Host–Guest Complexation of <Emphasis Type="Italic">β</Emphasis>-, <Emphasis Type="Italic">γ</Emphasis>-Cyclodextrin with Alkyl Trimethyl Ammonium Bromides in Aqueous Solution |
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Authors: | Xiu-Kui Qu Lan-Ying Zhu Ling Li Xi-Lian Wei Feng Liu De-Zhi Sun |
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Institution: | (1) Department of Chemistry, Liaocheng University, Wenhua Road, Liaocheng, Shandong, 252059, People’s Republic of China;(2) Department of Biology, Liaocheng University, Wenhua Road, Liaocheng, Shandong, 252059, People’s Republic of China |
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Abstract: | As a continuation of our previous investigation, interactions between cyclodextrin (β-CD), γ-cyclodextrin (γ-CD) and alkyl trimethylammonium bromides in aqueous solutions have been studied with titration calorimetry and 1H NMR at 298.15 K. The results are discussed in terms of the amphiphilic interaction of CD with surfactants and the iceberg
structure formed by water molecules existing around the hydrophobic tail of surfactant molecules. The stoichiometry of the β-CD–surfactant system is 1:1 whereas that of the γ-CD–surfactant system is 1:2. The corresponding formation enthalpy (negative) of the complexes of the two systems decreases
with an increase in the number of carbon atoms (n) in hydrophobic chain of surfactant molecule, C
n
H2n+1, whereas the entropy increases with the enlargement of n. |
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Keywords: | Alkyl trimethylammonium bromides β -Cyclodextrin γ -Cyclodextrin Calorimetry Host– guest complex 1H NMR |
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