Ab Initio Study of Methano and Ethano Bridged Derivatives of Oxyallyl

摘要

Ab initio SCF-CI computations on methano and ethano bridged oxyallyl (CH2-CO-CH2) diradical shows that these species are ground state singlet diradicaloids, despite the possibility of being drawn as diradicals with a possible triplet ground spin state. The gap between the excited state triplet and the ground state singlet is 4-7 kcal/mol, depending on the system and on the level of theory used. This study shows that computational theory is of great value in checking the qualitative predictions of diradical ground state spin multiplicity as expressed in a variety of 'back of the envelope' parity-based models. Oxyallyl diradical substitution; Substitution effects; Diradical ground state spin multiplicity; Ab initio molecular orbital; Configuration interaction theory. (jes)