Solution equilibrium studies on metal complexes of 2,3-dihydroxy-phenylalanine-hydroxamic acid (Dopaha) and models

Catecholate versus hydroxamate coordination in iron(III)-, aluminium(III)- and molybdenum(VI)-Dopaha complexes

E. Farkas, Hajnalka Csóka

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24 Citations (Scopus)

Abstract

Equilibrium results based on pH potentiometric, spectrophotometric and 1H NMR measurements for the complexes of Fe(III), Al(III) and Mo(VI) with 2,3-dihydroxy-phenylalanine-hydroxamic acid (Dopaha) as well as for binary model systems Fe(III)-, Al(III)-, Mo(VI)-acetohydroxamic acid (Aha), -α-alaninehydroxamic acid (α-Alaha) and -1,2-dihydroxy-3,5-benzene-disulphonate (Tiron) and ternary model systems Fe(III)-, Al(III)-, Mo(VI)-Tiron-Aha, are summarized in this paper. The amine-type coordination mode is not detectable with these metal ions at all. Precipitation occurs at pH 3. A ligand-bridged dinuclear species, [(MoO2)2(Dopaha)2]2+, involving mixed-type (catecholate and hydroxamate) coordination modes is formed in the pH range 2.5-5.5. [MoO2A2H2], with catecholate-type coordination, forms above pH 3. On increasing the pH further, deprotonation of the coordinated Dopaha and hydrolytic processes result in the formation of catecholate-coordinated [MoO3AH] and [MoO3A]. MoO4 2- and free Dopaha exist above pH 10.

Original languageEnglish
Pages (from-to)219-226
Number of pages8
JournalJournal of Inorganic Biochemistry
Volume89
Issue number3-4
DOIs
Publication statusPublished - Apr 28 2002

Fingerprint

Hydroxamic Acids
Molybdenum
Coordination Complexes
Aluminum
Phenylalanine
Iron
1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt
Deprotonation
Benzene
Amines
Metal ions
Nuclear magnetic resonance
Ligands
Acids
Metals
Ions
acetohydroxamic acid

Keywords

  • Aluminium(III)
  • Complex
  • Dopa-hydroxamic acid
  • Iron(III)
  • Molybdenum(VI)

ASJC Scopus subject areas

  • Biochemistry
  • Inorganic Chemistry

Cite this

@article{99c7d440c698467782d64c1731f46a75,
title = "Solution equilibrium studies on metal complexes of 2,3-dihydroxy-phenylalanine-hydroxamic acid (Dopaha) and models: Catecholate versus hydroxamate coordination in iron(III)-, aluminium(III)- and molybdenum(VI)-Dopaha complexes",
abstract = "Equilibrium results based on pH potentiometric, spectrophotometric and 1H NMR measurements for the complexes of Fe(III), Al(III) and Mo(VI) with 2,3-dihydroxy-phenylalanine-hydroxamic acid (Dopaha) as well as for binary model systems Fe(III)-, Al(III)-, Mo(VI)-acetohydroxamic acid (Aha), -α-alaninehydroxamic acid (α-Alaha) and -1,2-dihydroxy-3,5-benzene-disulphonate (Tiron) and ternary model systems Fe(III)-, Al(III)-, Mo(VI)-Tiron-Aha, are summarized in this paper. The amine-type coordination mode is not detectable with these metal ions at all. Precipitation occurs at pH 3. A ligand-bridged dinuclear species, [(MoO2)2(Dopaha)2]2+, involving mixed-type (catecholate and hydroxamate) coordination modes is formed in the pH range 2.5-5.5. [MoO2A2H2], with catecholate-type coordination, forms above pH 3. On increasing the pH further, deprotonation of the coordinated Dopaha and hydrolytic processes result in the formation of catecholate-coordinated [MoO3AH] and [MoO3A]. MoO4 2- and free Dopaha exist above pH 10.",
keywords = "Aluminium(III), Complex, Dopa-hydroxamic acid, Iron(III), Molybdenum(VI)",
author = "E. Farkas and Hajnalka Cs{\'o}ka",
year = "2002",
month = "4",
day = "28",
doi = "10.1016/S0162-0134(02)00379-3",
language = "English",
volume = "89",
pages = "219--226",
journal = "Journal of Inorganic Biochemistry",
issn = "0162-0134",
publisher = "Elsevier Inc.",
number = "3-4",

}

TY - JOUR

T1 - Solution equilibrium studies on metal complexes of 2,3-dihydroxy-phenylalanine-hydroxamic acid (Dopaha) and models

T2 - Catecholate versus hydroxamate coordination in iron(III)-, aluminium(III)- and molybdenum(VI)-Dopaha complexes

AU - Farkas, E.

AU - Csóka, Hajnalka

PY - 2002/4/28

Y1 - 2002/4/28

N2 - Equilibrium results based on pH potentiometric, spectrophotometric and 1H NMR measurements for the complexes of Fe(III), Al(III) and Mo(VI) with 2,3-dihydroxy-phenylalanine-hydroxamic acid (Dopaha) as well as for binary model systems Fe(III)-, Al(III)-, Mo(VI)-acetohydroxamic acid (Aha), -α-alaninehydroxamic acid (α-Alaha) and -1,2-dihydroxy-3,5-benzene-disulphonate (Tiron) and ternary model systems Fe(III)-, Al(III)-, Mo(VI)-Tiron-Aha, are summarized in this paper. The amine-type coordination mode is not detectable with these metal ions at all. Precipitation occurs at pH 3. A ligand-bridged dinuclear species, [(MoO2)2(Dopaha)2]2+, involving mixed-type (catecholate and hydroxamate) coordination modes is formed in the pH range 2.5-5.5. [MoO2A2H2], with catecholate-type coordination, forms above pH 3. On increasing the pH further, deprotonation of the coordinated Dopaha and hydrolytic processes result in the formation of catecholate-coordinated [MoO3AH] and [MoO3A]. MoO4 2- and free Dopaha exist above pH 10.

AB - Equilibrium results based on pH potentiometric, spectrophotometric and 1H NMR measurements for the complexes of Fe(III), Al(III) and Mo(VI) with 2,3-dihydroxy-phenylalanine-hydroxamic acid (Dopaha) as well as for binary model systems Fe(III)-, Al(III)-, Mo(VI)-acetohydroxamic acid (Aha), -α-alaninehydroxamic acid (α-Alaha) and -1,2-dihydroxy-3,5-benzene-disulphonate (Tiron) and ternary model systems Fe(III)-, Al(III)-, Mo(VI)-Tiron-Aha, are summarized in this paper. The amine-type coordination mode is not detectable with these metal ions at all. Precipitation occurs at pH 3. A ligand-bridged dinuclear species, [(MoO2)2(Dopaha)2]2+, involving mixed-type (catecholate and hydroxamate) coordination modes is formed in the pH range 2.5-5.5. [MoO2A2H2], with catecholate-type coordination, forms above pH 3. On increasing the pH further, deprotonation of the coordinated Dopaha and hydrolytic processes result in the formation of catecholate-coordinated [MoO3AH] and [MoO3A]. MoO4 2- and free Dopaha exist above pH 10.

KW - Aluminium(III)

KW - Complex

KW - Dopa-hydroxamic acid

KW - Iron(III)

KW - Molybdenum(VI)

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U2 - 10.1016/S0162-0134(02)00379-3

DO - 10.1016/S0162-0134(02)00379-3

M3 - Article

VL - 89

SP - 219

EP - 226

JO - Journal of Inorganic Biochemistry

JF - Journal of Inorganic Biochemistry

SN - 0162-0134

IS - 3-4

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