Toward the Physical Interpretation of Inductive and Resonance Substituent Effects and Reexamination Based on Quantum Chemical Modeling

An application of a charge of the substituent active region concept to 1-Y,4-X-disubstituted derivatives of bicyclo[2.2.2]octane (BCO) [where Y = NO 2 , COOH, OH, and NH 2 and X = NMe 2 , NH 2 , OH, OMe, Me, H, F, Cl, CF 3 , CN, CHO, COMe, CONH 2 , COOH, NO 2 , and NO] provides a quantitative information on the inductive component of the substituent effect (SE). It is shown that the effect is highly additive but dependent on the kind of substituents. An application of the SE stabilization energy characteristics to 1,4-disubstituted derivatives of BCO and benzene allows the definition of inductive and resonance contributions to the overall SE. Good agreements with empirical approaches are found. All calculations have been carried out by means of the B3LYP/6-311++G(d,p) method.