Knowledge Bank

The infrared spectra of dicyclopropyl ketone and 1,1-dicyclopropylethene have been measured from $4000-200cm-1$ in the liquid and vapor phases. Additionally, Raman spectra of the liquid and polycrystalline solid phases of both compounds have also been recorded. The spectra of the two compounds are consistent with the presence of only the cis-cis conformer (having $C2v$ symmetry) in each case. No indication of other conformers was found. While these results differ slightly from those for similar $molecules,1$ the steric and conjugative effects in these two cases predominate, and dictate the existence of only the cis-cis rotamers. From the spectroscopic data, tentative vibrational assignments have also been proposed for both compounds.