Quantum chemical calculations and nuclear magnetic resonance measurements on benzyl-type carbanions. Part 2. Influence of countercations and interacting unsaturated systems

1986 ◽  
pp. 707 ◽  
Author(s):  
Guido Vanermen ◽  
Suzanne Toppet ◽  
Marcel Van Beylen ◽  
Paul Geerlings
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
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.

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