Abstract:

 Based on the crystal structural data, intramolecular hydrogen bonding (intra-HB) geometries and atomic partial charges at STO-3G level in 59 ortho-substituted phenols were calculated. As shown by the results, the bond lengths between the phenolic oxygen and its attached carbon atoms in benzene ring, the atomic partial charges of the phenolic hydrogen atoms and the endocyclic angles at the phenolic groups, all have approximate linear correlation with the acidic constants of the substituted phenols. There is a significant difference between five- and six-membered intra-HB rings. In most of six-membered rings, intra-HB are strengthened by the resonance, by which the characterictics of intra-GB in phenols could well be rationized.

Key words: Phenols, Resonance-assisted hydrogen bonding, Intramolecular hydrogen bonding, Crystal chemistry