Vapour phase infrared studies of alcohols - I. Intramolecular interactions and self-association

1973 ◽  
Vol 335 (1600) ◽  
pp. 97-111 ◽  
Keyword(s):  
Hydrogen Bonding ◽  
Infrared Spectra ◽  
Path Length ◽  
Intramolecular Hydrogen Bonding ◽  
Vapour Phase ◽  
Intramolecular Interactions ◽  
Argon Matrix ◽  
Infrared Studies ◽  
Self Association ◽  
Intramolecular Hydrogen

Infrared spectra are reported of methanol, ethanol, propan-2-ol, 2-methylpropan-2-ol, 2, 2, 2-trifluoroethanol, 2, 2, 3, 3-tetrafluoropropan-1-ol and 1, 1, 1, 3, 3, 3-hexafluoropropan-2-ol in the vapour phase in a 1 m path-length cell at pressures up to the s. v. p. of the alcohol. Also reported are 40 m path-length vapour and argon matrix spectra of trifluoroethanol. Dimer absorptions are identified for all the alkanols and for trifluoroethanol, and some estimates of ∆ H provided. Trifluoroethanol exhibits a striking series of sum-and-difference bands of the OH stretch with other fundamentals, 14 summation modes being observed extending in frequency to over 5000 cm -1 and involving most of the fundamentals below 1500 cm -1 . Other fluoroalcohols with fluorines substituted on β carbon atoms exhibit similar sum-and-difference modes. The alkanols exhibit only one such pair of bands due to the OH stretch plus or minus the OH torsion, and this provides a convenient method of measuring the torsional frequencies. The different behaviour of the fluoroalcohols is attributed to intramolecular hydrogen bonding.

Infrared studies on rotational isomerism. III. 2-Chloro- and 2-bromo-ethanol

1969 ◽  
Vol 47 (6) ◽  
pp. 901-910 ◽  
Author(s):  
Paul Buckley ◽  
Paul A. Giguère ◽  
Michel Schneider
Keyword(s):  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonding ◽  
Rotational Isomerism ◽  
Apparent Discrepancy ◽  
Trans Isomers ◽  
Kcal Mole ◽  
Infrared Studies ◽  
Isotopic Molecule ◽  
Intramolecular Hydrogen ◽  
Unambiguous Assignment

The relative intensities of the C—X stretching bands of the gauche and trans isomers in the vapor were measured as a function of temperature up to 165 °C for 2-chloroethanol, and up to 130 °C for 2-bromoethanol. From these the enthalpy differences between the two isomers were found to be 1.20 and 1.45 ± 0.1 kcal mole−1 respectively for the two halogenated ethanols. Similar measurements on the O—H stretching bands gave values higher than the above by 0.45 kcal mole−1 for both compounds. This apparent discrepancy is interpreted as due to a second gauche isomer, the OH group of which is not engaged in intramolecular hydrogen bonding, and which is less stable than the trans isomer.A study of the isotopic molecule ClCH2—CH2OD has led to unambiguous assignment of the OH bending and torsional frequencies. The spectra of the solid show that 2-chloroethanol can exist in two different crystalline phases: a stable one consisting of gauche molecules only, and a metastable one containing both isomers.

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.

Infrared Study of Some Oxalamidines

1965 ◽  
Vol 19 (2) ◽  
pp. 48-51 ◽  
Author(s):  
Vasile P. Macovei ◽  
D. W. Robinson
Keyword(s):  
Hydrogen Bonding ◽  
Infrared Spectra ◽  
Intramolecular Hydrogen Bonding ◽  
Solution Concentration ◽  
Infrared Study ◽  
Vibrational Bands ◽  
Intramolecular Hydrogen

Infrared spectra of various aromatic-substituted oxalamidines have been obtained. The behavior of the vibrational bands originating in the amidine groupings as a function of solution concentration is interpreted as indicating the presence of persistent intramolecular hydrogen bonding.

THE STUDY OF HYDROGEN BONDING AND RELATED PHENOMENA BY SPECTROSCOPIC METHODS: PART VII. INTRAMOLECULAR HYDROGEN BONDING AND STERIC INTERACTIONS IN o-NITROBENZALDEHYDE AND RELATED COMPOUNDS

1962 ◽  
Vol 40 (10) ◽  
pp. 1891-1898 ◽  
Author(s):  
W. F. Forbes
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Infrared Spectra ◽  
Intramolecular Hydrogen Bonding ◽  
Spectroscopic Methods ◽  
Steric Interactions ◽  
Spectral Changes ◽  
Suitable Reference ◽  
Intramolecular Hydrogen ◽  
Related Compounds

Certain unusual features in the infrared spectra of o-nitrobenzaldehyde have been interpreted either in terms of an intramolecular hydrogen bond or in terms of steric interactions. As an extension of these studies we have investigated the ultraviolet, infrared, and n.m.r. spectra of o-nitrobenzaldehyde and of suitable reference compounds and have re-examined the available other evidence. It is concluded that the observed spectral changes can best be explained in terms of steric interactions rather than in terms of intramolecular hydrogen bonding.

scholarly journals Infrared Spectra and Intramolecular Hydrogen Bonding of 4-(Haloacetylamino)diphenylamines

1991 ◽  
Vol 64 (9) ◽  
pp. 2863-2864 ◽  
Author(s):  
Hiroko Suezawa ◽  
Minoru Hirota ◽  
Yoshiki Hamada ◽  
Isao Takeuchi ◽  
Takae Kawabe
Keyword(s):  
Hydrogen Bonding ◽  
Infrared Spectra ◽  
Intramolecular Hydrogen Bonding ◽  
Intramolecular Hydrogen

Intramolecular hydrogen bonding stabilizes the nuclearity of complexes. A comparative study based on the H-carborane and Me-carborane framework

2015 ◽  
Vol 44 (22) ◽  
pp. 10399-10409 ◽  
Author(s):  
Mònica Fontanet ◽  
Montserrat Rodríguez ◽  
Xavier Fontrodona ◽  
Isabel Romero ◽  
Clara Viñas ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Comparative Study ◽  
Intramolecular Hydrogen Bonding ◽  
Intramolecular Interactions ◽  
Intramolecular Hydrogen

The H– on the adjacent carbon of the carboranylcarboxylate ligand is responsible for intramolecular interactions that stabilize the nuclearity of Cu(ii) complexes.

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