Ab initio study of the structures and thermodynamic properties of some gem-disubstituted propyl radicals: The effects of ethyl groups on the stabilization energies of these disubstituted radicals

Abstract

The equilibrium structures and vibrational frequencies of some disubstituted propyl radicals, especially CH 3CH 2C(OH) 2, CH 3CH 2C(NH 2) 2, CH 3CH 2C(CHO) 2, CH 3CH 2C(OH)-(CHO) and CH 3CH 2C(NH 2)(CHO), were studied by ab initio molecular orbital methods. Geometries were optimized at the unrestricted Hartree-Fock (UHF) level of theory for open-shell species, using the 6–31G and 6–31G ∗∗ basis sets. The enthalpies of formation of these radicals were estimated by using the concept of the isodesmic reaction. These data were used to calculate the thermodynamic stabilization energies of these compounds which influence the methyl addition radical reactions to olefins.