In this study, we calculate the stabilization of β-substituted ethyl cations (R = H, Li, BeH, BH_2, CH_3, NH_2, OH, F, Na, MgH, AlH_2, SiH_3, PH_2, SH, Cl) and α-substituted methyl cations (R = H, Li, CH_3, NH_2, OH, F, Na, SiH_3, PH_2, SH, Cl) in order to obtain a relationship between the nature of the substituent and the degree of stabilization of the cation. Results show that the stabilization energy is related to the electronegativity of the β substituents, but not the α substituents. The rotational barrier of the β-substituted ethyl cation is linearly related to the Mulliken population of the 2p(C+) orbital. We found that the stabilization energy is linearly related to the ionization potential of the α- and PLA β-substituted radicals, and the HOMO energies of the PLA β-substituted radical are linearly related to the corresponding ionization potentials. Trends in the stabilization by second- and third-row substituents are discussed.
© 1988 American Chemical Society
White, J.A.; Cave, R.J.; Davidson, E.R. “An Ab Initio Investigation of the Stabilization of Selected β- and α- substituted Ethyl and Methyl Cations," J. Am. Chem. Soc. 1988, 110, 6308. DOI: 10.1021/ja00227a005