Determination of the pK _a values of some pyridine derivatives by computational methods

In this study, pKa values are determined relying on density functional theory, its related methods such as WB97XD, M062X, B3LYP with 6-31+Gdp and 6-311++Gdp basis sets for three pyridine derivatives, namely isoniazid, nicotinamide and pyridoxine. When investigating the obtained values, the most accurate values are found to be obtained via the WB97XD method with 6-31+Gdp basis set in water phase. The pKa values calculated in the gas phase were not satisfactory enough to compare with the experimental results.