Application of photoelectron spectroscopy to intramolecular hydrogen bonding. 6. The relative importance of electrostatic and covalent contributions to the hydrogen bond of hydrogen-bonded alcohols containing a conjugated olefin as the electron donor

1977 ◽  
Vol 99 (20) ◽  
pp. 6500-6505 ◽  
Author(s):  
R. S. Brown ◽  
Randall W. Marcinko
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Electron Donor ◽  
Photoelectron Spectroscopy ◽  
Intramolecular Hydrogen Bonding ◽  
Relative Importance ◽  
Intramolecular Hydrogen ◽  
Hydrogen Bonded

scholarly journals Conformational analysis and intramolecular interactions in monosubstituted phenylboranes and phenylboronic acids

2013 ◽  
Vol 9 ◽  
pp. 1127-1134 ◽  
Author(s):  
Josué M Silla ◽  
Rodrigo A Cormanich ◽  
Roberto Rittner ◽  
Matheus P Freitas
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Conformational Analysis ◽  
Conformational Equilibrium ◽  
Intramolecular Hydrogen Bonding ◽  
Intramolecular Interactions ◽  
Coupling Constant ◽  
Intramolecular Hydrogen ◽  
Phenylboronic Acids ◽  
Electron Donation

A 1 TS J F,H(O) coupling pathway, dictated by a hydrogen bond, in some 2-fluorobenzoic acids has been observed, while such an interaction does not occur in 2-fluorophenol. Thus, this work reports the conformational analysis of 2-fluorophenylboronic acid (1), in order to evaluate a possible intramolecular OH∙∙∙F hydrogen bond in comparison to an nF→pB interaction, which mimics the quantum nF→σ*OH hydrogen bond that would be expected in 2-fluorophenol. 2-Fluorophenylborane (3), which does not experience hydrogen bonding, was used to verify whether nF→pB interaction governs the conformational equilibrium in 1 due to a predominant OH∙∙∙F hydrogen bond or to other effects. A series of 2-X-phenylboranes (X = Cl, Br, NH2, PH2, OH and SH) were further computationally analyzed to search for electron donors to boron, capable of influencing the conformational equilibrium. Overall, the intramolecular OH∙∙∙F hydrogen bond in 1 is quite stabilizing and dictates the 1 h J F,H(O) coupling constant. Moreover, electron donation to the empty p orbital of boron (for noncoplanar BH2 moiety relative to the phenyl ring) is also significantly stabilizing for the NH2 and PH2 derivatives, but not enough to make the corresponding conformers appreciably populated, because of steric effects and the loss of πCC→pB resonance. Thus, the results found earlier for 2-fluorophenol about the lack of intramolecular hydrogen bonding are now corroborated.

Photoelectron studies on intramolecularly hydrogen-bonded systems. I. The photoelectron spectra of cis- and trans-2-aminocyclopentanol, and cis- and trans-2-(N,N-dimethylamino)cyclopentanol

1976 ◽  
Vol 54 (4) ◽  
pp. 642-646 ◽  
Author(s):  
R. S. Brown
Keyword(s):  
Hydrogen Bonding ◽  
Ionization Energy ◽  
Lone Pair ◽  
Intramolecular Hydrogen Bonding ◽  
Photoelectron Spectra ◽  
Hydrogen Bonded Systems ◽  
Intramolecular Hydrogen ◽  
Cis And Trans ◽  
Infrared Data ◽  
Hydrogen Bonded

The photoelectron spectra of cis- and trans-2-aminocyclopentanol and cis- and trans-2-(N,N,-dimethylamino)cyclopentanol have been recorded and interpreted. The cis isomers exhibit N lone pair ionizations at higher ionization energy, and O lone pair ionizations at lower ionization energy than their trans isomers.The results are most consistent with the existence and observation of intramolecular hydrogen-bonding in the cis isomers. Infrared data on these systems also show that the cis isomers exist in the intramolecularly hydrogen-bonded state.

