Increasing the time resolution of dynamic nuclear magnetic resonance spectroscopy through the use of lanthanide shift reagents

Stephen R. Tanny, Miles Pickering, Charles Jr Springer

Research output: Contribution to journalArticle

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Abstract

A method for increasing the time resolution of dynamic nmr spectroscopy is described. This technique involves using a lanthanide shift reagent to cause a continuous change of the nmr time scale through the exchange sensitive region, while the rates of the observed processes remain constant. The method is illustrated and tested with the interaction of trimethyl carbamate (TMC, (H3C)2NC(O)OCH3) with tris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedionato)europium(III) in CCl4 at 27°. The free energy of activation of the isomerization of TMC (which cannot be studied by proton nmr in CCl4 solution alone) is easily obtained. It is found to be 15.5 ± 0.1 kcal/mol, in excellent agreement with a literature value determined in CDCl3 solution. In addition, the free energy of activation for isomerization of TMC bound to the metal chelate is found to be considerably increased. This is reasonable in terms of both electronic and steric factors.

Original languageEnglish (US)
Pages (from-to)6227-6232
Number of pages6
JournalJournal of the American Chemical Society
Volume95
Issue number19
StatePublished - 1973
Externally publishedYes

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Lanthanoid Series Elements
Isomerization
Rare earth elements
Nuclear magnetic resonance spectroscopy
Free energy
Magnetic Resonance Spectroscopy
Chemical activation
Carbamates
Europium
Protons
Spectrum Analysis
Metals
Spectroscopy
tris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6- octanedionato)europium(III)

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Increasing the time resolution of dynamic nuclear magnetic resonance spectroscopy through the use of lanthanide shift reagents. / Tanny, Stephen R.; Pickering, Miles; Springer, Charles Jr.

In: Journal of the American Chemical Society, Vol. 95, No. 19, 1973, p. 6227-6232.

Research output: Contribution to journalArticle

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