SYNTHESIS, MICROWAVE-SPECTRUM, AND ABINITIO CALCULATIONS FOR DIFLUOROCYCLOPROPENONE

Difluorocyclopropenone was prepared by gas-phase photolysis of difluoromaleic anhydride and was characterized spectroscopically. It is unstable at room temperature but may be stored for long periods of time at -78-degrees-C. Microwave spectra of the normal and O-18 isotopomer for difluorocyclopropenone were measured. The structural parameters were determined to be r(C1O) = 1.192 angstrom, r(C1C2) = 1.453 angstrom, r(C2C3) = 1.324 angstrom, and r(CF) = 1.314 angstrom, and the electric dipole moment was found to be 2.32 D. Ab initio calculations at the CISD/6-31G* level are reported for cyclopropenone, difluorocyclopropenone, and related cyclopropenes and are in good agreement with the experimental results. The experimental geometry and ab initio computations indicate that difluorocyclopropenone enjoys a resonance energy comparable to that of the parent compound.