PROTONATED γ-PYRONES

1963 ◽  
Vol 41 (2) ◽  
pp. 505-514 ◽  
Author(s):  
Denys Cook
Keyword(s):  
Hydrogen Bond ◽  
Solid State ◽  
Hydrogen Atom ◽  
Oxygen Atom ◽  
Plane Deformation ◽  
Carbonyl Oxygen ◽  
Out Of Plane ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
Deformation Modes

The vibrational spectra of several salts of 4-pyrone and 2,6-dimethyl-4-pyrone have been measured in the solid state. Deuterium replacement has been used to identify motions of the hydrogen atom which is located on the carbonyl oxygen atom and forms a hydrogen bond with the anion.Bands due to OH stretching vibrations have been observed from 2086 cm−1 in the HCl salt to 3310 cm−1 in the hexachloroantimonate of 2,6-dimethyl-4-pyrone. In-plane hydrogen-deformation modes of the OH group have been found near 1300 cm−1 with a much smaller range in the different salts than the stretching vibration. For the 4-pyrone salts the OH stretching vibrations were at similar frequencies, and the in-plane hydrogen-deformation frequencies were close to 1340 cm−1. Bands due to the out-of-plane deformation were not observed.Aqueous solutions of 2,6-dimethyl-4-pyrone hydrochloride at various concentrations showed the presence of both protonated and neutral molecules.

The infrared spectra of theobromine salts

1967 ◽  
Vol 45 (23) ◽  
pp. 2899-2902 ◽  
Author(s):  
Denys Cook ◽  
Zephyr R. Regnier
Keyword(s):  
Hydrogen Bond ◽  
Nitrogen Atom ◽  
Infrared Spectra ◽  
Imidazole Ring ◽  
Free Base ◽  
Absorption Bands ◽  
Out Of Plane ◽  
Stretching Vibrations ◽  
Deformation Modes ◽  
Infrared Absorption Bands

From the infrared spectra of theobromine salts it is concluded that the salts are probably arranged in hydrogen-bonded centrosymmetric pairs involving [Formula: see text] interactions. [Formula: see text] anion− hydrogen bonds are formed by protonation of the free nitrogen atom (N9) in the imidazole ring. Infrared absorption bands arising from the former hydrogen bond constantly appear near 3 000 cm−1, whereas those from the latter shift from 2 580 to 3 300 cm−1, depending on the anion. In-plane NH and N+H deformation modes give bands near 1 485 and 1 160 cm−1, respectively. Out-of-plane NH modes have been located, but precise assignments are not possible.The assignments for some other bands which show deuteration shifts are detailed, and the carbonyl stretching vibrations which increase in frequency on protonation of the free base are identified.

Infrared and Raman polarized spectra of ammonium hydrogen bis(trichloroacetate) single crystal

1985 ◽  
Vol 63 (12) ◽  
pp. 3597-3604 ◽  
Author(s):  
Veneta Videnova-Adrabinska ◽  
Jan Baran ◽  
Henryk Ratajczak ◽  
William J. Orville-Thomas
Keyword(s):  
Hydrogen Bond ◽  
Single Crystal ◽  
Plane Deformation ◽  
Potential Energy Function ◽  
Strong Hydrogen Bond ◽  
Site Symmetry ◽  
Infrared And Raman Spectra ◽  
Out Of Plane ◽  
Ammonium Hydrogen ◽  
Stretching Vibration

The polarized infrared and Raman spectra of ammonium hydrogen bis(trichloroacetate) single crystal have been investigated in the 4000–350 cm−1 and 4000–10 cm−1 range, respectively. The infrared spectra have been measured at room and low temperatures. An assignment of the bands in terms of approximate type of motion is given. The asymmetric stretching vibration, vaOHO, of the strong hydrogen bond gives rise to a very broad infrared absorption, with a maximum around 800 ± 50 cm−1, which is polarized strictly along a tetragonal Z(c) direction of this crystal. For this vibration a correlation field (Davydov or factor group) splitting is not observed. The out-of-plane deformation vibration, γOHO, obeys selection rules for the C2 site symmetry group. This result and also an interpretation of the vC=O vibration strongly suggest that a potential energy function of the strong hydrogen bond has a single symmetric minimum.

Single Crystal Formation by Solid-State Reaction Between p-Benzoquinone and 2,4,5-Trichlorophenol

2002 ◽  
Vol 55 (4) ◽  
pp. 271 ◽  
Author(s):  
N. B. Singh ◽  
A. Pathak ◽  
R. Fröhlich
Keyword(s):  
Hydrogen Bond ◽  
Solid State ◽  
Single Crystal ◽  
Single Crystals ◽  
Solid State Reaction ◽  
Carbonyl Oxygen ◽  
Crystal Formation ◽  
X Ray Diffraction ◽  
X Ray

Vapours of p-benzoquinone (BQ) have been found to react with solid 2,4,5-trichlorophenol (TCP). The reaction product (BQ-TCP) separated in the form of monoclinic single crystals, the structure of which was determined by X-ray diffraction to reveal that the two molecules are linked by a single hydrogen bond between the carbonyl oxygen of BQ and the phenolic hydrogen of TCP.

