Effect of -NH2⇌H2O proton exchange on the paramagnetic relaxation of water protons. 1. Nuclear magnetic resonance study of the copper(II)-glycine system

I. Nagypál, E. Farkas, Ferenc Debreczeni, Arthur Gergely

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Abstract

Fast proton- and ligand-exchange processes have studied in the copper(II)-glycine system by measuring the transverse relaxation time of the water protons. When the experiments were carried out over wide pH and concentration ranges, it was found that at >0.001 M copper(II) concentration the experimental data could not be explained by considering the effects of τB and T2B alone. To explain this deviation, it was assumed that at higher copper(II) concentration the rate of the ligand exchange becomes comparable with the rate of -NH2 ⇌ H2O proton exchange in the diamagnetic environment. With the above assumption the results could be evaluated within experimental error. It was possible to obtain information on the T2B values, the ligand-exchange rate constants, and the -NH2 ⇌ H2O proton-exchange rate constants. The advantages and disadvantages, and the possibilities and limitations of this method (suitable for the simultaneous study of proton exchange between dia- and paramagnetic environments and within a diamagnetic environment) are briefly outlined.

Original languageEnglish
Pages (from-to)1548-1553
Number of pages6
JournalJournal of Physical Chemistry
Volume82
Issue number13
Publication statusPublished - 1978

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glycine
Glycine
Protons
Amino acids
Copper
Ion exchange
Nuclear magnetic resonance
copper
nuclear magnetic resonance
protons
Water
water
Ligands
ligands
Rate constants
Relaxation time
relaxation time
deviation
Experiments

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

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abstract = "Fast proton- and ligand-exchange processes have studied in the copper(II)-glycine system by measuring the transverse relaxation time of the water protons. When the experiments were carried out over wide pH and concentration ranges, it was found that at >0.001 M copper(II) concentration the experimental data could not be explained by considering the effects of τB and T2B alone. To explain this deviation, it was assumed that at higher copper(II) concentration the rate of the ligand exchange becomes comparable with the rate of -NH2 ⇌ H2O proton exchange in the diamagnetic environment. With the above assumption the results could be evaluated within experimental error. It was possible to obtain information on the T2B values, the ligand-exchange rate constants, and the -NH2 ⇌ H2O proton-exchange rate constants. The advantages and disadvantages, and the possibilities and limitations of this method (suitable for the simultaneous study of proton exchange between dia- and paramagnetic environments and within a diamagnetic environment) are briefly outlined.",
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T1 - Effect of -NH2⇌H2O proton exchange on the paramagnetic relaxation of water protons. 1. Nuclear magnetic resonance study of the copper(II)-glycine system

AU - Nagypál, I.

AU - Farkas, E.

AU - Debreczeni, Ferenc

AU - Gergely, Arthur

PY - 1978

Y1 - 1978

N2 - Fast proton- and ligand-exchange processes have studied in the copper(II)-glycine system by measuring the transverse relaxation time of the water protons. When the experiments were carried out over wide pH and concentration ranges, it was found that at >0.001 M copper(II) concentration the experimental data could not be explained by considering the effects of τB and T2B alone. To explain this deviation, it was assumed that at higher copper(II) concentration the rate of the ligand exchange becomes comparable with the rate of -NH2 ⇌ H2O proton exchange in the diamagnetic environment. With the above assumption the results could be evaluated within experimental error. It was possible to obtain information on the T2B values, the ligand-exchange rate constants, and the -NH2 ⇌ H2O proton-exchange rate constants. The advantages and disadvantages, and the possibilities and limitations of this method (suitable for the simultaneous study of proton exchange between dia- and paramagnetic environments and within a diamagnetic environment) are briefly outlined.

AB - Fast proton- and ligand-exchange processes have studied in the copper(II)-glycine system by measuring the transverse relaxation time of the water protons. When the experiments were carried out over wide pH and concentration ranges, it was found that at >0.001 M copper(II) concentration the experimental data could not be explained by considering the effects of τB and T2B alone. To explain this deviation, it was assumed that at higher copper(II) concentration the rate of the ligand exchange becomes comparable with the rate of -NH2 ⇌ H2O proton exchange in the diamagnetic environment. With the above assumption the results could be evaluated within experimental error. It was possible to obtain information on the T2B values, the ligand-exchange rate constants, and the -NH2 ⇌ H2O proton-exchange rate constants. The advantages and disadvantages, and the possibilities and limitations of this method (suitable for the simultaneous study of proton exchange between dia- and paramagnetic environments and within a diamagnetic environment) are briefly outlined.

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