𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Isotope effects on proton chemical shifts and coupling constants in the ammonium ions 15, 14 NH4-nDn+

✍ Scribed by Jeremy K.M. Sanders; Brian K. Hunter; Cynthia J. Jameson; Giovanni Romeo

Publisher
Elsevier Science
Year
1988
Tongue
English
Weight
490 KB
Volume
143
Category
Article
ISSN
0009-2614

No coin nor oath required. For personal study only.

✦ Synopsis

The proton NMR spectra of '*N-and '5N-ammonium ions have been recorded in H20/D20 mixtures under (acidic) conditions of slow proton exchange. Successive deuterium substitutions lead to unusual downfield shifts of about 20 ppb/D at the residual protons, but the effect is not additive; the increment increases by about 10% per deuterium. r&u is reduced by a secondary deuterium isotope effect and "N induces an upfield 'H shift of 1.5 ppb. The magnitudes of the isotope shifts are consistent with the theoretical shielding derivatives. We believe that the unusual sign and the large deviations from additivity of the deuteration shifts are due to intermolecular effects.

📜 SIMILAR VOLUMES

Isotope effects on the 13C chemical shif
Isotope effects on the 13C chemical shift and carbon–proton coupling constant in dichloromethane
✍ N. M. Sergeyev; N. D. Sergeyeva; W. T. Raynes 📂 Article 📅 1994 🏛 John Wiley and Sons 🌐 English ⚖ 489 KB

## Abstract Carbon–proton and carbon–deuteron coupling constants were measured in the isotopomers CH~2~Cl~2~, CHDCl~2~ and CD~2~Cl~2~. The primary and secondary isotope effects on the carbon–proton coupling are −0.60 (±0.05) and −0.25 (±0.01) Hz, respectively. The deuterium‐induced ^13^C isotope sh

13C13C spin–spin coupling constants and
13C13C spin–spin coupling constants and 13C isotope effects on 13C chemical shifts in some 4-membered rings
✍ Jukka Jokisaari 📂 Article 📅 1978 🏛 John Wiley and Sons 🌐 English ⚖ 272 KB

## Abstract The ^13^C^13^C spin–spin coupling constants in natural abundance oxetane, thietane, cyclobutanone, bromo‐and chlorocyclobutane have been measured. Furthermore, the ^13^C isotope‐induced changes in the chemical shifts of the different ^13^C nuclei in the molecules mentioned above are re

Sign and magnitude of the phosphorus–pho
Sign and magnitude of the phosphorus–phosphorus coupling constant in the [cyclopentadienyltris(trimethylphosphine)iron]+ cation of [(η5-C5H5)(Me3P)3Fe]BF4and the 13C/12C isotope effect on the 31P chemical shift
✍ Wolfgang Buchner; Wolfgang Ries; Wolfgang Malisch 📂 Article 📅 1990 🏛 John Wiley and Sons 🌐 English ⚖ 184 KB

## Abstract The ^13^C NMR methyl group multiplet of the [cyclopentadienyltris(trimethylphosphine)iron]^+^ cation was simulated to obtain the sign and magnitude of the phosphorus‐phosphorus coupling constant and the ^13^C/^12^C isotope effect on the ^31^P chemical shift.