X-ray, Fourier-transform infrared,1H and13C nuclear magnetic resonance, and PM3 studies of (N—H⋯N)+and (O—H⋯O)–intramolecular hydrogen bonds in a complex of 1,8-bis(dimethylamino)naphthalene with maleic acid

1993 ◽  
Vol 89 (12) ◽  
pp. 2085-2094 ◽  
Author(s):  
Elżbieta Bartoszak ◽  
Zofia Dega-Szafran ◽  
Monika Grundwald-Wyspiańska ◽  
Mariusz Jaskólski ◽  
Miroslaw Szafran
2018 ◽  
Vol 5 (6) ◽  
pp. 180088 ◽  
Author(s):  
M. Petrova ◽  
R. Muhamadejev ◽  
B. Vigante ◽  
G. Duburs ◽  
Edvards Liepinsh

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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