摘要:
The photophysical, electrochemical and photoprototropic behaviors of diphenylamine (DPA) in aqueous beta-cyclodextrin (beta-CD) solution have been investigated using absorption spectroscopy and cyclic voltammetric techniques. Absorption of the neutral and cationic form of DPA is enhanced clue to the formation of a 1:1 complex with beta-CD. The formation of this complex has been confirmed by Benesi-Hildebrand plot and docking studies by RasMol tool methods. The solid complex of beta-CD with DPA is investigated by FT-IR, XRD and AFM methods. The thermodynamic parameters (Delta G, Delta H and Delta S) of inclusion process are also determined. The pK(a) values of neutral-monocation equilibria have been determined with absorption (conjugate acid-base) titrations. A mechanism is proposed to explain the inclusion process. (C) 2011 Elsevier B.V. All rights reserved.