The Vibrational Spectra of α-Bromoacetaldehyde Dimethyl Acetal and Related Molecules

1975 ◽  
Vol 29 (6) ◽  
pp. 501-506 ◽  
Author(s):  
J. E. Katon ◽  
Philip D. Miller
Keyword(s):  
Liquid Phase ◽  
Infrared Spectra ◽  
Vibrational Spectra ◽  
Low Temperatures ◽  
Conformational Equilibrium ◽  
Dimethyl Acetal ◽  
Vibrational Assignment ◽  
Crystal State ◽  
Apparent Evidence

The complete vibrational spectra of α-bromoacetaldehyde dimethyl acetal and α-bromoacetaldehyde dimethyl s6 have been recorded on the pure liquids, and a tentative vibrational assignment has been proposed. The infrared spectra of both compounds in the crystal state have also been recorded at low temperatures. There is no apparent evidence of a conformational equilibrium in the liquid phase. The infrared spectra of three other acetals have been recorded, and the data from all of the compounds are discussed in terms of previously proposed group frequencies of acetals in both the infrared and Raman.

The Vibrational Spectra and Structure of Dimethyl Carbonate and its Conformational Behavior

1975 ◽  
Vol 53 (9) ◽  
pp. 1378-1386 ◽  
Author(s):  
J. E. Katon ◽  
M. D. Cohen
Keyword(s):  
Liquid Phase ◽  
Infrared Spectra ◽  
Dimethyl Carbonate ◽  
Solid Phase ◽  
Equilibrium Mixture ◽  
Vibrational Assignment ◽  
Enthalpy Difference ◽  
Oriented Polycrystalline ◽  
Phase Data ◽  
Liquid And Solid Phases

The infrared spectra of dimethyl carbonate in the liquid and solid phases and the Raman spectrum of the liquid phase are reported. The evidence suggests that dimethyl carbonate exists as an equilibrium mixture of at least two conformers in the liquid state. An experimental value for the enthalpy difference of the two conformers of 2.6 ± 0.5 kcal/mol is obtained from the temperature dependency of the infrared spectrum.Dimethyl carbonate crystallizes as an oriented polycrystalline film and polarized infrared spectra of the solid have been obtained. These have been utilized, along with the liquid phase data to obtain an improved vibrational assignment. There appears to be a solid–solid phase change in dimethyl carbonate in the vicinity of 140 K, but the details of this change are not known.

THE VIBRATIONAL SPECTRA OF ACETALDEHYDE AND ACETALDEHYDE-d1

1956 ◽  
Vol 34 (8) ◽  
pp. 1083-1092 ◽  
Author(s):  
J. C. Evans ◽  
H. J. Bernstein
Keyword(s):  
Raman Spectra ◽  
Infrared Spectra ◽  
Vibrational Spectra ◽  
Vibrational Assignment ◽  
Depolarization Ratios

The Raman spectra of liquid CH3CHO and CH3CDO were obtained photo-electrically and depolarization ratios measured. Infrared spectra of the vapors and solids were also obtained. A vibrational assignment is given and the spectra correlated. The vibrational spectra of the acetyl halides reported in the literature are also correlated.

Conformational Isomerism and Oriented Polycrystal Formation of Dimethyl Carbonate

1974 ◽  
Vol 52 (10) ◽  
pp. 1994-1996 ◽  
Author(s):  
J. E. Katon ◽  
Mark D. Cohen
Keyword(s):  
Liquid Phase ◽  
Infrared Spectra ◽  
Alkali Halide ◽  
Dimethyl Carbonate ◽  
Conformational Equilibrium ◽  
Equilibrium Mixture ◽  
Polycrystalline Film ◽  
Conformational Isomerism ◽  
Enthalpy Difference ◽  
Oriented Polycrystalline

It has been found that dimethyl carbonate exists in the liquid phase as a conformational equilibrium mixture. The conformers differ by rotation about the C—O bonds. The enthalpy difference of the two conformers is found experimentally to be 2.6 ± 0.5 kcal/mol. Dimethyl carbonate crystallizes in contact with alkali halide windows as an oriented polycrystalline film, as shown by polarized infrared spectra.

