Deuterium isotope effects on <sup>13</sup>C chemical shifts of negatively charged NH…N systems

Pietrzak, Mariusz; Grech, E.; Nowicka‐Scheibe, J.; Hansen, Poul Erik

doi:10.1002/mrc.4000

Cited by 4 publications

(4 citation statements)

References 29 publications

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“…The effect of the counter ion has been studied. In Figure 22, the counter ion is a proton-like sponge [54]. The effects in the proton sponge are similar to previous examples.…”

Section: Tautomerismsupporting

confidence: 78%

Isotope Effects on Chemical Shifts in the Study of Hydrogen Bonds in Small Molecules

Hansen

2022

Molecules

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This review is giving a short introduction to the techniques used to investigate isotope effects on NMR chemical shifts. The review is discussing how isotope effects on chemical shifts can be used to elucidate the importance of either intra- or intermolecular hydrogen bonding in ionic liquids, of ammonium ions in a confined space, how isotope effects can help define dimers, trimers, etc., how isotope effects can lead to structural parameters such as distances and give information about ion pairing. Tautomerism is by advantage investigated by isotope effects on chemical shifts both in symmetric and asymmetric systems. The relationship between hydrogen bond energies and two-bond deuterium isotope effects on chemical shifts is described. Finally, theoretical calculations to obtain isotope effects on chemical shifts are looked into.

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“…The effect of the counter ion has been studied. In Figure 22, the counter ion is a proton-like sponge [54]. The effects in the proton sponge are similar to previous examples.…”

Section: Tautomerismsupporting

confidence: 78%

Isotope Effects on Chemical Shifts in the Study of Hydrogen Bonds in Small Molecules

Hansen

2022

Molecules

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“…These systems are typically tautomeric and show strong intramolecular hydrogen bonds. [53], (B) and (C) from [54]. (D) from [55].…”

Section: Hn Chemical Shiftsmentioning

confidence: 99%

“…Even when the hydrogen bond is part of a seven membered ring, they are clearly forming strong hydrogen bonds. As acceptors thiones are better than pyridines and other nitrogen containing rings, imines are better (B,C) from [54]. (D) from [55].…”

Section: Hn Chemical Shiftsmentioning

confidence: 99%

A Spectroscopic Overview of Intramolecular Hydrogen Bonds of NH…O,S,N Type

Hansen

2021

Molecules

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Intramolecular NH…O,S,N interactions in non-tautomeric systems are reviewed in a broad range of compounds covering a variety of NH donors and hydrogen bond acceptors. 1H chemical shifts of NH donors are good tools to study intramolecular hydrogen bonding. However in some cases they have to be corrected for ring current effects. Deuterium isotope effects on 13C and 15N chemical shifts and primary isotope effects are usually used to judge the strength of hydrogen bonds. Primary isotope effects are investigated in a new range of magnitudes. Isotope ratios of NH stretching frequencies, νNH/ND, are revisited. Hydrogen bond energies are reviewed and two-bond deuterium isotope effects on 13C chemical shifts are investigated as a possible means of estimating hydrogen bond energies.

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“…A DMANH + cation is the counter ion in this case. The 1 H chemical shifts of the NH protons are 15.6 and 15.1 ppm for 18 and 19 [ 116 ].…”

Section: Intramolecular Hydrogen Bonds Without a Double Bond Linkementioning

confidence: 99%

NMR and IR Investigations of Strong Intramolecular Hydrogen Bonds

2017

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For the purpose of this review, strong hydrogen bonds have been defined on the basis of experimental data, such as OH stretching wavenumbers, νOH, and OH chemical shifts, δOH (in the latter case, after correction for ring current effects). Limits for O–H···Y systems are taken as 2800 > νOH > 1800 cm−1, and 19 ppm > δOH > 15 ppm. Recent results as well as an account of theoretical advances are presented for a series of important classes of compounds such as β-diketone enols, β-thioxoketone enols, Mannich bases, proton sponges, quinoline N-oxides and diacid anions. The O···O distance has long been used as a parameter for hydrogen bond strength in O–H···O systems. On a broad scale, a correlation between OH stretching wavenumbers and O···O distances is observed, as demonstrated experimentally as well as theoretically, but for substituted β-diketone enols this correlation is relatively weak.

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Deuterium isotope effects on ¹³C chemical shifts of negatively charged NH…N systems

Cited by 4 publications

References 29 publications

Isotope Effects on Chemical Shifts in the Study of Hydrogen Bonds in Small Molecules

Isotope Effects on Chemical Shifts in the Study of Hydrogen Bonds in Small Molecules

A Spectroscopic Overview of Intramolecular Hydrogen Bonds of NH…O,S,N Type

NMR and IR Investigations of Strong Intramolecular Hydrogen Bonds

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Deuterium isotope effects on 13C chemical shifts of negatively charged NH…N systems

Cited by 4 publications

References 29 publications

Isotope Effects on Chemical Shifts in the Study of Hydrogen Bonds in Small Molecules

Isotope Effects on Chemical Shifts in the Study of Hydrogen Bonds in Small Molecules

A Spectroscopic Overview of Intramolecular Hydrogen Bonds of NH…O,S,N Type

NMR and IR Investigations of Strong Intramolecular Hydrogen Bonds

Contact Info

Product

Resources

About

Deuterium isotope effects on ¹³C chemical shifts of negatively charged NH…N systems