Microspeciation in the copper(II)-L-histidylglycine system. An ESR study by the two-dimensional computer simulation method

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Twelve ESR-active (and one inactive) copper(II) complexes of L-histidylglycine (HL) were characterized via their formation (micro)constants and ESR parameters obtained by two-dimensional ESR spectroscopic evaluation in aqueous solution. In strongly acidic media, the ligand is coordinated through its N-terminal donor groups: the complex [CuLH2]3+ involves monodentate imidazole binding, whereas [CuLH]2+ involves bidentate ligation through the amino and imidazole N atoms. This histamine-like bonding mode also predominates in the isomers of [CuL2], formed at ligand excess near pH 7: in the major 4N isomer, both ligands occupy two equatorial sites, while in the 3N isomer, the second dipeptide is coordinated equatorially by the amino and axially by the imidazole groups. At above pH 3-4, deprotonation of the peptide group also starts: in ≈60% of the molecules of [CuL]+, the peptide group is deprotonated, while in the minor isomer histamine-like coordination occurs. At higher pH, the active dimer [Cu2L2H-2], the mixed hydroxo complexes (the inactive [Cu2L2H-3]- and the active [CuLH-2]-), and the bis complexes [CuL2H]+ and [CuL2H-1]- all involve tridentate equatorial ligation of the backbone by the amino and deprotonated peptide N and the carboxylate O atoms. In the active dimer, the neutral imidazole groups form bridges between CuLH-1 units. In [CuL2H]+, the second ligand is bound equatorially via its imidazole group; in [CuL2H-1]-, the L ligand occupies the fourth equatorial site and an axial site through its amino and imidazole N atoms, respectively.

Original languageEnglish
Pages (from-to)3483-3490
Number of pages8
JournalInorganic Chemistry
Volume41
Issue number13
DOIs
Publication statusPublished - Jul 1 2002

Fingerprint

histidylglycine
imidazoles
Paramagnetic resonance
Copper
computerized simulation
Isomers
copper
Ligands
Computer simulation
isomers
ligands
histamines
peptides
Dimers
Atoms
Histamine
Peptides
dimers
atoms
Deprotonation

ASJC Scopus subject areas

  • Inorganic Chemistry

Cite this

@article{9cef75137b574e4984084d6107d2e6c1,
title = "Microspeciation in the copper(II)-L-histidylglycine system. An ESR study by the two-dimensional computer simulation method",
abstract = "Twelve ESR-active (and one inactive) copper(II) complexes of L-histidylglycine (HL) were characterized via their formation (micro)constants and ESR parameters obtained by two-dimensional ESR spectroscopic evaluation in aqueous solution. In strongly acidic media, the ligand is coordinated through its N-terminal donor groups: the complex [CuLH2]3+ involves monodentate imidazole binding, whereas [CuLH]2+ involves bidentate ligation through the amino and imidazole N atoms. This histamine-like bonding mode also predominates in the isomers of [CuL2], formed at ligand excess near pH 7: in the major 4N isomer, both ligands occupy two equatorial sites, while in the 3N isomer, the second dipeptide is coordinated equatorially by the amino and axially by the imidazole groups. At above pH 3-4, deprotonation of the peptide group also starts: in ≈60{\%} of the molecules of [CuL]+, the peptide group is deprotonated, while in the minor isomer histamine-like coordination occurs. At higher pH, the active dimer [Cu2L2H-2], the mixed hydroxo complexes (the inactive [Cu2L2H-3]- and the active [CuLH-2]-), and the bis complexes [CuL2H]+ and [CuL2H-1]- all involve tridentate equatorial ligation of the backbone by the amino and deprotonated peptide N and the carboxylate O atoms. In the active dimer, the neutral imidazole groups form bridges between CuLH-1 units. In [CuL2H]+, the second ligand is bound equatorially via its imidazole group; in [CuL2H-1]-, the L ligand occupies the fourth equatorial site and an axial site through its amino and imidazole N atoms, respectively.",
author = "T. Szab{\'o}-Pl{\'a}nka and N. Nagy and A. Rockenbauer and L. Korecz",
year = "2002",
month = "7",
day = "1",
doi = "10.1021/ic0113092",
language = "English",
volume = "41",
pages = "3483--3490",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "13",

}

TY - JOUR

T1 - Microspeciation in the copper(II)-L-histidylglycine system. An ESR study by the two-dimensional computer simulation method

AU - Szabó-Plánka, T.

