Polarized infrared spectra of oriented polycrystalline films. Intermolecular vibrational coupling in crystalline 2,4,6‐tribromoaniline

1983 ◽  
Vol 79 (1) ◽  
pp. 1-8 ◽  
Author(s):  
R. M. P. Jaiswal ◽  
J. E. Katon ◽  
G. N. R. Tripathi
Keyword(s):  
Infrared Spectra ◽  
Polycrystalline Films ◽  
Vibrational Coupling ◽  
Oriented Polycrystalline

THE INFRARED SPECTRA OF MALONATES AND OXALATES: TEMPERATURE EFFECT

1959 ◽  
Vol 37 (7) ◽  
pp. 1146-1152 ◽  
Author(s):  
R. A. Abramovitch
Keyword(s):  
Carbon Tetrachloride ◽  
Temperature Effect ◽  
Infrared Spectra ◽  
Temperature Effects ◽  
Liquid Films ◽  
Vibrational Coupling ◽  
Rotational Isomers ◽  
Acetonitrile Solutions ◽  
Definite Temperature

The infrared spectra of a number of malonates and oxalates (as liquid films) were examined at various temperatures and narrower slit widths than had previously been used. The absorption in the 5.8 μ region is very complex, at least four bands being observed in each case. Small but definite temperature effects were recorded for both types of esters. At somewhat wider slit widths only two bands were observed, these occasionally having indistinct shoulders. The spectra of some of the compounds were also measured in both carbon tetrachloride and acetonitrile solutions (two bands observed in each case) and the ratios of the intensities of the two bands compared. A possible explanation of the effects observed is that at least two rotational isomers can exist for each compound and that vibrational coupling of the carbonyl stretching frequencies can occur in each of the rotational isomers.

The wavenumbers of C=O stretching vibrations of maleinimides

1985 ◽  
Vol 50 (6) ◽  
pp. 1305-1311 ◽  
Author(s):  
Alexander Perjéssy ◽  
Manfred Augustin ◽  
Manfred Köhler
Keyword(s):  
Experimental Data ◽  
Infrared Spectra ◽  
Linear Correlation ◽  
Vibrational Coupling ◽  
Stretching Vibrations

The infrared spectra in the region of fundamental C=O stretching vibrations in tetrachloromethane and chloroform were measured for 59 maleinimide derivatives. A linear correlation between the wavenumbers of symmetric and antisymmetric C=O stretching vibrations was found for a series of 102 experimental data obtained in both solvents. The slope of the νs(C=O) vs νas(C=O) dependence as well as the degree of the vibrational coupling in imide system were discussed and compared with those for analogical five-membered cyclic 1,3-diketones.

Oriented Polycrystalline Films for Infrared Spectroscopic Studies

1985 ◽  
Vol 39 (2) ◽  
pp. 273-278 ◽  
Author(s):  
J. M. Landry ◽  
J. E. Katon ◽  
J. M. Hughes
Keyword(s):  
Spectroscopic Studies ◽  
Polycrystalline Films ◽  
Infrared Spectroscopic ◽  
Oriented Polycrystalline

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.

Infrared Studies of Water in Crystalline Hydrates: K2CuCl4•2H2O

1974 ◽  
Vol 52 (7) ◽  
pp. 1029-1041 ◽  
Author(s):  
Gwen H. Thomas ◽  
Michael Falk ◽  
Osvald Knop
Keyword(s):  
Crystal Structure ◽  
Water Molecule ◽  
Infrared Spectra ◽  
Vibrational Spectra ◽  
Distinct Type ◽  
Vibrational Coupling ◽  
Infrared Studies ◽  
Crystalline Hydrates

Infrared spectra of polycrystalline K2CuCl4•2H2O at different degrees of deuteration were recorded, between 4000 and 300 cm−1, at temperatures from −160 to 90 °C. The spectra confirm the existence of only one crystallographically distinct type of water molecule in the structure, on sites of symmetry C2r. Vibrational coupling of the bending fundamentals of the water molecule has been analyzed in detail. It is shown that the existence and magnitude of such coupling may be used to predict, from the spectrum of a hydrate, the manner in which a water molecule participates in the crystal structure. The structure and the vibrational spectra of K2CuCl4•2H2O are compared with those of the closely related CuCl2•2H2O.

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