Modeling Molecular Acidity with Electronic Properties and Hammett Constants for Substituted Benzoic Acids

• DOI: 10.1021/jp209540p
• Publication Date: 2011-11-14T18:41:56Z
• Authors: Ying Huang; Lianghong Liu; Wanhui Liu; Shaogang Liu; Shubin Liu
• Keywords: Benzoic acid; Hammett equation

Molecular acidity is an important physiochemical property essential in many fields of molecular studies, but efficient and reliable computational approach to make accurate predictions still missing. In this work, based on our previous studies use gas phase electronic properties such as electrostatic potential valence natural atomic orbitals the acidic atom leaving proton, we demonstrate here that different approaches can be employed tackle problem. To end, employ 196 singly, doubly, triply substituted benzoic acids for study. We show two are possible, one focusing carboxyl group through its localized other substituting groups via Hammett constants their additivity rule. Our present results clearly exhibit with linear models built from singly species, accurately predict pK(a) values doubly species both these approaches. The consistent each agree well experimental data. These intrinsically manifestations same property, valid complementary other.