Proton, deuterium, and tritium nuclear magnetic resonance of intramolecular hydrogen bonds. Isotope effects and the shape of the potential energy function

1978 ◽  
Vol 100 (26) ◽  
pp. 8264-8266 ◽  
Author(s):  
Lawrence J. Altman ◽  
Pilip Laungani ◽  
Gudmundur Gunnarsson ◽  
Hakan Wennerstrom ◽  
Sture Forsen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Hydrogen Bonds ◽  
Potential Energy ◽  
Energy Function ◽  
Isotope Effects ◽  
Potential Energy Function ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen ◽  
Nuclear Magnetic

scholarly journals Intramolecular hydrogen bonds in 1,4-dihydropyridine derivatives

2018 ◽  
Vol 5 (6) ◽  
pp. 180088 ◽  
Author(s):  
M. Petrova ◽  
R. Muhamadejev ◽  
B. Vigante ◽  
G. Duburs ◽  
Edvards Liepinsh
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Hydrogen Bonds ◽  
Quantum Chemical ◽  
Variable Temperature ◽  
Chemical Calculation ◽  
Hydrogen Bond Formation ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen ◽  
Nuclear Magnetic

1,4-Dihydropyridine (1,4-DHP) derivatives have been synthesized and characterized by 1 H, 13 C, 15 N nuclear magnetic resonance (NMR) spectroscopy, secondary proton/deuterium 13 C isotope shifts, variable temperature 1 H NMR experiments and quantum-chemical calculation. The intramolecular hydrogen bonds NH⋯O=C and CH⋯O=C in these compounds were established by NMR and quantum-chemical studies The downfield shift of the NH proton , accompanied by the upfield shift of the 15 N nuclear magnetic resonance signals, the shift to the higher wavenumbers of the NH stretching vibration in the infrared spectra and the increase of the 1 J( 15 N, 1 H) values may indicate the shortening of the N–H bond length upon intramolecular NH⋯O=C hydrogen bond formation.

The influence of charge on nuclear magnetic resonance isotope effects

1987 ◽  
Vol 65 (12) ◽  
pp. 2707-2712 ◽  
Author(s):  
Roderick E. Wasylishen ◽  
Neil Burford
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Isotope Effects ◽  
Heavy Atom ◽  
Coupling Constants ◽  
Molecular Orbital Calculations ◽  
Isoelectronic Series ◽  
Deuterium Isotope Effects ◽  
Charged Ions ◽  
Nuclear Magnetic

Deuterium isotope effects on the 31P shielding constants and spin–spin coupling constants in the isoelectronic series, PH2−, PH3, PH4+, are examined. Also, deuterium isotope effects on the nuclear magnetic resonance parameters of SnH3− are examined and compared with our earlier results on SnH4 and SnH3+. The experimental results are analyzed using the models of Jameson and Osten. In each isoelectronic series it is found that the isotope effects on the heavy atom chemical shifts are largest for the negatively charged ions and essentially zero for the positively charged ions, as predicted by recent molecular orbital calculations. The primary isotope effects on J(A,H) are positive for all species containing lone-pair electrons, otherwise Δp1J(A,H) is negative. The primary and secondary isotope effects on J(Sn,H) in the SnH3− ion are the largest reported to date.

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