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Resonance and field/inductive substituent effects on the gas‐phase acidities of para ‐substituted phenols: a direct approach employing density functional theory
Author(s) -
Barbour Josiah B.,
Karty Joel M.
Publication year - 2005
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.850
Subject(s) - substituent , chemistry , inductive effect , phenols , resonance (particle physics) , phenol , density functional theory , computational chemistry , gas phase , molecule , stereochemistry , medicinal chemistry , organic chemistry , physics , particle physics
Relative gas‐phase acidities of para ‐substituted phenols ( 1 , Sub—C 6 H 4 —OH) and their ω‐substituted para ‐alkylphenol analogs [ 2 , Sub—(CH 2 ) n —C 6 H 4 —OH] were calculated at the B3LYP/6–31+G* and AM1 levels of theory. The acidity of a substituted molecule of 2 is compared with that of the unsubstituted molecule of 2 to determine the field/inductive effect of the substituent on the acidity of 2 . This field/inductive effect was extrapolated to n = 0, yielding the field/inductive effect of the substituent on the acidity of 1 . The derived field/inductive effect in 1 was subtracted from the difference in acidity between 1 and phenol in order to determine the resonance effect of the substituent on the acidity of 1 . Our results are compared with the field/inductive and resonance substituent parameters empirically derived from previous experimental solution studies. Copyright © 2004 John Wiley & Sons, Ltd.