The first automated 470.59 MHz19F NMR-controlled titration: dissociation constants and ion-specific chemical shifts of 2-amino-4-fluoro 2-methylpent-4-enoic acid

Autor:	K. W. Laue, M. Lübke, C. G. Pfaff, C. E. Uhlemann, Gerhard Hägele, Günter Haufe
Rok vydání:	2002
Předmět:	Dissociation constant Deprotonation Chemistry Chemical shift Analytical chemistry Proton NMR General Materials Science Titration General Chemistry Nuclear magnetic resonance spectroscopy Fluorine-19 NMR Ion
Zdroj:	Magnetic Resonance in Chemistry. 40:573-580
ISSN:	0749-1581
Popis:	2-Amino-4-fluoro-2-methylpent-4-enoic acid, obtained as a 1 : 1 salt with trifluoro-acetic acid, was characterized by 1H and 19F high-resolution NMR spectroscopy. High-precision potentiometry led to the dissociation constants pK = 1.879 and pK = 9.054. The first automated 470.59 MHz 19F NMR-controlled titration yielded the dynamic chemical shift 〈δF〉 as a function of pcH or τ and the ion-specific chemical shifts: δF(H2L+) = −94.81 ppm, δF(HL) = −94.21 ppm, δF(L−) = −92.45 ppm. The deprotonation gradients were found to be Δ1 = −0.60 ppm and Δ2 = −1.76 ppm. Copyright © 2002 John Wiley & Sons, Ltd.
Databáze:	OpenAIRE
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