scholarly journals Conformational equilibrium in supramolecular chemistry: Dibutyltriuret case

2015 ◽  
Vol 11 ◽  
pp. 2105-2116 ◽  
Author(s):  
Karina Mroczyńska ◽  
Małgorzata Kaczorowska ◽  
Erkki Kolehmainen ◽  
Ireneusz Grubecki ◽  
Marek Pietrzak ◽  
...  

The association of substituted benzoates and naphthyridine dianions was used to study the complexation of dibutyltriuret. The title molecule is the simplest molecule able to form two intramolecular hydrogen bonds. The naphthyridine salt was used to break two intramolecular hydrogen bonds at a time while with the use of substituted benzoates the systematic approach to study association was achieved. Both, titrations and variable temperature measurements shed the light on the importance of conformational equilibrium and its influence on association in solution. Moreover, the associates were observed by mass spectrometry. The DFT-based computations for complexes and single bond rotational barriers supports experimental data and helps understanding the properties of multiply hydrogen bonded complexes.

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.


Author(s):  
Jacek Waluk ◽  
Arkadiusz Listkowski ◽  
Natalia Masiera ◽  
Michał Kijak ◽  
Roman Luboradzki ◽  
...  

1974 ◽  
Vol 20 (3) ◽  
pp. 414-415
Author(s):  
Ya. A. Shuster ◽  
V. A. Granzhan ◽  
P. M. Zaitsev

1991 ◽  
Vol 56 (4) ◽  
pp. 880-885 ◽  
Author(s):  
Oľga Hritzová ◽  
Dušan Koščík

Intramolecular hydrogen bonds of the N-H···O=C type have been detected in the derivatives of N-substituted N’-benzoyl- and N’-(2-chlorobenzoyl)thiourea on the basis of IR spectral studies. The title compounds can exist in two tautomeric forms.


1985 ◽  
Vol 25 (5) ◽  
pp. 808-810
Author(s):  
L. N. Kurkovskaya ◽  
Yu. M. Chunaev ◽  
N. M. Przhiyalgovskaya

2011 ◽  
Vol 89 (8) ◽  
pp. 971-977
Author(s):  
Danielle M. Chisholm ◽  
Robert McDonald ◽  
J. Scott McIndoe

Methylation of aromatic amino groups is usually straightforward, but the formation of two intramolecular hydrogen bonds in 3,3′-N,N′-bis(amino)-2,2′-bipyridine and (or) the potential for ring methylation prevents the clean tetramethylation of this molecule. Numerous attempts to make 3,3′-N,N′-bis(dimethylamino)-2,2′-bipyridine produced only complex mixtures of variously methylated products, and the only isolated molecule was 3,3′-N,N′-bis(methylamino)-2,2′-bipyridine, for which an X-ray crystal structure was obtained.


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