PROTONATED CARBONYL GROUPS: IV. N,N-DIMETHYLACETAMIDE SALTS

1964 ◽  
Vol 42 (12) ◽  
pp. 2721-2727 ◽  
Author(s):  
Denys Cook
Keyword(s):  
Oxygen Atom ◽  
Infrared Spectra ◽  
Deformation Mode ◽  
Carbonyl Groups ◽  
Broad Absorption ◽  
Average Value ◽  
Correlation Field ◽  
Bending Mode ◽  
Out Of Plane ◽  
Transmission Windows

The infrared spectra of N,N-dimethylacelamide salts have been recorded and are consistent with protonation at the oxygen atom, vOH is between 2 095 and 3 360 cm−1 depending on the anion. The average value of the two components of the OH in-plane hydrogen-bending mode, δOH, is 1 253 cm−1 (splitting of about 147 cm−1 due to correlation field effects). The out-of-plane hydrogen-deformation mode occurs at 928 to 761 cm−1 depending on the salt. The 1 680 and 1 400 cm−1 bands which are present in all the salts are associated chiefly with stretching the CN and CO bonds respectively, in the OCN group, though it is likely that the vibrations are somewhat mixed.Some salts of complex acids are of the 2 base: 1 acid variety with very strong broad absorption centered near 900 cm−1, containing sharp transmission windows.

PROTONATED CARBONYL GROUPS: III. ANTIPYRINE SALTS

1963 ◽  
Vol 41 (11) ◽  
pp. 2794-2799 ◽  
Author(s):  
Denys Cook
Keyword(s):  
Hydrogen Atom ◽  
Hydrogen Bonds ◽  
Carbonyl Group ◽  
Infrared Spectra ◽  
Strong Absorption ◽  
Carbonyl Groups ◽  
Correlation Field ◽  
Bending Mode ◽  
Out Of Plane ◽  
Stretching Vibration

Salts of antipyrine (2,3-dimethyl-1-phenyl-5-pyrazolone) with halogen acids have been prepared and their infrared spectra from 4000 to 650 cm−1 recorded. Stoichiometrically they are normal 1:1 salts. Identification of bands due to vibrations of the protonating hydrogen atom has been aided by replacement with deuterium atoms. It is concluded that protonation occurs at the carbonyl group from the presence of a doublet (due to correlation field splitting) at 1320 and 1220 cm−1, attributed to the in-plane hydrogen-bending mode. The OH stretching vibration gives rise to bands between 2278 and 2720 cm−1 in the different salts. Out-of-plane hydrogen-bending mode absorptions are observed between 840 and 770 cm−1.More complex acids (HAsF6 etc.) give the anomalous 2 base:1 acid salts, characterized by strong absorption below 1400 cm−1, which probably contain strong, possibly symmetrical, hydrogen bonds.

Factor Analysis as a Complement to Band Resolution Techniques. III. Self Association in Trichloroacetic Acid

1975 ◽  
Vol 53 (9) ◽  
pp. 1251-1257 ◽  
Author(s):  
J. T. Bulmer ◽  
H. F. Shurvell
Keyword(s):  
Factor Analysis ◽  
Infrared Spectra ◽  
Trichloroacetic Acid ◽  
Linear Polymers ◽  
Carbonyl Groups ◽  
Absorption Coefficients ◽  
Average Value ◽  
Self Association ◽  
Shape Ratio ◽  
Monomer Band

Digitized infrared spectra of nine solutions of trichloroacetic acid in CCl4 have been studied in the carbonyl stretching region. At all concentrations only two bands are visually apparent. However, factor analysis indicates the presence of four absorbing components. The contour resolution technique gives a monomer band at 1786 cm−1, a dimer band at 1749 cm−1, and a third band close to the dimer frequency at approximately 1735 cm−1. Examination of the changes in Cauchy–Gauss shape ratio of the monomer band with increasing concentration indicates the presence of an unresolved component. The band at 1735 cm−1 and the unresolved band near the monomer peak at 1786 cm−1 are assigned to absorption of carbonyl groups in linear polymers of trichloroaceticacid. The monomer–dimer equilibrium constant was calculated from the molar absorption coefficients and absorbances of monomer and dimer bands. The average value over the concentration range 0.305 × 10−3 to 0.1603 M was 287 l/mol at 33.9 ± 0.5 °C.

