SUBSTITUTED OXIRENES (X(2)C(2)O, X=BH2, CH3, NH2, OH, F) - CAN THEY BE MADE

The oxirene system has received much attention recently; most theoreti cal studies have concentrated on the unsubstituted molecule while most experimentation has involved substituted oxirenes. In an effort to br idge the information gap between theory and experiment we have underta ken an ab initio study of substituted oxirenes. Predictions at various levels of theory up to the double-zeta plus polarization single and d ouble coupled cluster with perturbative triples correction [DZP CCSD(T )] are presented for the series of substituted oxirenes with the formu la X(2)C(2)O, where X = BH2, CH3, NH2, OH, and F. Predictions from thi s level of theory are thought to be quite dependable on the basis of e arlier work. Stationary points are compared among themselves and with the parent oxirene (X = H) and the molecular orbitals involved in ring bonding are analyzed, providing insight into the nature of the chemic al bonding. Only the dimethyloxirene molecule (in addition to the earl ier reported unsubstituted oxirene) is predicted to be a minimum on th e DZP CCSD(T) surface. All other substituted oxirenes in the series ar e predicted to be transition states at that or lower levels of theory. Preliminary data from a benzooxirene study are also included.