A computational study of 2,5-dibenzylidenecyclopentanone and 2,6-dibenzylidenecyclohexanone, model compounds for poly(arylidenecycloalkanones)

The relative energies of the three possible isomers of 2,5-dibenzylidenecyc lopentanone and of 2,6-dibenzylidenecyclohexanone were calculated using Mec hanics, MOPAC, and MOPAC with CI. The calculated lowest energy isomer of ea ch compound agrees with known spectroscopic and crystallographic data. This work shows that the "SCF- CI" calculations previously reported on 2,5-dibe nzylidenecyclopentanone do not predict the actual structure of the compound and should not be used to predict the structure of the corresponding polym er. (C) 1999 John Wiley & Sons, Inc.