The νCO absorption of ketones in cooled solution

1976 ◽  
Vol 54 (1) ◽  
pp. 31-36 ◽  
Author(s):  
J. Weinman ◽  
M. Mailloux ◽  
S. Weinman
Keyword(s):  
Infrared Spectra ◽  
Molecular Association ◽  
Lower Frequencies

The infrared spectra of diluted solutions of acetone, acetone-d6, cyclopentanone, cyclopentanone-d4, and cyclohexanone have been measured in the C=O stretching region from 290 to 90 K. As the solutions are cooled, several new bands appear at lower and lower frequencies. An interpretation of these spectra is given in terms of molecular association and anharmonic resonances.

ORGANOGERMANIUM COMPOUNDS: PART II. INFRARED SPECTRA OF SOME ACOXYGERMANES AND THE RELATIVE INDUCTIVE EFFECTS OF TRIMETHYLSILYL AND TRIMETHYLGERMYL GROUPS

1963 ◽  
Vol 41 (5) ◽  
pp. 1244-1249 ◽  
Author(s):  
T. N. Srivastava ◽  
M. Onyszchuk
Keyword(s):  
Gas Phase ◽  
Infrared Spectra ◽  
Absorption Bands ◽  
Organogermanium Compounds ◽  
Inductive Effects ◽  
Electron Release ◽  
Carbonyl Absorption ◽  
Lower Frequencies

The infrared spectra of GeH3OCOCH3 and (CH3)3GeOCOCH3 have been measured in the gas phase over the range 650–3900 cm−1. Assignments for the principal bands have been made and their values compared with those of analogous alkyl, methylsilyl, methyltin, and methyllead acetates. Carbonyl absorption bands shift to lower frequencies and carbon–oxygen (skeletal) absorptions to higher frequencies as M changes from C to Si to Ge in the series of acetates represented by (CH3)3MOCOCH3. These results suggest that the Ge—O bond is more polar than the Si—O bond and that the order of electron release in acetate derivatives is (CH3)3Ge > (CH3)3Si > (CH3)3C, which is consistent with the electronegativity order: C > Si > Ge.

H2O, HDO, and CH3OH Infrared Spectra and Correlation with Solvent Basicity and Hydrogen Bonding

1971 ◽  
Vol 49 (6) ◽  
pp. 837-856 ◽  
Author(s):  
D. N. Glew ◽  
N. S. Rath
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Infrared Spectra ◽  
Dibasic Acid ◽  
Tertiary Amines ◽  
Type Symmetry ◽  
Solvent Basicity ◽  
Organic Amines ◽  
Lower Frequencies ◽  
Hydrogen Bonded

A study has been made of the infrared O—H bands for CH3OH, DOH, and H2O in solution and of their correlation with hydrogen bonding and solvent basicity. Infrared bands for the three fundamentals and the first bending overtone of H2O and for the O—H stretching fundamentals of DOH and CH3OH have been measured between 30 and −40 °C in a solvent range extending from weakly interacting fluorocarbons to strongly hydrogen-bonding organic amines. The O—H stretching bands for the weakly acidic solutes CH3OH, DOH, and H2O are mostly Lorentzian in shape and move to lower frequencies with higher extinctions in the more basic solvents. Many correlations are found between the stretching frequencies and band areas, and between the frequencies and solvent basicity. Monofunctional CH3OH is found to be a stronger acid and forms stronger hydrogen-bonds with a given base than do the doubly bonded DOH and HOH which show equal dibasic acid strengths.The wide, overlapped, fundamental stretching bands for H2O strongly hydrogen-bonded to the tertiary amines and for ice have been partially resolved and unequivocally assigned, showing that there is no cross-over of the ν 3 and ν1 bands despite the strong hydrogen-bonding.At higher temperatures in solvents containing both hydrophobic and strongly basic groups water was found with the lower Cs type symmetry, in which unbonded O—H groups gave sharp bands in the 3680–3650 cm−1 region in addition to the wide hydrogen-bonded bands at lower frequencies.

INFRARED SPECTRA OF COMPLEXES OF 4-PYRIDONES

1963 ◽  
Vol 41 (2) ◽  
pp. 515-521 ◽  
Author(s):  
Denys Cook
Keyword(s):  
Nitrogen Atom ◽  
Carbonyl Group ◽  
Lewis Acid ◽  
Infrared Spectra ◽  
Lewis Acids ◽  
Donor Site ◽  
Acid Strength ◽  
Ring Mode ◽  
Lower Frequencies

The infrared spectra of many complexes of Lewis acids with some 4-pyridones have been recorded. Large shifts to lower frequencies of about 100 cm−1 have been observed in a band near 1560 cm−1 as the Lewis acid strength increased. Much smaller shifts of about 5 to 10 cm−1 in a band near 1640 cm−1 were noted. The former band has therefore been designated as the carbonyl frequency, and the latter as a ring mode involving CC stretching.The donor site of 4-pyridones is therefore the carbonyl group, and not the nitrogen atom. Protonated 4-pyridones have similar spectra, and are consistent with O-, not N-protonation.

