Hydroxyl stretching in substituted phenols: An AM1 study

Abstract

Hydroxyl-stretching frequencies ( voH) were estimated for a number of 4-substituted and 2.6disubstituted phenols using the AM I all-valence electron molecular orbital approximation. There was significant correlation between calculated and experimentally observed frequencies with better correlation observed with the gas phase as compared with dilute solution-phase values. Significant Hammett sigma-rho relationships were recorded for the 4-substituted phenols, consistent with experimental observations. The VOH stretching frequency associated with the equilibrium structure of 2,6-di-t-butylphenol was calculated to be 15 cm-' higher than that of phenol and this increase was attributed to steric interactions that act to effectively shorten the OH bond length. 0 1993 John Wiley & Sons, Inc.