Knowledge Bank

The microwave spectrum of cyclopropyl cyanide has been reinvestigated. Previously Friend and $Dailey1$ assigned a-type transitions in the normal and several deuterated species, but had insufficient data for a structural determination. We have assigned c-type transitions allowing determination of the A rotational constant for the normal isotopic species and have assigned a- and c-type transitions for the species containing $\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}C$ in the ring. The ring structure will be discussed in the light of Hoffmann ‘$s2$ theoretical predictions and in comparison with 1, 1-$difluorocyclopropane.3$