Host-guest inclusion complex between b-cyclodextrin and paeonol: A theoretical approach

Abstract

Host-guest interactions of b-cyclodextrin (b-CD) with paeonol (PAE) were simulated using semi-empirical PM3 and both ONIOM2 [(B3LYP/6-31G*:PM3), (HF/6-31G*:PM3)] methods. The results obtained with PM3 method clearly indicate that the complexes formed are energetically favored with or without solvent, the model 1 (PAE entering into the cavity of b-CD from its wide side by OCH3 group) is found more favored than the model 2 (PAE entering into the cavity of b-CD from its wide side by COCH3 group). Finally, natural bonding orbital (NBO) analysis was performed based on ONIOM2 optimized complexes to quantify the donor–acceptor interactions between PAE and b-CD.