Preparation, physicochemical analysis and molecular modeling investigation of 2,2′-Bipyridine: β-Cyclodextrin inclusion complex in solution and solid state

Supramolecular interaction between 2,2'-Bipyridine (BPY) and beta-Cyclodextrin (beta-CD) has been investigated in solution and solid state. Non-covalent interaction between BPY and beta-CD was studied in solution using absorption and fluorescence spectroscopy. Inclusion complex of BPY and beta-CD was prepared in solid state by co-precipitation method and it was characterized using Fourier Transform Infra-red spectroscopy (FT-IR), Thermal analysis, Scanning Electron Microscopy (SEM), Powder X-ray diffractometry (XRD) and Atomic Force Microscopy (AFM). Binding constant values and 1:1 stoichiometry of the inclusion complex were calculated using Benesi-Hildebrand plots at 303 K. Using continuous variation method the 1:1 stoichiometry has been confirmed for BPY: beta-CD complex. Thermodynamic parameter, Delta G of inclusion complex formation was determined and the negative value indicated that the inclusion process was an exergonic and spontaneous process. The most probable model of BPY: beta-CD inclusion complex suggested by molecular docking studies was in good agreement with the results obtained by experimental methods. (C) 2015 Elsevier B.V. All rights reserved.