Investigation of the inclusion processes of N-acetyl-4-aminophenol with Me-β-cyclodextrin: A computational study

The binding of the N-acetyl-4-aminophenol (NAPAP) with Me-β-CD was investigated using semi-empirical and ONIOM2 methods. Two modes of complexation were considered for studying such complex. In A complex the OH group of the guest was pointed toward smaller rim of Me-β-CD, while in B complex the OH group was directed to the wider rim. The semi-empirical results gives that B model is more preferred than A one. Also, the ONIOM2 calculations give preference to B model. The geometrical analysis of the inclusion complexes shows that both NAPAP and Me-β-CD were deformed to increase mutual interactions. Finally, natural bond orbital (NBO) analysis reveals that Van Der Waals interactions are the main driving force of formation of inclusion complex.