Interaction between iron(II) and hydroxamic acids: oxidation of iron(II) to iron(III) by desferrioxamine B under anaerobic conditions

Farkas, Etelka; Enyedy, Éva A.; Zékány, László; Deák, György

doi:10.1016/s0162-0134(00)00197-5

Cited by 62 publications

(58 citation statements)

References 10 publications

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“…The addition of Fe 3+ to the starting complex 11 in the ratio 1:2 11:Fe 3+ , however, prevents the oxidation of Fe 2+ bound to the bipy units. These results agree with data from literature, 40 since it has been well established that Fe 2+ can be easily oxidized to Fe 3+ in the presence of atmospheric oxygen, and that the rates of oxidation are highly dependent on pH and on the nature of the coordinating ligands.These same conditions were also used to perform direct complexation of the hydroxamic acid groups of ligand 4 with Fe 3+ (Scheme 4). Only a band in the visible region was observed (λ max = 426 nm; ε max = 3046 L mol -1 cm -1 ).…”

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confidence: 91%

Inorganic self-assembly through sequential complexation in the formation of bimetallic and trimetallic architectures from multisite ligands based on 5,5'-disubstituted 2,2'-bipyridines

Machado¹,

Mangrich²,

Lehn³

2003

J. Braz. Chem. Soc.

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Dois pré-ligantes 2,2'-bipiridínicos 5,5'-dissubstituídos apresentando em sua estrutura dois ou três sítios de coordenação [5,5'-bis(ácido N-metil-hidroxâmico)-2,2'-bipiridina (4) e 5-metil-5'-(ácido N-metil-hidroxâmico)-2,2-bipiridina (10)] foram sintetizados. Estes ligantes foram empregados no estudo de uma estratégia de automontagem por complexação seqüencial. De acordo com este conceito, o primeiro metal adicionado organiza os substituintes-ligantes das posições 5,5' para a complexação do segundo íon metálico adicionado seqüencialmente. A adição de Fe 2+ a uma solução contendo 4 levou à formação do complexo Fe 2+ -tris(bipiridil). A adição de Fe 3+ a este complexo rendeu uma arquitetura trimetálica. O ligante 10 levou à formação de uma mistura de arquiteturas bimetálicas pela adição seqüencial de íons Fe 2+ e Fe 3+ . No entanto, quando a ordem de adição foi alterada, somente um complexo bimetálico foi obtido. Isto se deve ao fato de que o primeiro metal adicionado (Fe 3+ ) age como um molde, organizando os ligantes bipiridínicos e pré-formando uma cavidade adequada para o íon Fe 2+ .Two multisite 5,5'-disubstituted 2,2'-bipyridine ligands containing N-methyl hydroxamic acids as substituents [5,5'-bis(N-methylhydroxamic)-2,2'-bipyridine (4) and 5-methyl-5'-(Nmethylhydroxamic)-2,2-bipyridine (10)] were synthesized. These ligands were used in order to illustrate the strategy of self-assembly through sequential complexation. According to this concept, the first metal added organizes the ligands disposed in 5,5'-positions to accomodate the second metal ion that is sequentially added. Thus, addition of Fe 2+ to a solution of 4 led to a Fe 2+ -tris(bipyridine) complex. Addition of Fe 3+ to this solution yielded a trimetallic architecture, which was characterized. Ligand 10 yielded a mixture of bimetallic architectures through complexation with Fe 2+ followed by Fe 3+ ions. However, if the order of metal addition is changed, only one bimetallic complex is obtained. This is due to the fact that the first metal ion added (Fe 3+ ) acts as a template, organizing the bipyridine ligands and preforming an adequate cavity for the Fe 2+ ion.Keywords: inorganic self-assembly, sequential ligands, sequential complexation, metalloexoreceptors IntroductionSelf-assembly of inorganic architectures from programmed components has been an extensively investigated field of supramolecular chemistry in recent years. [1][2][3][4][5][6] Such processes involve the design of programmed supramolecular species, which are spontaneously formed from carefully constructed ligands and metal ions able to read the binding sites according to their coordination algorithm. 1,2,6 This strategy has allowed the synthesis of a great variety of inorganic architectures, 1-6 such as double-7 and triple-helical 8 complexes, rack-, 9 grid-10 and cagetype 11 arrays of metal ions synthesized by our own group. The design of ligands containing different coordination sites has spontaneously yielded structures having different metal ions at specific locations, as in h...

