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In this study, drastic influence of the intramolecular cation-π interaction on the basicity of selected amines has been considered. The optimized minimum energy geometries of different studied amines and their protonated structures were determined by using DFT calculations at the B3LYP/6-311++G(d,p) level of theory. Geometry optimizations indicate that the most stable structures of protonated amines are stabilized by intramolecular cation-π interaction. The proton affinity (PA) of selected amines is controlled by the strength of intramolecular cation-π interaction of ammonium with aromatic ring. These cation-π interactions strongly influence the basicity of amines. Natural bond orbital (NBO)... 

With the specific target of calculating the pK a values of boronic acids (RB(OH) 2) in aqueous solution we inquired the solute-solvent interactions of these acids and their corresponding conjugate base. Relative pK a values were computed for each boronic acid using methylboronic acid (CH 3B(OH) 2) as a reference. All gas phase computations were performed at (MP2/6-311++G(d,p)//B3LYP/6-31+G(d)) level of theory. Solvation was included in the calculations using the polarized continuum model (PCM) at the HF/6-31G(d,p) level. The geometry optimization of studied structures was performed with DFT computation and the optimized structures were used to carry out Natural Bond Orbital (NBO) analysis....