A. K. Chandra, T. Uchimaru
Apr 25, 2002
Citations
0
Influential Citations
128
Citations
Quality indicators
Journal
International Journal of Molecular Sciences
Abstract
Abstract: The accurate O-H bond dissociation enthalpies for a series of meta and para substituted phenols (X-C 6 H 4 -OH, X=H, F, Cl, CH 3 , OCH 3 , OH, NH 2 , CF 3 , CN, and NO 2 ) have been calculated by using the (RO)B3LYP procedure with 6-311G(d,p) and 6-311++G(2df,2p) basis sets. The proton affinities of the corresponding phenoxide ions (X-C 6 H 4 -O - ) have also been computed at the same level of theory. The effect of change of substituent position on the energetics of substituted phenols has been analyzed. The correlations of Hammett’s substituent constants with the bond dissociation enthalpies of the O-H bonds of phenols and proton affinities of phenoxide ions have been explored. Keywords: Substituted Phenol, Bond Dissociation Energy, Acidity, DFT. I. Introduction Phenols are widely used as synthetic organic materials and also as antioxidants in living organisms [1]. Phenoxyl radicals are known as important intermediates in many biological and industrial applications [2]. Phenols are of special interest in organic chemistry, since their acid-base equilibria have often been used as reference values in establishing linear free energy relationships [3]. Consequently, much effort has been put to understand the factors governing the O-H bond dissociation energies, BDE(O-H), and acidities of substituted phenols, both in the solution and gas phase [4-11].