Calculation of Acidity Constants of Some Substituted Thiazole Derivatives Using DFT and UV Spectroscopic Methods

The acidity constants of the compounds, including five-membered heterocyclic (pyrrole, thiophene, furan or thiazole) ring systems were determined at 25oC in aqueous solitions, applying UV-Vis spectroscopic method that uses absorbance diagrams,. In order to explain the pKa values obtained, also the molecule conformations of the bases and their corresponding conjugate acids were investigated, applying density functional theory methods. Basis set at the B3LYP/ 6-31 G(d) level of theory was used for calculations. The results obtained from the calculations were compared with the experimental findings. It seems that high coefficient of correlation for the calculation in determination of acidity constants were observed.