Chemical shifts and protonation shifts in carbon-13 nuclear magnetic resonance studies of aqueous amines

Sarneski, Joseph E.; Surprenant, Henry L.; Molen, Frederick K.; Reilley, Charles N.

doi:10.1021/ac60363a010

Cited by 186 publications

(72 citation statements)

References 34 publications

(27 reference statements)

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“…The assignment of (25). It may be noted that the precision of the values the resonances (22) was unambiguous and the experi-obtained here from NMR data is comparable to the mental chemical shifts are in good agreement with those calculated using the semiempirical formula of Sarneski et al (24).…”

Section: Basicity Constants and Chemical Shiftssupporting

confidence: 86%

Nuclear Magnetic Resonance as a Tool for Determining Protonation Constants of Natural Polyprotic Bases in Solution

Frassineti

Ghelli

Gans

et al. 1995

Analytical Biochemistry

436

409

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Section: Basicity Constants and Chemical Shiftssupporting

confidence: 86%

Nuclear Magnetic Resonance as a Tool for Determining Protonation Constants of Natural Polyprotic Bases in Solution

Frassineti

Ghelli

Gans

et al. 1995

Analytical Biochemistry

436

409

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“…[35] In diethylamine, the 13 C α protonation shift is small (only -0.60 ppm), whereas the β protonation shift is significant (-3.22 ppm). In diisopropylamine, the 13 C α Figure 6.…”

Section: H and 13 C Nmr Analysismentioning

confidence: 96%

“…The chemical shift changes between the protonated forms and the neutral forms have been termed "protonation shift", [35] i.e., δ protonated -δ neutral . A downfield chemical shift displacement upon protonation corresponds to a positive value.…”

Section: H and 13 C Nmr Analysismentioning

confidence: 99%

pK_a‐Determination and Conformational Studies by NMR Spectroscopy of D‐Altrose‐Containing and other Pseudodisaccharides as Glycosidase Inhibitor Candidates

et al. 2011

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The pKa values of six amine‐linked pseudodisaccharides have been determined by using an NMR‐based titration method. The pKa varies significantly depending on the linkage position and is inversely correlated with the number of electronegative groups in the β‐position to the amino group. Four of the pseudodisaccharides contain α‐altroside moieties, the conformations of which were determined in the protonated and neutral states, again by using NMR techniques. In the neutral state, 2‐amino‐2‐deoxyaltrosides and 3‐amino‐3‐deoxyaltrosides were both found to occupy 4C1 and OS2 conformations. On protonation, little change in the population distribution was seen for the 3‐amino‐3‐deoxyaltrosides, but for the 2‐amino‐2‐deoxyaltrosides, a shift in equilibrium position towards the skew conformer (more than 80 % populated) takes place, and also a small amount of the other chair conformer (i.e., 1C4, approximately 10 % populated) was observed. 3‐Amino‐3‐deoxyaltrosides have been shown to act as glycosidase inhibitors and insights into conformational equilibria as a function of protonation state should facilitate the design of better glycosidase inhibitors based on flexible monosaccharide amines.

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“…However, the behaviour of o-B232 is slightly different: the first two protonation processes occur with constants significantly larger than those found for the acyclic 232 ligand. This increased basicity in the early protonation stages can be explained by the formation of intramolecular hydrogen bonds between couples of protonated and unprotonated nitrogen atoms, as revealed by NMR studies at different pH values [21] and by the crystal structure of the [H 2 (o-B232)](picrate) 2 ·1/2(C 3 H 6 O) molecule.…”

Section: Synthesis and Protonation Of The Cyclophanesmentioning

confidence: 97%

Equilibrium and Kinetic Properties of Cu^II Cyclophane Complexes: The Effect of Changes in the Macrocyclic Cavity Caused by Changes in the Substitution at the Aromatic Ring

et al. 2008

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The o-B232, m-B232 and p-B232 cyclophanes result from attaching the terminal amine groups of 1,4,8,11-tetraazaundecane (232) to the benzylic carbons of the corresponding o-, m-or p-xylanes. The cavity size of these cyclophanes changes moderately as a consequence of the substitution at the aromatic ring. The effects caused by these changes on the equilibrium constants for protonation and Cu II complex formation of the cyclophanes are analyzed and compared with those of the noncyclic 232 polyamine. All three cyclophanes form mononuclear complexes, but only o-B232 is able to coordinate to Cu II through the four amine groups simultaneously, whereas m-B232 and p-B232 can only use three nitrogen donors. The larger cavity and higher flexibility of the latter two cyclophanes allow them to form stable dinuclear Cu II complexes. The kinetics of the acid-promoted dissociation of Cu II from its mono-and dinuclear complexes has also been studied and the results indicate the existence of large differences in the kinetic properties for the com-

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Chemical shifts and protonation shifts in carbon-13 nuclear magnetic resonance studies of aqueous amines

Cited by 186 publications

References 34 publications

Nuclear Magnetic Resonance as a Tool for Determining Protonation Constants of Natural Polyprotic Bases in Solution

Nuclear Magnetic Resonance as a Tool for Determining Protonation Constants of Natural Polyprotic Bases in Solution

pK_a‐Determination and Conformational Studies by NMR Spectroscopy of D‐Altrose‐Containing and other Pseudodisaccharides as Glycosidase Inhibitor Candidates

Equilibrium and Kinetic Properties of Cu^II Cyclophane Complexes: The Effect of Changes in the Macrocyclic Cavity Caused by Changes in the Substitution at the Aromatic Ring

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Chemical shifts and protonation shifts in carbon-13 nuclear magnetic resonance studies of aqueous amines

Cited by 186 publications

References 34 publications

Nuclear Magnetic Resonance as a Tool for Determining Protonation Constants of Natural Polyprotic Bases in Solution

Nuclear Magnetic Resonance as a Tool for Determining Protonation Constants of Natural Polyprotic Bases in Solution

pKa‐Determination and Conformational Studies by NMR Spectroscopy of D‐Altrose‐Containing and other Pseudodisaccharides as Glycosidase Inhibitor Candidates

Equilibrium and Kinetic Properties of CuII Cyclophane Complexes: The Effect of Changes in the Macrocyclic Cavity Caused by Changes in the Substitution at the Aromatic Ring

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pK_a‐Determination and Conformational Studies by NMR Spectroscopy of D‐Altrose‐Containing and other Pseudodisaccharides as Glycosidase Inhibitor Candidates

Equilibrium and Kinetic Properties of Cu^II Cyclophane Complexes: The Effect of Changes in the Macrocyclic Cavity Caused by Changes in the Substitution at the Aromatic Ring