An MNDO-effective charge model study of the solvent effect: The internal rotation about partial double bonds and the nitrogen inversion in amine

Abstract The effective charge model, which introduces the solvent effect into MO calculation, was incorporated with the MNDO—MO method. One-center solvation energy associated with the atom having the fractional charge was evaluated empirically by Born's formula, while the two-center values by Ohno—Klopman like equation. The atomic radius was varied as the function of the atomic charge. The method reproduced well the observed solvent effect on the barrier to internal rotation of formamide, 4-aminopyrimidine, furfuraldehyde and the amidinium ion, and the barrier to nitrogen inversion in amine.

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