Acid-base properties and copper(II) complexes of dipeptides containing histidine and additional chelating bis(imidazol-2-yl) residues

K. Ősz, K. Várnagy, H. Süli-Vargha, Antal Csámpay, Daniele Sanna, Giovanni Micera, I. Sóvágó

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Abstract

Copper(II) complexes of dipeptides of histidine containing additional chelating bis(imidazol-2-yl) agent at the C-termini (PheHis-BIMA [N-phenylalanyl-histidyl-bis(imidazol-2-yl)methylamine] and HisPhe-BIMA [N-histidyl-phenylalanyl-bis(imidazol-2-yl)methylamine]) were studied by potentiometric, UV-Visible and Electron Paramagnetic Resonance (EPR) techniques. The imidazole nitrogen donor atoms of the bis(imidazol-2-yl)methyl group are described as the primary metal binding sites forming stable mono- and bis(ligand) complexes at acidic pH. The formation of a ligand-bridged dinuclear complex [Cu2L2]4+ is detected in equimolar solutions of copper(II) and HisPhe-BIMA. The coordination isomers of the dinuclear complex are described via the metal binding of the bis(imidazol-2-yl)methyl, amino-carbonyl and amino-imidazole(His) functions. In the case of the copper(II)-PheHis-BIMA system the [NH2, N -(amide), N(Im)] tridentate coordination of the ligand is favoured and results in the formation of di- and trinuclear complexes [Cu 2H-1L]3+ and [Cu3H -2L2]4+ in equimolar solutions. The presence of these coordination modes shifts the formation of "tripeptide-like" ([NH2, N-, N-, N(Im)]-coordinated) [CuH -2L] complexes into alkaline pH range as compared to other dipeptide derivatives of bis(imidazol-2-yl) ligands. Although there are different types of imidazoles in these ligands, the deprotonation and coordination of the pyrrole-type N(1)H groups does not occur below pH 10.

Original languageEnglish
Pages (from-to)24-32
Number of pages9
JournalJournal of Inorganic Biochemistry
Volume98
Issue number1
DOIs
Publication statusPublished - Jan 2004

Fingerprint

Dipeptides
Chelation
Histidine
Copper
Ligands
Acids
Metals
Imidazoles
Deprotonation
Pyrroles
Electron Spin Resonance Spectroscopy
Amides
Isomers
Paramagnetic resonance
Nitrogen
Binding Sites
Derivatives
Atoms
methylamine
imidazole

Keywords

  • Copper(II)
  • Dipeptide
  • Histidine
  • Imidazole
  • Potentiometry

ASJC Scopus subject areas

  • Biochemistry
  • Inorganic Chemistry

Cite this

@article{14decb196d09422aadbc462e0b4ac6b7,
title = "Acid-base properties and copper(II) complexes of dipeptides containing histidine and additional chelating bis(imidazol-2-yl) residues",
abstract = "Copper(II) complexes of dipeptides of histidine containing additional chelating bis(imidazol-2-yl) agent at the C-termini (PheHis-BIMA [N-phenylalanyl-histidyl-bis(imidazol-2-yl)methylamine] and HisPhe-BIMA [N-histidyl-phenylalanyl-bis(imidazol-2-yl)methylamine]) were studied by potentiometric, UV-Visible and Electron Paramagnetic Resonance (EPR) techniques. The imidazole nitrogen donor atoms of the bis(imidazol-2-yl)methyl group are described as the primary metal binding sites forming stable mono- and bis(ligand) complexes at acidic pH. The formation of a ligand-bridged dinuclear complex [Cu2L2]4+ is detected in equimolar solutions of copper(II) and HisPhe-BIMA. The coordination isomers of the dinuclear complex are described via the metal binding of the bis(imidazol-2-yl)methyl, amino-carbonyl and amino-imidazole(His) functions. In the case of the copper(II)-PheHis-BIMA system the [NH2, N -(amide), N(Im)] tridentate coordination of the ligand is favoured and results in the formation of di- and trinuclear complexes [Cu 2H-1L]3+ and [Cu3H -2L2]4+ in equimolar solutions. The presence of these coordination modes shifts the formation of {"}tripeptide-like{"} ([NH2, N-, N-, N(Im)]-coordinated) [CuH -2L] complexes into alkaline pH range as compared to other dipeptide derivatives of bis(imidazol-2-yl) ligands. Although there are different types of imidazoles in these ligands, the deprotonation and coordination of the pyrrole-type N(1)H groups does not occur below pH 10.",
keywords = "Copper(II), Dipeptide, Histidine, Imidazole, Potentiometry",
author = "K. Ősz and K. V{\'a}rnagy and H. S{\"u}li-Vargha and Antal Cs{\'a}mpay and Daniele Sanna and Giovanni Micera and I. S{\'o}v{\'a}g{\'o}",
year = "2004",
month = "1",
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language = "English",
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TY - JOUR

T1 - Acid-base properties and copper(II) complexes of dipeptides containing histidine and additional chelating bis(imidazol-2-yl) residues

AU - Ősz, K.

