Ab initio studies of the reactive intermediates involved in the oxidation of acetylenes

The relative stability, zero-point energy, dipole moment and characteristic frequencies of substituted phenylketene isomers, α-ketocarbonyl oxides, dioxetenes and carbynes proposed in the oxidation of acetylenes have been studied by the ab initio method using the split-valence plus polarization 6-31G∗ basis set. Potential barriers for intramolecular rearrangement pathways are calculated for appropriate transition structures in the singlet surface for phenylketene isomers. Alkoxy and phenoxyvinylidenes are found to be the most unstable species. Biradical α-ketocarbonyl oxide is found to be more stable than its isomers. Dioxetene is more stable than its zwitterion isomers and perepoxide.