AM1/CI 3×3 studies on the combination reactions of methylsubstituted allyl radicals

Abstract

The combination reactions of some methyl-substituted allyl radicals with H-atoms and the methyl radicals were studied by means of a semiempirical quantum-chemical method, on the level of AM1, including the configuration interaction (CI 3×3). The calculated C−H bond dissociation energies differed from the experimental ones by only ca. 10–15 kJ mol−1. The difference in the dissociation energies of the C−H bonds in the allyl positions in i-butene and trans-2-butene was found to be 31.4 kJ mol−1, which is 18.4 kJ mol−1 greater than the experimental value. The activation energies for the combinations of allyl-type radicals studied were found to be zero.