scholarly journals Molecular dynamics of (Z)-1-(2-hydroxy-5-methyl-3-nitrophenyl)ethanone oxime and (E)-2-hydroxy-5-methylacetophenone thiosemicarbazone in solution studied by NMR spectroscopy

2012 ◽  
Vol 10 (1) ◽  
pp. 241-247 ◽  
Author(s):  
Ibrahim Mamedov ◽  
Uwe Eichhoff ◽  
Abel Maharramov ◽  
Musa Bayramov ◽  
Yegana Mamedova
Keyword(s):  
Molecular Dynamics ◽  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Rotational Barrier ◽  
Intramolecular Hydrogen Bonds ◽  
Barrier Energy ◽  
Intramolecular Hydrogen

AbstractThe formation of hydrogen bonds and the molecular dynamics for molecules (Z)-1-(2-hydroxy-5-methyl-3-nitrophenyl)ethanone oxime and (E)-2-hydroxy-5-methylacetophenone thiosemicarbazone, (E)-4-bromoacetophenone thiosemicarbazone have been investigated in solution using NMR. The results confirm the formation of different O-H…O type intramolecular hydrogen bonds in the oxime molecule. The rotational barrier energy and energy of intramolecular hydrogen bonds have been determined.

scholarly journals Resonance-assisted stabilisation of hydrogen bonds probed by NMR spectroscopy and path integral molecular dynamics

2015 ◽  
Vol 51 (73) ◽  
pp. 13986-13989 ◽  
Author(s):  
M. Dračínský ◽  
L. Čechová ◽  
P. Hodgkinson ◽  
E. Procházková ◽  
Z. Janeba
Keyword(s):  
Molecular Dynamics ◽  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Path Integral ◽  
Quantum Effects ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen ◽  
Nuclear Quantum Effects

Nuclear quantum effects are shown to be important for resonance stabilisation of intramolecular hydrogen bonds.

Synthesis of 4-Aryl-3(5)-(2-hydroxyphenyl)pyrazoles by Reaction of Isoflavones and their 4-Thio Analogues with Hydrazine Derivatives

2007 ◽  
Vol 60 (12) ◽  
pp. 905 ◽  
Author(s):  
Albert Lévai ◽  
Artur M. S. Silva ◽  
José A. S. Cavaleiro ◽  
José Elguero ◽  
Ibon Alkorta ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Hydrazine Hydrate ◽  
1H Nmr ◽  
Theoretical Calculations ◽  
Intramolecular Hydrogen Bonds ◽  
Nmr Study ◽  
Intramolecular Hydrogen ◽  
New Compounds

4-Aryl-3(5)-2-(hydroxyphenyl)pyrazoles have been prepared by the reaction of isoflavones and their 4-thio analogues with hydrazine hydrate and phenylhydrazine in hot pyridine. The reaction mechanism for the formation of these pyrazoles is discussed. All the new compounds have been fully characterized by NMR spectroscopy. In [D6]DMSO, a 1H NMR study allows observation of the presence of both pyrazole annular tautomers, due to the presence of intramolecular hydrogen bonds in each tautomer (OH···N and NH···O). Theoretical calculations have been carried out on tautomers and conformers of compounds 20 (3(5)-(2-hydroxy-4-methoxyphenyl)-5(3)-methyl-4-phenylpyrazole) and 21 (3(5)-(2-hydroxy-4-methoxyphenyl)-4-(2-methoxyphenyl)-5(3)-methylpyrazole), including the absolute shieldings (GIAO/B3 LYP/6–311++G**) of 21.

Determination of intramolecular hydrogen bonds in amikacin in water solution by NMR spectroscopy

1995 ◽  
Vol 51 (11) ◽  
pp. 1959-1963 ◽  
Author(s):  
Elena Gaggelli ◽  
Nicola Gaggelli ◽  
Antonella Maccotta ◽  
Gianni Valensin ◽  
Domenico Marini ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Water Solution ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen

Photoswitchable Intramolecular Hydrogen Bonds in 5-Phenylazopyrimidines Revealed By In Situ Irradiation NMR Spectroscopy

2017 ◽  
Vol 24 (2) ◽  
pp. 492-498 ◽  
Author(s):  
Eliška Procházková ◽  
Lucie Čechová ◽  
Jonas Kind ◽  
Zlatko Janeba ◽  
Christina M. Thiele ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen
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