Study of proton transfer in aniline-HCl-catalyst complexes

The aniline-HCl-A complexes are studied using DFT (B3LYP) method and 6-31+G (d,p) basis set. A is a catalyst molecule such as H2SO4, H2SO3, HCOOH, HNO3, HF, CH3OH, H2O, H2O2, HNO2(b), HNO2(a), NH3, HCOH, HCN, HCl, H2S and PH3. We found that the proton transfer take place in 12 structures in which A = H2SO4, H2SO3, HCOOH, HF, HNO2(a), HNO3, H2O2, H2O, NH3, HNO2(b), HCl, CH3OH and not occurred in another 4 structures with A = HCOH, HCN, H2S and PH3. The interaction energies (Eint) of the complexes are computed and correlation between Eint and the extent of proton transfer is investigated. The atoms in molecules theory (AIM) of Bader is also applied to study the intra-cluster hydrogen bonds in the aniline-HCl-A clusters. Additionally, the influence of phenyl ring on the proton transfer reaction is computed with the complexes structures without the phenyl ring (NH3-HCl-catalyst).