AU - Várnagy, K.

AU - Süli-Vargha, H.

AU - Csámpay, Antal

AU - Sanna, Daniele

AU - Micera, Giovanni

AU - Sóvágó, I.

PY - 2004/1

Y1 - 2004/1

N2 - Copper(II) complexes of dipeptides of histidine containing additional chelating bis(imidazol-2-yl) agent at the C-termini (PheHis-BIMA [N-phenylalanyl-histidyl-bis(imidazol-2-yl)methylamine] and HisPhe-BIMA [N-histidyl-phenylalanyl-bis(imidazol-2-yl)methylamine]) were studied by potentiometric, UV-Visible and Electron Paramagnetic Resonance (EPR) techniques. The imidazole nitrogen donor atoms of the bis(imidazol-2-yl)methyl group are described as the primary metal binding sites forming stable mono- and bis(ligand) complexes at acidic pH. The formation of a ligand-bridged dinuclear complex [Cu2L2]4+ is detected in equimolar solutions of copper(II) and HisPhe-BIMA. The coordination isomers of the dinuclear complex are described via the metal binding of the bis(imidazol-2-yl)methyl, amino-carbonyl and amino-imidazole(His) functions. In the case of the copper(II)-PheHis-BIMA system the [NH2, N -(amide), N(Im)] tridentate coordination of the ligand is favoured and results in the formation of di- and trinuclear complexes [Cu 2H-1L]3+ and [Cu3H -2L2]4+ in equimolar solutions. The presence of these coordination modes shifts the formation of "tripeptide-like" ([NH2, N-, N-, N(Im)]-coordinated) [CuH -2L] complexes into alkaline pH range as compared to other dipeptide derivatives of bis(imidazol-2-yl) ligands. Although there are different types of imidazoles in these ligands, the deprotonation and coordination of the pyrrole-type N(1)H groups does not occur below pH 10.

AB - Copper(II) complexes of dipeptides of histidine containing additional chelating bis(imidazol-2-yl) agent at the C-termini (PheHis-BIMA [N-phenylalanyl-histidyl-bis(imidazol-2-yl)methylamine] and HisPhe-BIMA [N-histidyl-phenylalanyl-bis(imidazol-2-yl)methylamine]) were studied by potentiometric, UV-Visible and Electron Paramagnetic Resonance (EPR) techniques. The imidazole nitrogen donor atoms of the bis(imidazol-2-yl)methyl group are described as the primary metal binding sites forming stable mono- and bis(ligand) complexes at acidic pH. The formation of a ligand-bridged dinuclear complex [Cu2L2]4+ is detected in equimolar solutions of copper(II) and HisPhe-BIMA. The coordination isomers of the dinuclear complex are described via the metal binding of the bis(imidazol-2-yl)methyl, amino-carbonyl and amino-imidazole(His) functions. In the case of the copper(II)-PheHis-BIMA system the [NH2, N -(amide), N(Im)] tridentate coordination of the ligand is favoured and results in the formation of di- and trinuclear complexes [Cu 2H-1L]3+ and [Cu3H -2L2]4+ in equimolar solutions. The presence of these coordination modes shifts the formation of "tripeptide-like" ([NH2, N-, N-, N(Im)]-coordinated) [CuH -2L] complexes into alkaline pH range as compared to other dipeptide derivatives of bis(imidazol-2-yl) ligands. Although there are different types of imidazoles in these ligands, the deprotonation and coordination of the pyrrole-type N(1)H groups does not occur below pH 10.

KW - Copper(II)

KW - Dipeptide

KW - Histidine

KW - Imidazole

KW - Potentiometry

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DO - 10.1016/j.jinorgbio.2003.09.009

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AN - SCOPUS:0344234445

VL - 98

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JO - Journal of Inorganic Biochemistry

JF - Journal of Inorganic Biochemistry

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