Abstract
A series of electrocyclic isomerizations related to the cyclobutene to butadiene reaction have been studied by ab initio theory. In addition to the cyclobutene isomerization, the ring-opening reactions of dioxetene, oxetene, dithiete, and thiete to cis-glyoxal, cis-acrolein, dithioglyoxal, and cis-thioacrolein have been examined. Structures and vibrational frequencies have been determined for reactants, transition states, and products with split-valence and split-valence plus polarization self-consistent field (SCF) methods. For the cyclobutene to butadiene, dioxetene to glyoxal, and oxetene to acrolein reactions, multiconfiguration SCF (MCSCF) geometries were optimized. The use of unrestricted Hartree-Fock natural orbitals (UHF-NO) to define the active space for complete active-space SCF (CASSCF) computations on the transition states was examined. MCSCF, configuration interaction (CISD), and Moller-Plesset perturbation theory (MP4SDTQ) methods were used to determine the activation barriers and reaction energies
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