HYDROGEN BONDING IN THE AMINE HYDROHALIDES: II. THE INFRARED SPECTRUM FROM 4000 TO 2200 CM−1

1960 ◽  
Vol 38 (1) ◽  
pp. 34-44 ◽  
Author(s):  
C. Brissette ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Infrared Spectrum ◽  
Infrared Spectra ◽  
Primary Amine ◽  
Lithium Fluoride ◽  
Aliphatic Amine ◽  
Combination Bands ◽  
Lower Frequencies ◽  
Amine Salts

The infrared spectra of a number of amine hydrohalides have been measured in the lithium fluoride region.Hydrogen bonding and the torsional oscillations of the [Formula: see text] groups influence these spectra characteristically. The [Formula: see text] stretching frequencies give broad or fairly broadbands. They are near 3000 cm−1 for aliphatic primary amine salts. The corresponding band lies at somewhat lower frequencies for secondary amine salts and much lower for tertiary ones. The aromatic amine hydrohalides exhibit these bands at lower frequencies than do the aliphatic amine salts of the same order. There is a shift to higher frequencies in the series hydrochloride, hydrobromide, hydriodide.All these spectra contain a number of sharper bands which may or may not coincide with the hydrogen-bonded stretching bands. These are combination bands involving mainly deformation vibrations, and they shift to lower frequencies, throughout the series hydrochloride, hydrobromide, hydriodide.The importance of electrical anharmonicity for the appearance of these bands is stressed.The hydrogen bonds in amine hydrohalides appear to be largely electrostatic in character.

The influence of pressure on the infrared spectra of hydrogen-bonded solids. VI. Ammonium salts

1978 ◽  
Vol 31 (1) ◽  
pp. 11 ◽  
Author(s):  
SD Hamann
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Infrared Spectra ◽  
Ammonium Salts ◽  
Bond Strengths ◽  
As If ◽  
Lower Frequencies ◽  
Hydrogen Bonded

The infrared spectra of 33 polycrystalline ammonium salts have been measured at 25°C, at pressures up to 45 kbar. The N-H stretching and bending bands of the hydrogen-bonded NH4+ ions of most of the salts shift anomalously to higher and to lower frequencies, respectively, as the pressure is raised. In this sense, the salts behave as if they had very strong hydrogen bonds, instead of quite weak ones. ��� A fairly good correlation exists between the N-H stretching frequencies of salts with N+-H...O bonds and their hydrogen bond strengths as measured by the minimum N+...O distances in their crystals.

Infrared Spectra, Molecular Weights, and Molecular Association of Chlorophyllsaandb,Methyl Chlorophyllides, and Pheophytins in Various Solvents

1963 ◽  
Vol 85 (23) ◽  
pp. 3801-3809 ◽  
Author(s):  
J. J. Katz ◽  
G. L. Closs ◽  
F. C. Pennington ◽  
M. R. Thomas ◽  
H. H. Strain
Keyword(s):  
Infrared Spectra ◽  
Molecular Association ◽  
Molecular Weights

Studies on metal hydroxy compounds. IV. Infrared spectra of cadmium derivatives Cd(OH)2, CdOHCl, and CdOHF

1967 ◽  
Vol 45 (24) ◽  
pp. 3199-3201 ◽  
Author(s):  
O. K. Srivastava ◽  
E. A. Secco
Keyword(s):  
Infrared Spectra ◽  
Strong Absorption ◽  
Lattice Vibrations ◽  
Absorption Bands ◽  
Simple Molecule ◽  
Stretching Vibration ◽  
Hydroxy Compounds ◽  
First Time ◽  
Lower Frequencies

Infrared spectra of hexagonal Cd(OH)2, CdOHCl, and CdOHF, along with deuterated analogues CdODCl and CdODF, in the range 2.5–16 μ are reported for the first time. The effects of substituting a halogen for an OH group in Cd(OH)2 are (i) shift of OH stretching vibration to a lower frequency and (ii) appearance of strong absorption bands in the region 8–16 μ. All the observed bands in the deuterated analogues are displaced to lower frequencies with νH/νd ratios between 1.35–1.37. The spectra of CdOHCl and CdOHF show a high correlation with their zinc analogues and although both spectra appear consistent with a simple molecule of Cs or C1 symmetry, an alternate interpretation is given in terms of OH lattice vibrations.

Infrared spectra of carbon monoxide on platinum, iridium and copper ; comparison of flat and rough surfaces

1981 ◽  
Vol 78 ◽  
pp. 927-932 ◽  
Author(s):  
F.J.C.M. Toolenaar ◽  
G.J. van der Poort ◽  
F. Stoop ◽  
V. Ponec
Keyword(s):  
Carbon Monoxide ◽  
Infrared Spectra ◽  
Rough Surfaces
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