Electronic Structure and Unimolecular Reactions of Cyclopropenone Carbonyl Oxide. A Theoretical Study

A theoretical investigation on the lowest singlet and triplet potential energy surfaces of cyclopropenone carbonyl oxide 1 is presented. The calculated equilibrium geometry and dipole moment suggest that 1 possesses a strong zwitterionic character. The energy barrier for the isomerization of 1 to the cyclic isomer dioxirane 2 is computed to be 9.4 kcal/mol. The singlet state of 1 dissociates into cyclopropenone and excited singlet oxygen atom ((1)D), while the triplet state of 1 dissociates yielding oxygen atom in its ground state ((3)P). The dissociation process is endothermic for the singlet state but highly exothermic for the triplet.