Knowledge Bank

The microwave spectrum of a carbon-13 isotope of cis-1,2-difluorocyclopropane,$\mathrm{<mrow\; data-mjx-texclass="ORD">\ast </mrow>}CHFCHFCH2$, has been assigned in natural abundance. The normal and deuterium isotopic rotational constants reported $previously1$ were combined with the carbon-13 data to partially determine the molecular structure. The $rs$ parameters are $r(C1C2)=1.488(3)\backslash AA$ and $r(C1,\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}H)=1.093(4)\backslash AA$. These structural parameters will be compared to the trans isomer of 1,2-difluorocyclopropane as well as to related geometrical pairs of fluorinated three-membered rings. The results will also be discussed in terms of recent theoretical studies of these ring systems.