Knowledge Bank

The infrared and Raman spectra of fluoromethylcyclopropane and bisoxirane (butadiene bisepoxide) have been recorded. At least two conformers of the d,$\ell$ isomer of bisoxirane exist in the fluid state, but only one conformer, tentatively identified as the trans, exists in the crystalline solid. The second conformer appears to be the gauche form and, from variable temperature data, has been determined to be approximately .2 kcal/mole less stable. Fluoromethylcyclopropane, unlike other halomethylcyclopropanes, is only stable for relatively short periods at ambient temperature. The most stable conformation has the gauche orientation, and, contrary to expectations, there is very little of the second conformer (trans) in the fluid states. Based on all the available spectroscopic data, complete vibrational assignments for both molecules will be proposed and their conformational preferences will be discussed.