reaction rate and the effectiveness of Cu(III) formation, the induction period becomes as short as 0.5 s. The observed rate constant for Cu(III) formation also depends on the S(IV) concentration. The mechanism is discussed based on the available literature information and involves a radical chain and redox cycling of the metal ion complexes.

show abstract

“…para oxidar os dois complexos de Ni(II). 7 Muller e colaboradores 9 , em estudos de lesões no DNA induzidas pela autoxidação de sulfito catalisada por alguns complexos de Ni(II), discutiram a reatividade dos diferentes radicais. O radical SO 3…”

Section: Mecanismo Da Autoxidação De S(ivunclassified

“…•'-) oxidam biomoléculas, incluindo lipídios, proteínas e DNA [7][8][9] . Alguns íons metálicos de transição têm um papel importante na formação desses radicais, uma vez que catalisam a oxidação de sulfito pelo oxigênio 10,11 .…”

Section: Introductionunclassified

Lesões em DNA induzidas pela autoxidação de S(IV) na presença de íons metálicos de transição

Moreno¹,

Alipázaga²,

Medeiros³

et al. 2006

Quím. Nova

View full text Add to dashboard Cite

Recebido em 22/6/05; aceito em 18/11/05; publicado na web em 14/6/06 DNA DAMAGE INDUCED BY THE AUTOXIDATION OF S(IV) IN THE PRESENCE OF TRANSITION METAL IONS. The oxidation of sulfite catalyzed by transition metal ions produces reactive oxysulfur species that can damage plasmid and isolated DNA in vitro. Among the four DNA bases, guanine is the most sensitive to one-electron oxidation promoted by the species formed in the autoxidation of sulfite (HSO 5 -, HO • , SO 3 •-, SO 4 •-and SO 5•-) due to its low reduction potential and ability to bind transition metal ions capable to catalyze oxidative processes. Some oxidative DNA lesions are promutagenic and oxidative DNA damage is proposed to play a crucial role in certain human pathologies, including cancer.

show abstract

Mechanistic Information on the Redox Cycling of Nickel(II/III) Complexes in the Presence of Sulfur Oxides and Oxygen. Correlation with DNA Damage Experiments

Cited by 44 publications

References 27 publications

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

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

Further studies on the synergistic effect of Ni(II) and Co(II) ions on the sulfite induced autoxidation of Cu(II) penta and hexaglycine complexes

Lesões em DNA induzidas pela autoxidação de S(IV) na presença de íons metálicos de transição

Contact Info

Product

Resources

About