Vibrational spectra and rotational isomerism of bis(N-2-chloroethyl)nitramine

Autor: L. V. Khristenko, Lev V. Vilkov, E. Yu. Ivanova, L. F. Shishkov, N. F. Pyatakov, Svein Samdal, Yu. A. Pentin
Rok vydání: 1997
Předmět:
Zdroj: Journal of Structural Chemistry. 38:244-256
ISSN: 1573-8779
0022-4766
Popis: The IR and Raman spectra of bis(N-2-chloroethyl)nitramine (BCENA) in the liquid and crystalline states and in CCl4 and CH3CN solutions are studied. The spectra are compared, and it is concluded that BCENA exists as a mixture of conformers of different polarities in the liquid state and as one less polar conformer in the crystalline state. To determine the conformations corresponding to the total electron energy minima and interpret the vibrational spectrum of BCENA, we performed an ab initio quantum chemical calculation of the BCENA molecule in the Hartree-Fock approximation using the 3–21G* and 6–31G* basis sets. Out of twelve possible conformations five are stable; the most stable conformer is C2(GG). The frequencies and forms of normal vibrations of stable conformers are calculated using scaled quantum chemical force fields. The calculated and experimental frequencies are compared, and the relations between the frequencies of skeletal stretching and bending vibrations are analyzed. It is concluded that the BCENA crystal is formed by the C2 (GG) conformer. The vibrational spectrum is interpreted, and the frequencies are assigned to vibrations of conformers differing in form.
Databáze: OpenAIRE
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