Quantum Mechanical Studies on the π-π Stacking Interactions of Aniline and Water-assisted Aniline in Gas and Aqueous Phases

The quantum mechanical study of weak interactions such as π-π stackinginteractionsof aromatic molecules has been an important aspect, since high level methods have limitations for application to large molecules. The differences in the stacking energies of various aromatic molecular structures are found quite significant.It has also been found significant for identifying the most favoured stacked modelsof aniline and some ofthe substituted anilinemolecules. There observeda remarkable change in interaction energies for both gas and solvent phasesfor the same stacked models. The effect of basis set in the stacking energies of the second order Møller-Plesset perturbation method(MP2)calculations is very small. The moderately accurate calculations, MP2level of theorieswere found feasible for mostof the simplearomatic systems such as benzene, pyridine, anilineetc. In our study,the investigation was on the π-π stacking interaction energies for stacked models ofanilineandwater-assisted aniline systemsboth in gas and aqueous phases.