hydrogen bridge

2020 ◽  
Author(s):  
X.P. Brannmjk
Keyword(s):  
Hydrogen Bridge

Substitutional and solvation effects on conformational equilibria. Effects on the interaction between opposing axial oxygen atoms

1969 ◽  
Vol 47 (23) ◽  
pp. 4441-4446 ◽  
Author(s):  
R. U. Lemieux ◽  
A. A. Pavia
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Hydrogen Bonding ◽  
Magnetic Resonance ◽  
Hydroxyl Groups ◽  
Evidence Based ◽  
Electrostatic Repulsion ◽  
Hydrogen Bridge ◽  
Conformational Equilibria ◽  
Free Hydroxyl ◽  
Oxygen Atoms

Evidence based both on nuclear magnetic resonance and rotation data primarily obtained from methyl 3-deoxy-β-L-erythro-pentopyranoside and a number of its derivatives is interpreted to show that the electrostatic repulsion between the oxygen atoms at the 2 and 4 positions is substantially less when these oxygens are linked to acyl groups than when in the form of either methyl ethers or as hydroxyl groups hydrogen bonded to solvent. Also, experimental evidence is presented which requires the hydrogen bridge between two axially disposed hydroxyl groups to be substantially strengthened by hydrogen bonding of the free hydroxyl by solvent.

scholarly journals Atomic hydrogen bridge fueling NGC 4418 with gas from VV 655

2017 ◽  
Vol 607 ◽  
pp. A43 ◽  
Author(s):  
E. Varenius ◽  
F. Costagliola ◽  
H.-R. Klöckner ◽  
S. Aalto ◽  
H. Spoon ◽  
...  
Keyword(s):  
Atomic Hydrogen ◽  
Hydrogen Bridge

Enolization and Hydrogen Bridge Formation in Cyclopentane β-Tricarbonyl Systems

2010 ◽  
Vol 76 (7-8) ◽  
pp. 455-467 ◽  
Author(s):  
M. Anteunis ◽  
S. Dewaele ◽  
H. De Pooter ◽  
F. Compernolle
Keyword(s):  
Hydrogen Bridge ◽  
Bridge Formation

The Association Band of the Hydrogen Bridge

1952 ◽  
Vol 20 (2) ◽  
pp. 342-342 ◽  
Author(s):  
Mansel Davies ◽  
J. C. Evans
Keyword(s):  
Hydrogen Bridge

A Novel Carbonyldiniobium Complex with Hydrogen Bridge

1981 ◽  
Vol 20 (4) ◽  
pp. 388-389 ◽  
Author(s):  
Wolfgang A. Herrmann ◽  
Helmut Biersack ◽  
Manfred L. Ziegler ◽  
Peter Wülknitz
Keyword(s):  
Hydrogen Bridge

IR-spektroskopische Untersuchungen an NH- und ND-Formazanen

1968 ◽  
Vol 23 (8) ◽  
pp. 1064-1071 ◽  
Author(s):  
W. Otting ◽  
F. A. Neugebauer
Keyword(s):  
Ir Spectra ◽  
Path Length ◽  
Hydrogen Bridge ◽  
Low Field

The solid and solution IR spectra of the yellow formazans (1) show in most cases a strong J'(NH) or ν (ND) band. The ν (NH) absorption of the red formazans (2) is so weak (ε ≈ 1 [liter mole-1 cm-1]), that it is only observed in solutions and with long path length. In the case of C-ethoxycarbonyl-N.N′-diphenylformazan opening of the intramolecular N — H - - - N hydrogen bridge by light gives rise to a new intramolecular N — H - - - O hydrogen bridge. The nuclear N — H resonance of the red formazans is shifted far to low field (14 p. p.m.).

Theoretical study of electron structure and stability of quasiaromatic analogues of azulene

1981 ◽  
Vol 46 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Pavol Zahradník ◽  
Elena Ďurčíková ◽  
Jaroslav Leška
Keyword(s):  
Hydrogen Bond ◽  
Interaction Energy ◽  
Theoretical Study ◽  
Electron System ◽  
Stabilization Energy ◽  
Strong Hydrogen Bond ◽  
Hydrogen Bridge ◽  
Structure And Stability ◽  
Energy Interaction ◽  
The Stability

Semiempirical CNDO/2 method was used in the study of 23 quasiaromatic azulene analogues containing a hydrogen bridge A..H-D, where A and D denote O, NH, or S. The values of the stabilization energy, interaction energy, and changes of Wiberg's indexes suggest that the stability of the studied compounds is caused by a strong hydrogen bond as well as by a strong delocalization of the π-electron system. Derivatives in which A and D are O and NH are especially stable. Derivatives containing an oxo or thio group are preferred in tautomeric equilibriums.

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