Evidence of higher complexes between cucurbit[7]uril and cationic surfactants.

Departamento Química Física, Centro Singular de Investigación en Química Biológica y Materiales Moleculares (CIQUS), Universidad de Santiago, 15782 Santiago, Spain.
Chemistry - A European Journal (Impact Factor: 5.93). 05/2012; 18(25):7931-40. DOI: 10.1002/chem.201103049
Source: PubMed

ABSTRACT The host-guest assembly of CB7 with a series of alkyl(trimethyl)ammonium (C(n)TA(+)) surfactants of different chain lengths (n=6-18) has been studied. The complexation behaviour was investigated by NMR spectroscopy, isothermal titration calorimetry and kinetics measurements. The combined results of these techniques provided evidence for the formation of 1:1 inclusion and 2:1 external complexes in the cases of C(n)TA(+) with n=12-18. The binding constants for the 1:1 complexes are independent of the alkyl chain length of the surfactant, whereas a relationship between K(2:1) and the chain length of the surfactant was found for the 2:1 complexes.

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