Density functional study of inclusion complex of Albendazole/cucurbit [7]uril: Structure, electronic properties, NBO, GIAO and TD-DFT analysis

In the present work, we investigate theoretically, the structure and electronic properties of inclusion complex of cucurbit [7]uril(Q[7]) with Albendazole (ABZ) using DFT calculations. Two modes of complexation were taken into consideration and the effect of solvent is explicitly taken into account. The results obtained with B3LYP/6-31G (d) method clearly indicate that the complexes formed are energetically favored with or without solvent. Cl complex (Albendazole entering the cavity of 0[7] by propyl and aromatic groups) is found more favored than C2 complex (Albendazole entering the cavity of Q[7] by carbamate group). H-1 nuclear magnetic resonance (NMR) was calculated by the Gauge-Including Atomic Orbital method and compared with available experimental data. Finally, TD-DFT calculations of visible spectra were analyzed and discussed. The theoretical calculation agrees well with that obtained from experimental data. (C) 2015 The Authors. Published by Elsevier B.V.