p K a Prediction Using Group Philicity

Chemical Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020, India.
The Journal of Physical Chemistry A (Impact Factor: 2.69). 06/2006; 110(20):6540-4. DOI: 10.1021/jp055849m
Source: PubMed


Acid-base dissociation constants (pK(a) values) are important in understanding the chemical, environmental and toxicological properties of molecules. Though various methods have been developed to predict pK(a) by experimental and theoretical models, prediction of pK(a) is still complicated. Hence, a new approach for predicting pK(a) using the group philicity concept has been attempted. Presence of known functional groups in a molecule is utilized as the most important indicator to predict pK(a). The power of this descriptor in describing pK(a) for the series of carboxylic acids, various substituted phenols, anilines, phosphoric acids, and alcohols is probed. Results reveal that the group electrophilicity is suitable for effectively predicting the pK(a) values.

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    • "Density Functional Theory (DFT) have been widely used to study global reactivity descriptors to understand the relationship between structure, stability and global chemical reactivity.Density functional theory based global reactivity descriptors such as hardness, polarizbility, electronegativity, electrophilicity and local descriptors like fukui function, philicity are found to be useful in explaining the various physicochemical properties. These descriptors are used as powerful tool for stydying chemical processes and reaction mechanism, aromaticity, acidity/basicity, biological activities and toxicities of many molecules [12] [13] [14]. Both Hartree Fock (HF) and DFT methods have been employed to predict global reactivity descriptors of compounds. "

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    ABSTRACT: Conceptual density functional theory provides a method for analyzing the chemical reactivity in terms of different global reactivity descriptors including electrophilicity and their local counterparts like philicity. These concepts’ definitions and various applications that demonstrate their interpretive power are discussed. Global and local electrophilicities are able to account for a wide variety of chemical phenomena.
    No preview · Article · Apr 2009 · Annual Reports Section C"" (Physical Chemistry)"""
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    ABSTRACT: The electrophiliciy index proposed by Parr, Szentpaly, and Liu provides insight into almost every arena of chemistry and encompases information about the structure, properties, stability, reactivity, interactions, bonding, toxicity, and dynamics of many electron systems in ground and excited electronic states. The whole gamut of the conceptual density functional theory lends support toward the electrophilicity index and helps it realize its full potential. As is the case for most of the conceptual DFT-based reactivity/selectivity descriptors, the global and local electrophilicities possess strong interpretive power.
    No preview · Article · Jul 2006 · Chemical Reviews
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