Intramolecular hydrogen bond in some ?- and ?-substituted carbalkoxyl derivatives of ?-dicarbonyl compounds

1976 ◽  
Vol 16 (6) ◽  
pp. 984-985
Author(s):  
L. N. Kurkovskaya ◽  
N. N. Shapet'ko ◽  
Yu. S. Andreichikov ◽  
V. L. Gein ◽  
G. D. Plakhina ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Intramolecular Hydrogen Bond ◽  
Dicarbonyl Compounds ◽  
Intramolecular Hydrogen ◽  
Derivatives Of

Hydrogen bonding, configuration and conformation of substituted α-oxo oximes and hydrazones

1979 ◽  
Vol 44 (8) ◽  
pp. 2494-2506 ◽  
Author(s):  
Otto Exner ◽  
Jorga Smolíková ◽  
Václav Jehlička ◽  
Ahmad S. Shawali
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Carbonyl Group ◽  
Intramolecular Hydrogen Bond ◽  
Benzene Solution ◽  
Dipole Moments ◽  
H Nmr ◽  
Intramolecular Hydrogen ◽  
Derivatives Of ◽  
Configuration And Conformation

Substituted 2-bromo-1-phenylglyoxal 2-phenylhydrazones IIIa-f exist in tetrachloromethane or benzene solutions prevailingly in E-configuration and in conformation A with an intramolecular hydrogen bond. The latter was evidenced by the N-H valence frequency at 3 290 cm-1 and by 1H NMR shifts with reference to derivatives without a carbonyl group - α-chlorobenzaldehyde phenylhydrazones V. From dipole moments of IIIa-d, measured in benzene solution, the contribution of the hydrogen bond (μH) was evaluated to 17 . 10-30 C m. This quantity is twice larger than in any other reported compound but the direction of the vector is as usual: approximately from H to N. In structurally similar derivatives of hydroxylamine, substituted 2-phenylglyoxylhydroximoyl chlorides IVa-d, no intramolecular hydrogen bond was detected; the dipole moments found were interpreted in terms of the Z-configuration and the prevailing conformation G.

scholarly journals Intramolecular hydrogen bond directed distribution of conformational populations in the derivatives of N′-benzylidenebenzohydrazide

2019 ◽  
Vol 43 (33) ◽  
pp. 13134-13142 ◽  
Author(s):  
Neeru Arya ◽  
Sandeep Kumar Mishra ◽  
N. Suryaprakash
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Intramolecular Hydrogen Bond ◽  
Intramolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen ◽  
Derivatives Of

The extensive NMR investigations reveal the presence of E-isomers in the derivative of N′-benzylidenebenzohydrazide. The different conformer populations are controlled by the strength of intramolecular hydrogen bonds.

The intramolecular hydrogen bond as a unit of molecular electronics: Molecular switching controlled by overcrowded intramolecular three-centered hydrogen bond

2018 ◽  
Vol 17 (04) ◽  
pp. 1850023 ◽  
Author(s):  
Andrei V. Afonin ◽  
Alexander V. Vashchenko
Keyword(s):  
Hydrogen Bond ◽  
Molecular Electronics ◽  
Intramolecular Hydrogen Bond ◽  
Intramolecular Hydrogen Bonding ◽  
Equilibrium Geometry ◽  
Stable States ◽  
Molecular Switching ◽  
External Impact ◽  
Intramolecular Hydrogen ◽  
Derivatives Of

The equilibrium geometry of the 2,5-bis-[2-(pyridin-2-yl)-vinyl]-1[Formula: see text]-pyrrole calculated at the MP2/6-311[Formula: see text]G([Formula: see text],[Formula: see text]) level of theory evidences the breaking of one of the components in the three-centered intramolecular hydrogen bond due to the steric strain. For this reason, the three-centered intramolecular hydrogen bonding turns out to be asymmetric interaction involving the major and minor components. However, the reversible switching between these components under an external impact is also possible. Two different stable states with unequal geometric and electronic structure are observed in the derivatives of the 2,5-bis-[2-(pyridin-2-yl)-vinyl]-1[Formula: see text]-pyrrole. These molecules represent novel molecular switches operating due to the pendulum-like transition between the nonequivalent two-centered components of the overcrowded three-centered intramolecular hydrogen bond. Implantation of hydrogen bond as a unit of the molecular scale device enhances potential of molecular electronics and could serve as a step towards the construction of artificial biological ensembles.

scholarly journals Electronic structure of planar-quasicycled organic molecules with intramolecular hydrogen bond

2007 ◽  
Vol 72 (3) ◽  
pp. 265-273
Author(s):  
Alexei Pankratov ◽  
Alexei Shalabay
Keyword(s):  
Hydrogen Bond ◽  
Electronic Structure ◽  
Hydrogen Atom ◽  
Electron Density ◽  
Intramolecular Hydrogen Bond ◽  
Organic Molecules ◽  
Local Electron ◽  
Intramolecular Hydrogen ◽  
Derivatives Of ◽  
Density Transfer

By means of the HF/6-311G(d,p) method, the electronic structure of the series of organic molecules, among which are malonaldehyde, acetylacetone, thiomalonaldehyde,?the derivatives of aniline 2-XC6H4NH2, phenol 2-XC6H4OH, benzenethiol 2-XC6H4SH (X = CHO, COOH, COO-, NO, NO2, OH, OCH3, SH, SCH3, F, Cl, Br), 8-hydroxyquinoline, 8-mercaptoquinoline, tropolone, has been studied. The intramolecular hydrogen bond (IHB) has been established to lead to a local electron redistribution in quasicycle, and primarily to the electron density transfer between the direct IHB participants - from the hydrogen atom toward the proton-aceptor atom. On forming the IHB of the S-H???O type, the electron density in general decreases on the sulphohydryl hydrogen atom and increases on the sulphur atom.

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