A theoretical study on protonation of some halogen substituted pyridine derivatives.

The geometries of 12 multi-halogenated pyridine derivatives were optimized using theoretical methods. The Hartree-Fock (HF) method with the 6-31G(d) and B3LYP method with 6-31G(d) basis sets were found to be adequate in calculation of absolute acidity constants, pK(a) values. A perfect correlation between the computed and experimentally obtained acidity constants, pK(a) values, was observed.