A CCSD(T) INVESTIGATION OF CARBONYL OXIDE AND DIOXIRANE - EQUILIBRIUMGEOMETRIES, DIPOLE-MOMENTS, INFRARED-SPECTRA, HEATS OF FORMATION AND ISOMERIZATION ENERGIES

A CCSD and CCSD(T) investigation of carbonyl oxide (1) and its cyclic isomer dioxirane (2) has been carried out employing DZ + P and TZ + 2P basis sets. Calculated geometries, charge distributions, and dipole m oments suggest that 1 possesses more zwitterionic character (CCSD(T) d ipole moment 4 D) than has been predicted. 1 can be distinguished from 2 by its infrared spectrum as indicated by CCSD (T) frequencies, inte nsities, and isotopic shifts. The heats of formation DELTAH(f)0(298) f or 1 and 2 are 30.2 and 6.0 kcal/mol, respectively; the CCSD(T) barrie r to isomerization from 1 to 2 is 19.2 kcal/mol. Decomposition of 1 an d 2 can lead to CO, CO2, H2O, H-2 but not to free CH2, O2 or O. Both i somers should be powerful epoxidation agents in the presence of alkene s, but they should differ in their ability to form cyclopropanes with alkenes.