AU - Nagy, N.

AU - Rockenbauer, A.

AU - Korecz, L.

PY - 2002/7/1

Y1 - 2002/7/1

N2 - Twelve ESR-active (and one inactive) copper(II) complexes of L-histidylglycine (HL) were characterized via their formation (micro)constants and ESR parameters obtained by two-dimensional ESR spectroscopic evaluation in aqueous solution. In strongly acidic media, the ligand is coordinated through its N-terminal donor groups: the complex [CuLH2]3+ involves monodentate imidazole binding, whereas [CuLH]2+ involves bidentate ligation through the amino and imidazole N atoms. This histamine-like bonding mode also predominates in the isomers of [CuL2], formed at ligand excess near pH 7: in the major 4N isomer, both ligands occupy two equatorial sites, while in the 3N isomer, the second dipeptide is coordinated equatorially by the amino and axially by the imidazole groups. At above pH 3-4, deprotonation of the peptide group also starts: in ≈60% of the molecules of [CuL]+, the peptide group is deprotonated, while in the minor isomer histamine-like coordination occurs. At higher pH, the active dimer [Cu2L2H-2], the mixed hydroxo complexes (the inactive [Cu2L2H-3]- and the active [CuLH-2]-), and the bis complexes [CuL2H]+ and [CuL2H-1]- all involve tridentate equatorial ligation of the backbone by the amino and deprotonated peptide N and the carboxylate O atoms. In the active dimer, the neutral imidazole groups form bridges between CuLH-1 units. In [CuL2H]+, the second ligand is bound equatorially via its imidazole group; in [CuL2H-1]-, the L ligand occupies the fourth equatorial site and an axial site through its amino and imidazole N atoms, respectively.

AB - Twelve ESR-active (and one inactive) copper(II) complexes of L-histidylglycine (HL) were characterized via their formation (micro)constants and ESR parameters obtained by two-dimensional ESR spectroscopic evaluation in aqueous solution. In strongly acidic media, the ligand is coordinated through its N-terminal donor groups: the complex [CuLH2]3+ involves monodentate imidazole binding, whereas [CuLH]2+ involves bidentate ligation through the amino and imidazole N atoms. This histamine-like bonding mode also predominates in the isomers of [CuL2], formed at ligand excess near pH 7: in the major 4N isomer, both ligands occupy two equatorial sites, while in the 3N isomer, the second dipeptide is coordinated equatorially by the amino and axially by the imidazole groups. At above pH 3-4, deprotonation of the peptide group also starts: in ≈60% of the molecules of [CuL]+, the peptide group is deprotonated, while in the minor isomer histamine-like coordination occurs. At higher pH, the active dimer [Cu2L2H-2], the mixed hydroxo complexes (the inactive [Cu2L2H-3]- and the active [CuLH-2]-), and the bis complexes [CuL2H]+ and [CuL2H-1]- all involve tridentate equatorial ligation of the backbone by the amino and deprotonated peptide N and the carboxylate O atoms. In the active dimer, the neutral imidazole groups form bridges between CuLH-1 units. In [CuL2H]+, the second ligand is bound equatorially via its imidazole group; in [CuL2H-1]-, the L ligand occupies the fourth equatorial site and an axial site through its amino and imidazole N atoms, respectively.

UR - http://www.scopus.com/inward/record.url?scp=0036628666&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0036628666&partnerID=8YFLogxK

U2 - 10.1021/ic0113092

DO - 10.1021/ic0113092

M3 - Article

C2 - 12079468

AN - SCOPUS:0036628666

VL - 41

SP - 3483

EP - 3490

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 13

ER -