Lifetimes of complexes of the antibiotic x-537a (lasalocid a) with physiological cations in methanol. Determination by NMR using a dissociative shift reagent

C. V. Krishnan, H. L. Friedman, Charles Jr Springer

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19 Citations (Scopus)

Abstract

Using a magnetic resonance method we have determined the lifetimes of the following complexes of X-537A (HX) in methanol solution at 25° C, BaX+, 132 μs; SrX+, 34 μs; CaX+, 24 μs, and KX, 15 μs, each with an estimated uncertainty of 30%. For NaX and LiX the lifetimes are too short to measure by the present method, The lifetime found for BaX+ is considerably shorter than the result obtained by Patel and Shen using a different method. The present method depends upon the broadening of the resonance lines of certain protons in X- due to reactions such as X- + Ba2+ = BaX+, when the resonance of the proton in the "free" X- has been shifted from its normal frequency by Pr(III) which acts via the exchange PrX3 ⇌ PrX+ 2 + X-. To determine the lifetimes of interest the equations for a three-state spin system were derived; under the relevant conditions the final equations take the form of the Swift-Connick equations for a two-state system, with the characteristics of one of the states dependent upon the PrX3 concentration. This dependence is used to extract the life-times from the data in a novel and simple way.

Original languageEnglish (US)
Pages (from-to)23-35
Number of pages13
JournalBiophysical Chemistry
Volume9
Issue number1
DOIs
StatePublished - 1978
Externally publishedYes

Fingerprint

Lasalocid
antibiotics
reagents
Methanol
Cations
Protons
methyl alcohol
Nuclear magnetic resonance
Anti-Bacterial Agents
cations
life (durability)
nuclear magnetic resonance
shift
Magnetic resonance
protons
Uncertainty
Magnetic Resonance Spectroscopy
resonance lines
magnetic resonance

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Physical and Theoretical Chemistry

Cite this

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title = "Lifetimes of complexes of the antibiotic x-537a (lasalocid a) with physiological cations in methanol. Determination by NMR using a dissociative shift reagent",
abstract = "Using a magnetic resonance method we have determined the lifetimes of the following complexes of X-537A (HX) in methanol solution at 25° C, BaX+, 132 μs; SrX+, 34 μs; CaX+, 24 μs, and KX, 15 μs, each with an estimated uncertainty of 30{\%}. For NaX and LiX the lifetimes are too short to measure by the present method, The lifetime found for BaX+ is considerably shorter than the result obtained by Patel and Shen using a different method. The present method depends upon the broadening of the resonance lines of certain protons in X- due to reactions such as X- + Ba2+ = BaX+, when the resonance of the proton in the {"}free{"} X- has been shifted from its normal frequency by Pr(III) which acts via the exchange PrX3 ⇌ PrX+ 2 + X-. To determine the lifetimes of interest the equations for a three-state spin system were derived; under the relevant conditions the final equations take the form of the Swift-Connick equations for a two-state system, with the characteristics of one of the states dependent upon the PrX3 concentration. This dependence is used to extract the life-times from the data in a novel and simple way.",
author = "Krishnan, {C. V.} and Friedman, {H. L.} and Springer, {Charles Jr}",
year = "1978",
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AU - Krishnan, C. V.

AU - Friedman, H. L.

AU - Springer, Charles Jr

PY - 1978

Y1 - 1978

N2 - Using a magnetic resonance method we have determined the lifetimes of the following complexes of X-537A (HX) in methanol solution at 25° C, BaX+, 132 μs; SrX+, 34 μs; CaX+, 24 μs, and KX, 15 μs, each with an estimated uncertainty of 30%. For NaX and LiX the lifetimes are too short to measure by the present method, The lifetime found for BaX+ is considerably shorter than the result obtained by Patel and Shen using a different method. The present method depends upon the broadening of the resonance lines of certain protons in X- due to reactions such as X- + Ba2+ = BaX+, when the resonance of the proton in the "free" X- has been shifted from its normal frequency by Pr(III) which acts via the exchange PrX3 ⇌ PrX+ 2 + X-. To determine the lifetimes of interest the equations for a three-state spin system were derived; under the relevant conditions the final equations take the form of the Swift-Connick equations for a two-state system, with the characteristics of one of the states dependent upon the PrX3 concentration. This dependence is used to extract the life-times from the data in a novel and simple way.

AB - Using a magnetic resonance method we have determined the lifetimes of the following complexes of X-537A (HX) in methanol solution at 25° C, BaX+, 132 μs; SrX+, 34 μs; CaX+, 24 μs, and KX, 15 μs, each with an estimated uncertainty of 30%. For NaX and LiX the lifetimes are too short to measure by the present method, The lifetime found for BaX+ is considerably shorter than the result obtained by Patel and Shen using a different method. The present method depends upon the broadening of the resonance lines of certain protons in X- due to reactions such as X- + Ba2+ = BaX+, when the resonance of the proton in the "free" X- has been shifted from its normal frequency by Pr(III) which acts via the exchange PrX3 ⇌ PrX+ 2 + X-. To determine the lifetimes of interest the equations for a three-state spin system were derived; under the relevant conditions the final equations take the form of the Swift-Connick equations for a two-state system, with the characteristics of one of the states dependent upon the PrX3 concentration. This dependence is used to extract the life-times from the data in a novel and simple way.

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