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Vibrational spectra and bonding in nitrocyclopropane
Author(s) -
Holtzclaw J. R.,
Harris W. C.,
Bush S. F.
Publication year - 1980
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250090409
Subject(s) - raman spectroscopy , chemistry , conformational isomerism , infrared spectroscopy , infrared , vapor phase , substituent , spectral line , cyclopropane , phase (matter) , analytical chemistry (journal) , atomic orbital , ring (chemistry) , molecular physics , molecule , stereochemistry , optics , organic chemistry , physics , thermodynamics , quantum mechanics , astronomy , electron
Raman spectra of nitrocyclopropane were recorded from 4000 to 30 cm −1 for the liquid and solid states. Infrared spectra were recorded from 4000 to 180 cm −1 for vapor phase and matrix isolated states. The low frequency torsional mode is located at 101 cm −1 in the liquid state (102 cm −1 in the solid state) and correlates well with the 84 cm −1 value for the vapor phase which is predicted on the basis of a torsional combination band in the infrared vapor phase spectrum. The calculated barrier to internal rotation for the vapor phase is 1645±50 cm −1 , 4.70±0.15 kcal mol −1 . A vibrational assignment is proposed for the first time and it supports structural arguments that there is significant pseudo‐conjugation between the cyclopropane ring orbitals and the substituent NO 2 group. Finally, a detailed temperature study reveals no appreciable spectral change; hence, nitrocyclopropane appears to exist as a single C s conformer over the range −173 to 100°C.