RING PUCKERING VIBRATIONS OF SOME FIVE- AND SIX-MEMBERED RINGS
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Date
1973
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Publisher
Ohio State University
Abstract
The low frequency Raman spectra of 2,3-dihydrofuran, 2,3-dihydrothiophene, 1,4-cyclohexadiene, and 1,3-cyclohexadiene in the gas phase have been obtained. A band at $216 cm^{-1}$ in the 1,4-cyclohexadiene spectrum has been assigned to the ring puckering mode which is consistent only with a $D_{2h}$ (planar) configuration. For each of the other three molecules, a series of Q branches was found in the range 100 - $200 cm^{-1}$ and has been assigned as arising from low frequency ring bending motions which are confirmed by double minimum potential functions. The barriers to planarity were found to be 85, 325, and $1099 cm^{-1}$ for the 2,3-dihydrofuran, 2,3-dihydrothiophene and 1,3-cyclohexadiene molecules, respectively.
Description
Author Institution: Department of Chemistry, University of South Carolina Columbia