Acta Phys. -Chim. Sin. ›› 2013, Vol. 29 ›› Issue (03): 508-515.doi: 10.3866/PKU.WHXB201212071

• THEORETICAL AND COMPUTATIONAL CHEMISTRY • Previous Articles     Next Articles

Molecular Acidity of Singly and Doubly Substituted Phenols: Predictions from Density Functional Reactivity Theory and Hammett Constants

LIU Liang-Hong1, ZHANG Peng-Fei2, HUANG Ying1   

  1. 1 School of Pharmacy, Hunan University of Chinese Medicine Changsha Hunan 410208, P. R. China;
    2 Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan 410008, P. R. China
  • Received:2012-10-11 Revised:2012-12-07 Published:2013-02-25
  • Supported by:

    HUANG Ying was supported by the Natural Science Foundation of Hunan Province, China (11JJ5065), Hunan College Student Research Study, Innovative Experiments, China (Xiang Jiao Tong [2011] 272), and “Twelfth Five-Year” Key Discipline of Hunan University of Chinese Medicine- Pharmaceutical Analysis Science, China; ZHANG Peng-Fei was supported by the Funds from the Major New Drug Discovery Science and Technology, China (2012ZX09303013-06), National Natural Science Foundation of China (81272609), and Public Health Department of Hunan Scientific Research Foundation, China (B2010-004); LIU Liang-Hong was supported by the 2012 Innovation Program of Hunan University of Chinese Medicine for Postgraduate Students, China (2012cx07).

Abstract:

Accurate prediction of molecular acidity with ab initio and density functional theory approaches is of great interest, but remains a challenging task. Density functional reactivity theory (DFRT) with quantum descriptors, such as molecular electrostatic potential and valence natural atomic orbital energies, has recently been developed and used for this purpose. Our previous study of substituted benzoic acids revealed a novel approach to quantitatively predict molecular acidity using the Hammett constant, which gave the same prediction accuracy as that of DFRT. In this work, we applied these two approaches to singly and doubly substituted phenol systems, a total of 83 molecules, confirming their effectiveness and robustness. High accuracy was obtained using both approaches, with the DFRT approach achieving slightly higher accuracy than the Hammett approach in general. These results shed further light on the molecular features governing physiochemical properties such as acidity and basicity, both locally on the atomic level and globally on the functional group or molecular level. Our present results confirm the validity of the sum rule of Hammett constants for doubly and multiply substituted compounds.

Key words: Molecular acidity, Density functional reactivity theory, Hammett constant, Molecular electrostatic potential, Natural atomic orbital, Phenol

MSC2000: 

  • O641