Ring strain energy and enthalpy of formation of oxiranone: an ab initio theoretical determination

The enthalpy of formation ΔHof,298 for oxiranone is estimated as -190 ± 10 kJ mol-1 by means of ab initio molecular orbital calculations at the QCISD(T)full/6-311G(2df,p)//MP2 full/6-311G(d,p) level of theory, corresponding to a conventional ring strain energy of 169 kJ mol-1. The QCISD(T) calculated enthalpy of formation of cyclopropanone is 6.3 kJ mol-1. The oxiranone ring is probably slightly less strained than the cyclopropanone ring.