Oxygen-17 NMR spectroscopy: Basic principles and applications (part II)

Gerothanassis, Ioannis P.

doi:10.1016/j.pnmrs.2009.12.001

Cited by 105 publications

(43 citation statements)

References 1,040 publications

(595 reference statements)

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“…For δ O1 , the calculated chemical shift difference was actually only marginal, 8.3 ppm, given the breadth of the chemical shift range for 17 O and the difficulty in measuring δ O accurately due to the large breadth of the 17 O NMR signals (of the order of several ppm depending on B 0 , etc.). However, for δ O3/4 , the calculated chemical shift difference was a sizeable 23.4 ppm, in line with expectations [28,29] for differences between primary and secondary alcohols. Moreover, the chemical shift difference between O-1 and O-3/4 contrasts nicely in the two compounds, 80.4 ppm for compound 1 and 48.7 ppm for compound 2.…”

Section: Analysis Of the Calculated Nmr Parameterssupporting

confidence: 84%

Differentiation between 6- and 7-Membered Rings Based on Theoretical Calculation of NMR Parameters

Klika

2012

ISRN Spectroscopy

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The determination of ring size can vary from simple to complex, but the process in difficult cases can be advantageously augmented by DFT calculation of NMR parameters such as the chemical shifts of (), (), and other nuclei as well as pertinent spin-spin (scalar) coupling constants, for example, those between protons (). Differentiation between 6- and 7-membered ring formation in the case of 3,4-dihydro-2H-3-hydroxymethyl-1,4-benzoxazine and 2,3,4,5-tetrahydro-1,5-benzoxazepine-3-ol was evaluated with a view to not only affecting 6- versus 7-membered ring differentiation generally for cases on hand, but also in the case of literature reports where the assigned structures may be in doubt. Thus, the main focus was on the usually reported NMR parameters of , , and and wherein the analysis was found to be highly successful, particularly for , and thus potentially amenable for broad application.

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Section: Analysis Of the Calculated Nmr Parameterssupporting

confidence: 84%

Differentiation between 6- and 7-Membered Rings Based on Theoretical Calculation of NMR Parameters

Klika

2012

ISRN Spectroscopy

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“…However, in vivo oxygen-17 ( 17 O) NMR has received very little attention compared to other in vivo NMR methodologies, such as 1 H, 13 C and 31 P NMR; even though the 17 O NMR signal was first observed in 1951 [1] and utilized since then for many chemical and biochemical applications (see a recent review by Gerothanassis [2, 3] and the cited references therein).…”

Section: Introductionmentioning

confidence: 99%

In vivo oxygen-17 NMR for imaging brain oxygen metabolism at high field

Zhu

Chen

2011

Progress in Nuclear Magnetic Resonance Spectroscopy

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“…17 O NMR has received little attention in amino acid and peptide research [2, 12, 13, 19, 20]. This neglect is due to the fact that of the three naturally occurring oxygen isotopes, only 17 O possesses a nuclear spin ( I = 5/2).…”

Section: Resultsmentioning

confidence: 99%

On the Hydration State of Amino Acids and Their Derivatives at Different Ionization States: A Comparative Multinuclear NMR and Crystallographic Investigation

Pappas

Tzakos

Gerothanassis

2012

Journal of Amino Acids

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2D, 13C, 14N, and 17O NMR and crystallographic data from the literature were critically evaluated in order to provide a coherent hydration model of amino acids and selected derivatives at different ionization states. 17O shielding variations, longitudinal relaxation times (T 1) of 2D and 13C and line widths (Δν 1/2) of 14N and 17O, may be interpreted with the hypothesis that the cationic form of amino acids is more hydrated by 1 to 3 molecules of water than the zwitterionic form. Similar behaviour was also observed for N-acetylated derivatives of amino acids. An exhaustive search in crystal structure databases demonstrates the importance of six-membered hydrogen-bonded conjugated rings of both oxygens of the α-carboxylate group with a molecule of water in the vicinity. This type of hydrogen bond mode is absent in the case of the carboxylic groups. Moreover, a considerable number of structures was identified with the propensity to form intramolecular hydrogen bond both in the carboxylic acid (NH⋯O=C) and in the carboxylate (NH ⋯ O−) ionization state. In the presence of bound molecules of water this interaction is significantly reduced in the case of the carboxylate group whereas it is statistically negligible in the carboxylic group.

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Oxygen-17 NMR spectroscopy: Basic principles and applications (part II)

Cited by 105 publications

References 1,040 publications

Differentiation between 6- and 7-Membered Rings Based on Theoretical Calculation of NMR Parameters

Differentiation between 6- and 7-Membered Rings Based on Theoretical Calculation of NMR Parameters

In vivo oxygen-17 NMR for imaging brain oxygen metabolism at high field

On the Hydration State of Amino Acids and Their Derivatives at Different Ionization States: A Comparative Multinuclear NMR and Crystallographic Investigation

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