Greener Journal of Biological Sciences

Open Access

Greener Journal of  Biological Sciences Vol. 4 (1), pp. 018-032, February 2014.

 © 2011 Greener Journals

Research Paper

Manuscript Number: 011514037

 

A Theoretical Study on Determination of Acidic Dissociation Constants of Penicillamine and Captopril in Water

 

 

Farhoush Kiani, R. Taherinasab, Hasan Tahermansouri and Fardad Koohyar*,

 

 

Department of Chemistry, Faculty of Science, Ayatollah Amoli Branch, Islamic Azad University,

Amol, Iran.

 

 

*Corresponding Author’s Email: f_koohyar@yahoo.com


Abstract:

In this study, pKa values of penicillamine and captopril were determined in aqueous solution. These studies have explored different systems, and different aspects of the computational methods used to estimate pKa. It was found that the calculation of the relative values of pKa for acids of moderate strength is possible by using simple ab initio or density functional theory (DFT) methods. Basis set at B3LYP/6-31+G(d) level of theory was used for calculation. Tomasi’s method was used to analyze the formation of intermolecular hydrogen bonds (IHB) between the existent species and water molecules. Excellent agreement was obtained between the calculated and experimentally determined values.

Keyword: Dissociation Constant, Penicillamine, Captopril, Ab initio method, DFT.


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