Application of photoelectron spectroscopy to intramolecularly hydrogen-bonded systems. Part III. The photoelectron spectra of cis and trans 2-substituted cyclopentanols and cis and trans 2-substituted cyclohexanols

1976 ◽  
Vol 54 (12) ◽  
pp. 1929-1937 ◽  
Author(s):  
R. S. Brown
Keyword(s):  
Hydrogen Bonding ◽  
Photoelectron Spectroscopy ◽  
Intramolecular Hydrogen Bonding ◽  
Photoelectron Spectra ◽  
Molecular Orbital Calculations ◽  
Cis And Trans Isomers ◽  
Koopmans Theorem ◽  
Hydrogen Bonded Systems ◽  
Intramolecular Hydrogen ◽  
Cis And Trans

The photoelectron spectra of several well defined molecules exhibiting intramolecular hydrogen bonding has been determined and the analysis of the spectra is in accord with recent molecular orbital calculations of related systems. The experimentally determined enthalpies of the hydrogen bonds in cis-2-aminocyclopentanol and cis- and trans-2-aminocyclohexanol do not correlate in any simple fashion with the shifts in the ionization energies of the nO and nN orbitals compared to a model which precludes hydrogen bonding. The spectral differences attributed to hydrogen bonding in the cis and trans 2-substituted cyclanols cannot be attributed to differences in the through-bond interaction of the n orbitals on either atom since the cis and trans isomers of 1,2-dimethoxycyclopentane and 1,2-dimethoxycyclohexane show virtually identical pe spectra. A discussion of the applicability of Koopmans' theorem and the effect of the hydrogen bond in both the ion and ground states is presented.

Theoretical aspects of the enhancement of metal binding affinity by intramolecular hydrogen bonding and modulating pKavalues

2017 ◽  
Vol 41 (24) ◽  
pp. 15110-15119 ◽  
Author(s):  
Ahmad Motahari ◽  
Alireza Fattahi
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Binding Affinity ◽  
Metal Binding ◽  
Intramolecular Hydrogen Bonding ◽  
Hydrogen Bond Network ◽  
Bond Network ◽  
The Stability ◽  
Intramolecular Hydrogen

The stability balance shows that the hydrogen bond network and modulation of pKavalues can enhance the metal binding affinity.

1,1-Diphenylbutane-1,3-diol: the First Structurally Characterized Example of an Intramolecularly Hydrogen-Bonded Open-Chain 1,3-diol

1996 ◽  
Vol 49 (11) ◽  
pp. 1251
Author(s):  
CF Carvalho ◽  
DP Arnold ◽  
RC Bott ◽  
G Smith
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Orthorhombic Space Group ◽  
Open Chain ◽  
Space Group ◽  
A Cell ◽  
Intramolecular Hydrogen ◽  
Hydroxy Groups ◽  
Hydrogen Bonded

The crystal structure of the asymmetric 1,3-diol 1,1-diphenylbutane-1,3-diol has been determined and refined to a residual R of 0.039 for 795 observed reflections. Crystals are orthorhombic, space group P212121, with four molecules in a cell of dimensions a 9.625(4), b 16.002(3), c 8.834(3) Ǻ. The compound is unique among the known crystallographically characterized open-chain 1,3-diols in having only intramolecular hydrogen bonding involving the hydroxy groups [O-- -O 2.602(5) Ǻ].

scholarly journals Separation of planar rotamers through intramolecular hydrogen bonding in polysubstituted 5-nitrosopyrimidines

2014 ◽  
Vol 50 (94) ◽  
pp. 14892-14895 ◽  
Author(s):  
L. Čechová ◽  
E. Procházková ◽  
I. Císařová ◽  
M. Dračínský ◽  
Z. Janeba
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bond ◽  
Chemical Species ◽  
Intramolecular Hydrogen Bonding ◽  
Nitroso Group ◽  
Group Orientation ◽  
Intramolecular Hydrogen

Unique isolation of pairs of planar rotamers, planamers, as chemical species differing only in nitroso group orientation, separable through the presence of a single intramolecular hydrogen bond, is reported.

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