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confidence: 91%

Inorganic self-assembly through sequential complexation in the formation of bimetallic and trimetallic architectures from multisite ligands based on 5,5'-disubstituted 2,2'-bipyridines

Machado¹,

Mangrich²,

Lehn³

2003

J. Braz. Chem. Soc.

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“…In addition to what is imparted by multidentate binding, the stability of Fe(III)-siderophore complexes is rationalized by noting that the hard oxygen atoms in siderophore moieties interact strongly with the hard Fe(III) ion (Hernlem et al 1999). Siderophore complexes with the softer Fe(II) ion generally have much lower stability constants, and Fe(II)-hydroxamate siderophore complexes in particular may be unstable with respect to oxidation or auto-oxidation (Farkas et al 2001;Kim et al 2009). …”

Section: Stability and Exchange Of Mn And Fe Siderophore Complexesmentioning

confidence: 99%

Coupled biogeochemical cycling of iron and manganese as mediated by microbial siderophores

2009

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Siderophores, biogenic chelating agents that facilitate Fe(III) uptake through the formation of strong complexes, also form strong complexes with Mn(III) and exhibit high reactivity with Mn (hydr)oxides, suggesting a pathway by which Mn may disrupt Fe uptake. In this review, we evaluate the major biogeochemical mechanisms by which Fe and Mn may interact through reactions with microbial siderophores: competition for a limited pool of siderophores, sorption of siderophores and metal-siderophore complexes to mineral surfaces, and competitive metal-siderophore complex formation through parallel mineral dissolution pathways. This rich interweaving of chemical processes gives rise to an intricate tapestry of interactions, particularly in respect to the biogeochemical cycling of Fe and Mn in marine ecosystems.

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“…[5] Even under anaerobic conditions, above pH 4, in the iron()-desferrioxamine B system, oxidation of iron() to iron() by hydroxamate occurs to give the iron()-desferrioxamine B complex and desferrioxamine B monoamide. [5] The iron siderophore complex, once inside the cell, undergoes reduction, releasing iron and making it accessible to metabolic demands within the cell. [6] A remarkable feature of siderophores, which is crucial to their function, is their ability to selectively bind iron() over other metal ions, which may be ''poisonous''.…”

Section: Introductionmentioning

confidence: 99%

“…[91] In doing so, we effectively used ruthenium() as a tool to abstract NO from hydroxamic acids. A similar reaction of hydroxamic acids with K 3 [Fe(CN) 6 ] to give [Fe(CN) 5 ) and no absorption at 1730 cm…”

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confidence: 99%

Hydroxamic Acids − An Intriguing Family of Enzyme Inhibitors and Biomedical Ligands

2004

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Interaction between iron(II) and hydroxamic acids: oxidation of iron(II) to iron(III) by desferrioxamine B under anaerobic conditions

Cited by 62 publications

References 10 publications

Inorganic self-assembly through sequential complexation in the formation of bimetallic and trimetallic architectures from multisite ligands based on 5,5'-disubstituted 2,2'-bipyridines

Inorganic self-assembly through sequential complexation in the formation of bimetallic and trimetallic architectures from multisite ligands based on 5,5'-disubstituted 2,2'-bipyridines

Coupled biogeochemical cycling of iron and manganese as mediated by microbial siderophores

Hydroxamic Acids − An Intriguing Family of Enzyme Inhibitors and Biomedical Ligands

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