Guang pu xue yu guang pu fen xi = Guang pu 2006-12-01

[Study on supramolecular complexes of cyclodextrins and fenoxaprop-p-ethyl by UV spectra].

An-ping Zhang, Fan Luo, Wei-ping Liu

Index: Guang Pu Xue Yu Guang Pu Fen Xi 26(12) , 2298-301, (2006)

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Abstract

The supramolecular complexes of fenoxaprop-p-ethyl and various cyclodextrins (beta-CD, HP-beta-CD, RAMEB) were studied by UV spectra technique. The results showed that all cyclodextrins could form 1:1 inclusion complexes with fenoxaprop-p-ethyl in ethanol-water (the volume ratio of ethanol to water was 1 : 4), and the binding constants of the three types of cyclodextrins toward fenoxaprop-p-ethyl were in the order of KRAEB>>KHP-beta-CD>Kbeta-CD. Between 298. 15 and 318. 15 K, the binding constants decreased with temperature increasing. The Gibbs free energy deltaG, enthalpy change deltaH, and entropy change deltaS determined were all negative, suggesting that the inclusion complexation is exothermic and can spontaneously occur by the balance of enthalpy driving and entropy opposing.