James D. Dill

Geometrical preferences of the crotyl anion, radical and cation

Abstract ab initio MO calculations have been performed on the cis and trans isomers of the crotyl cation, free radical and anion in each of two orientations of the Me rotor about the allylic framework. In agreement with available experimental data, both the crotyl cation and free radical prefer trans skeletal geometries. On the other hand, the cis isomer of the crotyl anion is found to be more stable than the t rans , the same preference as has been noted for alkali metal allyl organometallics in solution, but opposite to that recently reported for the free (gas phase) anion. The Me groups are predicted to eclipse the partial double bond for the trans isomers of all three systems and for the cis cation. These results are rationalized with the aid of perturbation MO theory.

Carbon-beryllium binding in CH2Be

Ab initio molecular orbital theory is used to study carbon-beryllium binding in the lowest singlet and triplet states of CH2Be. When electron correlation is included, both singlet and triplet states are significantly bound relative to the ground states of CH2 and Be fragments.