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.

Infrared Spectra of Polysubstituted Pyrimidines in the 700–200 cm−1 Region

1968 ◽  
Vol 22 (3) ◽  
pp. 170-182 ◽  
Author(s):  
D. A. Netzel ◽  
T. S. Hermann ◽  
F. F. Bentley
Keyword(s):  
Infrared Spectra ◽  
Deformation Mode ◽  
Mass Effects ◽  
Out Of Plane ◽  
Ring Deformation

The infrared spectra of 28 substituted pyrimidines are presented in the 700–200 cm−1 region. These compounds are characterized by the in-plane ring deformation mode near 500 cm−1, and the out-of-plane ring deformation near 450 cm−1. The resonance, inductive, and mass effects on these and on other fundamental modes are also presented.

THE INFRARED SPECTRA OF TRIMETHYLAMINE OXIDE SALTS

1963 ◽  
Vol 41 (5) ◽  
pp. 1127-1134 ◽  
Author(s):  
Denys Cook
Keyword(s):  
Hydrogen Bond ◽  
Infrared Spectra ◽  
Field Coupling ◽  
Correlation Field ◽  
Trimethylamine Oxide ◽  
Bending Mode ◽  
Good Agreement

Several salts of trimethylamine oxide have been prepared. A species common to all these salts, the (CH3)3NOH+ ion, has been inferred from the infrared spectra of the solids, but with varying degrees of interaction in the hydrogen bond [Formula: see text] depending on the anion. These variations have been investigated in detail, and with the help of deuterium replacement, confident assignments for the OH stretching, bending, and torsional modes have been made. A splitting of about 80 cm−1 in the bending mode has been noted, and has been ascribed to correlation field coupling. With one exception, the assignments are in good agreement with those previously determined by Giguère and Chin.

Crush Behavior of Corrugated Cores Sandwich Panels

2011 ◽  
Vol 217-218 ◽  
pp. 1584-1589 ◽  
Author(s):  
Yan Chang Zhang ◽  
Shi Lian Zhang ◽  
Zi Li Wang
Keyword(s):  
Energy Absorption ◽  
Deformation Mode ◽  
Absorption Characteristic ◽  
Element Analysis ◽  
Dynamic Finite Element Analysis ◽  
Fe Simulations ◽  
Bending Mode ◽  
Out Of Plane ◽  
Resistance Performance ◽  
Deformation Modes

The out-of-plane quasi-static compressive behavior of four types of corrugated cores (V-type, U-type, X-type and Y-type core) has been investigated by experiment and FE simulations. By transient dynamic finite element analysis code MSC.Dytran numerical simulations were performed for calculating crushing forces, deformation mode and energy absorption. The FE simulations predict the crush behavior of cores with reasonable accuracy and provide the whole progressive buckling process and deformation modes. Experiment and simulation indicate that the U-type core, V-type core and X-type core structures show excellent crushing resistance performance and energy absorption characteristic. The crush performance of the Y-type core structures is relatively poor because of bending mode.

PROTONATED CARBONYL GROUPS: V. α-PYRIDONE SALTS

1965 ◽  
Vol 43 (4) ◽  
pp. 749-757 ◽  
Author(s):  
Denys Cook
Keyword(s):  
Carbonyl Group ◽  
Infrared Spectra ◽  
Carbonyl Groups ◽  
Bending Vibrations ◽  
Out Of Plane ◽  
Plane Bending ◽  
Strong Acids

Salts of 1-methyl-2-pyridone and 1-methyl-2-quinolone with strong acids have been prepared and their infrared spectra recorded between 4 000 and 650 cm−1. Protonation of the carbonyl group occurs giving rise to OH stretching, in-plane and out-of-plane bending vibrations which absorb in characteristic regions of the spectrum, namely 1 900 – 3 300 cm−1 (depending on the anion), ~ 1 250 cm−1, and ~ 800 cm−1 respectively, with appropriate shifts on deuteration. Other tentative assignments are made.

