Thermodynamic studies of inclusion complex formation between alkylpyridinium chlorides and β-cyclodextrin using conductometric method
- 180 Downloads
Thermodynamics on inclusion complexation of β-cyclodextrin (β-CD) with n-alkylpyridinium chlorides (C n PC, n = 12, 14, 16) were measured by conductivity technique to evaluate the effects of chain length of C n PC and temperature. The data obtained indicate that inclusion complexes S(CD) and S(CD)2 had formed between surfactant and β-CD in aqueous solution. Investigation showed that the K 1 (first equilibrium constant) for S(CD) formation is greater than K 2 (second equilibrium constant) for S(CD)2 formation. It has been found that C12PC forms only the 1:1 complex, while C14PC and C16PC form 1:1 and 1:2 complexes. Thermodynamic parameters of the complexation, i.e. ΔG°, ΔH° and ΔS° have been also calculated. The large values of ΔG° indicate that complexation between surfactant and β-CD is very favorable.
KeywordsInclusion complex Alkylpyridinium chlorides Cyclodextrin Conductometry Thermodynamic parameters
The authors are grateful for the financial support from the Research Councils of Malayer University.
- 2.Bender, M.L., Komiyama, M.: Cyclodextrin Chemistry. Springer-Verlag, Berlin (1978)Google Scholar
- 21.Rafati, A.A., Hashemianzadeh, S.M., Nojini, Z.B.: Quantum chemical study of the host–guest inclusion complexes of the local anaesthetic drugs, procaine hydrochloride and butacaine hydrochloride, with a- and b-cyclodextrins. Monatsh. Chem. 139, 763–771 (2008)Google Scholar
- 29.Liu, Y., Tong, L.H., Huang, S., Tian, B.Z., Inoue, Y., Hakushi, T.: Complexation thermodynamics of bis(crown ether)s. 4. Calorimetric titration of intramolecular sandwich complexation of thallium and sodium ions with bis(15-crown-5)s and bis(12-crown-4)s: enthalpy–entropy compensation. J. Phys. Chem. 94, 2666–2670 (1990)CrossRefGoogle Scholar