Effect of functional group conformation on the infrared spectra of some gem difunctional phenylethylene derivatives

1969 ◽  
Vol 47 (17) ◽  
pp. 3147-3152 ◽  
Author(s):  
D. J. Currie ◽  
C. E. Lough ◽  
F. K. McClusky ◽  
H. L. Holmes
Keyword(s):  
Absorption Band ◽  
Functional Groups ◽  
Infrared Spectra ◽  
Functional Group ◽  
Plane Deformation ◽  
Carbonyl Groups ◽  
Deformation Bands ◽  
Or Groups ◽  
Out Of Plane ◽  
Stretching Vibrations

Except for the benzalmalononitriles, two functional group stretching vibrations occur in the infrared (i.r.) spectra of the β,β-difunctional-styrenes with similar functional groups. For geometrically homogeneous compounds with dissimilar functional groups only one absorption band occurs for each functional group. The two bands for similar functional groups have been ascribed to S-cis- and S-trans-conformations of the carbonyl groups with respect to the ethylene and variation in the frequencies of each of these oriented carbonyls to rotation of the functional group or groups out of the plane of the ethylene by steric factors.Frequencies for ethylenic C—H out of plane deformation bands for β-monofunctional styrenes accorded with those already assigned to this vibration. A similar assignment could not be made for the difunctional analogues.

scholarly journals Structure Elucidation of N-aryl-2-chloro-3-oxobutanamides with respect to intra- and intermolecular hydrogen bonding

2002 ◽  
Vol 2002 (1) ◽  
pp. 13-14 ◽  
Author(s):  
Petra Frohberg ◽  
Guntram Drutkowski ◽  
Christoph Wagner ◽  
Olaf Lichtenberger
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Solid State ◽  
Structure Elucidation ◽  
Intermolecular Hydrogen Bond ◽  
Carbonyl Oxygen ◽  
Intermolecular Hydrogen Bonding ◽  
Intramolecular Association

In general, N-aryl-2-chloro-3-oxobutanamides form in solid state an intermolecular hydrogen bond between the anilide hydrogen and the anilide carbonyl oxygen of a neighbouring molecule, which is disrupted in solution. An intramolecular association could not be detected.

scholarly journals Aggregation of Molecules in Liquid Ethylene Glycol and Its Manifestation in Experimental Raman Spectra and Non-Empirical Calculations

2020 ◽  
Vol 65 (4) ◽  
pp. 298
Author(s):  
H. Hushvaktov ◽  
A. Jumabaev ◽  
G. Murodov ◽  
A. Absanov ◽  
G. Sharifov
Keyword(s):  
Hydrogen Bond ◽  
Raman Spectroscopy ◽  
Hydrogen Atom ◽  
Hydrogen Bonds ◽  
Oxygen Atom ◽  
Ethylene Glycol ◽  
Bond Length ◽  
Raman Spectra ◽  
Intermolecular Hydrogen Bond ◽  
The Other

Intra- and intermolecular interactions in liquid ethylene glycol have been studied using the Raman spectroscopy method and non-empirical calculations. The results of non-empirical calculations show that an intermolecular hydrogen bond is formed between the hydrogen atom of the OH group in one ethylene glycol molecule and the oxygen atom in the other molecule. The formation of this bond gives rise to a substantial redistribution of charges between those atoms, which, nevertheless, insignificantly changes the bond length. In the corresponding Raman spectra, the presence of hydrogen bonds between the ethylene glycol molecules manifests itself as the band asymmetry and splitting.

Anharmonicity, solvent effects, and hydrogen bonding: NH stretching vibrations

1970 ◽  
Vol 48 (14) ◽  
pp. 2197-2203 ◽  
Author(s):  
A. Foldes ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Solvent Effects ◽  
Bond Formation ◽  
Hydrogen Bond Formation ◽  
Stretching Vibration ◽  
Solvent Shifts ◽  
Stretching Vibrations ◽  
Secondary Amides ◽  
Influence Of Solvent

The influence of solvent effects and hydrogen bond formation on the anharmonicity of the NH stretching vibration of simple secondary amides, lactams, anilides, indole, pyrrole, and imidazole have been studied; and the frequencies of the first and second overtones, their half widths and solvent shifts measured. The validity of Buckingham's theory is established in the case of inert solvents; whereas the second order perturbation treatments are shown to be inapplicable to the case of hydrogen bonding solvents. All NH stretching modes seem to exhibit the same anharmonic behavior which is very different from that of OH vibrations.

The effects of solvents on the stretching vibrations of the thiocyanate and isothiocyanate groups

1964 ◽  
Vol 17 (8) ◽  
pp. 838 ◽  
Author(s):  
RA Cummins
Keyword(s):  
Hydrogen Bond ◽  
Frequency Shift ◽  
Mixed Solvent ◽  
Intensity Change ◽  
Solute Interaction ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
Large Frequency ◽  
Phenyl Compounds

The frequency and intensity of the pseudo-antisymmetric -NCS stretching vibration and the -C≡N stretching vibration in -SCN have been measured for the methyl and phenyl compounds of both isomers in a range of solvents. It is shown that the intensity change in the thiocyanates follows a function of the Buckingham type, but that the change in the intensity of the isothiocyanates is complicated by a further effect which could be due to specific solvent/solute interaction. This interaction is reflected in the large frequency shift of the isothiocyanates whereas for the thiocyanates the shift is only very small. However, mixed-solvent studies indicate that the interaction is not strong enough to be classed as a hydrogen bond. Parallel solvent studies on the analogous vibration of the -NCO group indicate that this group, rather surprisingly, is barely solvent-sensitive at all.

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