1,n-Radical ions: an ab initio study of racemization and isomerization of the cyclopropane radical cation.
Wayner, Danial D. M.
Boyd, Russell J.
Arnold, Donald R.
MetadataShow full item record
The surfaces for cis-trans isomerization and racemization of the cyclopropane radical cation (I) are detd. using ab initio calcns. Polarization functions and electron correlation have large effects on the relative energies of I. The calcns. support orbital symmetry predictions that conrotatory closure of the 0.0 conformer of I should be preferred. However, even the conrotatory closure has a significant activation barrier. Conformational changes that accompany single methylene rotation are also discussed. These results, relative to ion cyclotron resonance and mass spectral expts., imply that isomerization of I to the 0.0 conformer can occur at energies far below the barrier required to isomerize I to the propylene radical cation. However, the 0.0 conformer of I and the propylene radical cation should display similar reactivities (e.g., deprotonation). Also, contrary to reported esr evidence, I should not exist preferentially in the 90.0 conformation.
Wayner, Danial D. M., Russell J. Boyd, and Donald R. Arnold. 1985. "1,n-Radical ions: an ab initio study of racemization and isomerization of the cyclopropane radical cation.." Canadian Journal of Chemistry 63(12): 3283-3289.