engleski

The Solvent Influence on the Complexation of Amphiphilic Mannosides with β-cyclodextrin

The solvent influence on the complexation of amphiphilic mannosides, consisting of different non-polar moities, with β-cyclodextrin was explored in a range of temperatures (5 ≤ ϑ/ ºC ≤ 65) by means of microcalorimetry and NMR spectroscopy. The complexation was observed only in strongly hydrogen-bonded solvents (water, formamide, N-methylformamide, and ethylene glycol). The stabilities of complexes were higher in water than in investigated organic solvents, whereby all reactions were enthalpically controlled. A notable temperature dependence of ΔrH○ and ΔrS○ was noticed in water. In contrast, the standard complexation parameters in other investigated solvents exhibited relatively weak temperature dependence. As expected, the complex stability was strongly influenced by compatibilty of the guest and the β-cyclodextrin cavity sizes, as well as the flexibility and structure of the hydrophobic group of investigated mannosides. The carried out investigations provided a deeper insight into the hosting process, demonstrating that solvophobically driven formation of cyclodextrin inclusion complexes is not a water limited phenomenon.

cyclodextrin ; inclusion complexes ; microcalorimetry ; NMR ; solvophobic solvation

Special Issue of Bulletin of the Chemists and Technologists of Bosnia and Herzegovina