PROTONATED CARBONYL GROUPS II. γ-PYRIDONE SALTS

1963 ◽  
Vol 41 (10) ◽  
pp. 2575-2584 ◽  
Author(s):  
Denys Cook
Keyword(s):  
Nitrogen Atom ◽  
Oxygen Atom ◽  
Organic Cation ◽  
Deformation Mode ◽  
Carbonyl Oxygen ◽  
Carbonyl Groups ◽  
Hydrated Form ◽  
Strong Band ◽  
Mineral Acids ◽  
Hydrogen Bonded

The salts of 1,2,6-trimethyl-4-pyridone and 1-ethyl-2,6-dimethyl-4-pyridone and mineral acids and their deuterated analogues have been prepared and their spectra recorded. The spectra are consistent with protonation at the carbonyl oxygen atom, not the nitrogen atom. Many similarities with the spectra of γ-pyrone salts (D. Cook. Can. J. Chem. 41, 505 (1963)) have been observed, voh varies from 2495 cm−1 in the HCl salt to 3470 cm−1 in the HPF6 salt. The deformation mode, vOH, is much more constant in frequency and is doubled, near 1300 and 1230 cm−1, probably due to correlation field splitting. A few of the more strongly hydrogen-bonded salts have torsional modes around 800 cm−1.Many of the salts can also be prepared in a hydrated form which contains the same organic cation, probably hydrogen bonded to chains of water molecules.In one case a salt containing 2 molecules of the base to 1 of acid (HAsF6) has been prepared. The spectrum contains a very broad, strong band, near 1300 cm−1, probably due to the species [Formula: see text].

scholarly journals Microcrack Detection Using Spectral Response Data Alone

2021 ◽  
Vol 11 (8) ◽  
pp. 3655
Author(s):  
Gee-Soo Lee ◽  
Chan-Jung Kim
Keyword(s):  
Spectral Response ◽  
Coherence Function ◽  
Cold Forming ◽  
Response Data ◽  
Highly Sensitive ◽  
Bending Mode ◽  
Out Of Plane ◽  
Rectangular Specimen ◽  
Microcrack Detection ◽  
Impulse Force

Microcracks of depth less than 200 μm in mechanical components are difficult to detect because conventional methods such as X-ray or eddy current measurements are less sensitive to such depths. Nonetheless, an efficient microcrack detection method is required urgently in the mechanical industry because microcracks are produced frequently during cold-forming. The frequency response function (FRF) is known to be highly sensitive even to microcracks, and it can be obtained using both the input data of an impact hammer and the response data of an accelerometer. Under the assumption of an impulse force with a similar spectral impulse pattern, spectral response data alone could be used as a crack indicator because the dynamic characteristics of a microcrack may be dependent solely on these measured data. This study investigates the feasibility of microcrack detection using the response data alone through impact tests with a simple rectangular specimen. A simple rectangular specimen with a 200 μm microcrack at one face was prepared. The experimental modal analysis was conducted for the normal (uncracked) specimen and found-first bending mode about 1090 Hz at the X-Y plane (in-plane). Response accelerations were obtained in both at in-plane locations as well as X-Z plane (out-of-plane), and the crack was detected using the coherence function between a normal and a cracked specimen. A comparison of the crack inspection results obtained using the response data and the FRF data indicated the validity of the proposed method.

Infrared Spectra of Some Chloro Derivatives of s-Triazine

1966 ◽  
Vol 20 (3) ◽  
pp. 159-160 ◽  
Author(s):  
T. S. Herman
Keyword(s):  
Infrared Spectra ◽  
Triazine Ring ◽  
Chlorine Atoms ◽  
Vibrational Assignments ◽  
Fundamental Frequencies ◽  
Bending Mode ◽  
Chloro Derivatives ◽  
Derivatives Of

The effects of chlorine atoms on the fundamental frequencies of the s-triazine ring are discussed and the vibrational assignments in the region 1600–700 cm−1 are extended. The variation in the position of the C3N3-ring bending mode in the region near 810 cm−1 is discussed.

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