Infrared and Raman spectra and vibrational assignment of methylene cyclopropane-h6 and -d6

1970 ◽  
Vol 48 (24) ◽  
pp. 3889-3902 ◽  
Author(s):  
J. E. Bertie ◽  
M. G. Norton
Keyword(s):  
Liquid Phase ◽  
Gas Phase ◽  
Raman Spectra ◽  
Infrared Spectra ◽  
Infrared And Raman Spectra ◽  
Vibrational Assignment ◽  
Isotope Shifts ◽  
Liquid Phases ◽  
Modes Of Vibration ◽  
Depolarization Ratios

Infrared spectra have been recorded in the range 4000 to 20 cm−1 for methylene cyclopropane-h6 and -d6 in the gas phase, and from 4000 to 200 cm−1 for methylene cyclopropane-h6 in the liquid phase. Raman spectra have been recorded for the liquid phases of both species. The fundamental modes of vibration have been assigned using i.r. band contours and Raman depolarization ratios, with the exception of the i.r. inactive A2 modes which were not observed. An interesting feature is the occurrence of remarkably small isotope shifts for certain modes.

scholarly journals THE VIBRATIONAL SPECTRA OF ISOBUTANE AND ISOBUTANE-d1

1956 ◽  
Vol 34 (8) ◽  
pp. 1037-1045 ◽  
Author(s):  
J. C. Evans ◽  
H. J. Bernstein
Keyword(s):  
Raman Spectra ◽  
Infrared Spectra ◽  
Vibrational Spectra ◽  
Vibrational Assignment ◽  
Depolarization Ratios

The Raman spectra of liquid (CH3)3CH and (CH3)3CD were obtained photo-electrically and intensities and depolarization ratios measured. The infrared spectra of the corresponding gases were obtained from 3 to 35 μ. A vibrational assignment consistent with depolarization ratios and band contours has been made for the molecules on the basis of C3ν symmetry and their spectra correlated.

The Vibrational Spectra of Methyl Cyanoacetate and Methyl Cyanoacetate-d3

1974 ◽  
Vol 52 (17) ◽  
pp. 3057-3062 ◽  
Author(s):  
Deepali Sinha ◽  
J. E. Katon
Keyword(s):  
Liquid Phase ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Vibrational Assignment ◽  
Conformational Isomers ◽  
Solid Phases ◽  
Liquid And Solid Phases

The i.r. spectra of methyl cyanoacetate in both liquid and solid phases and of methyl cyanoacetate-d3 in the liquid phase have been recorded in the region 4000–250 cm−1. The Raman spectra of both the compounds in the liquid phase have also been recorded. A tentative vibrational assignment has been made both for the light and the heavy ester. Evidence is presented for the existence of conformational isomers in the liquid phase.

THE VIBRATIONAL SPECTRA OF PYRIDINE, PYRIDINE-4-d, PYRIDINE-2,6-d2, AND PYRIDINE-3,5-d2

1957 ◽  
Vol 35 (10) ◽  
pp. 1183-1194 ◽  
Author(s):  
J. K. Wilmshurst ◽  
H. J. Bernstein
Keyword(s):  
Raman Spectra ◽  
Infrared Spectra ◽  
Thermodynamic Functions ◽  
Vibrational Spectra ◽  
Vibrational Assignment ◽  
Vapor State ◽  
Depolarization Ratios

The infrared spectra of pyridine and pyridine-4-d in the vapor state and of pyridine-2,6-d2 and pyridine-3,5-d2 in the liquid and vapor states have been obtained. The Raman spectra of pyridine-4-d, pyridine-2,6-d2, and pyridine-3,5-d2 as liquids have also been obtained together with depolarization ratios. The vapor band contours for pyridine support the assignment of Corrsin, Fax, and Lord in most part in preference to the assignment of McCullough and co-workers but it was found necessary to reassign the b2 frequencies to give agreement between calculated and observed thermodynamic functions. The infrared and Raman data on pyridine-4-d are in agreement with the reported assignment for the a1, a2, and b1 modes but it was found necessary to reassign the b2 frequencies consistent with the present assignment in pyridine. A complete vibrational assignment for pyridine-2,6-d2 and pyridine-3,5-d2 has been made consistent with the present assignment in pyridine.

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