On the possibility that cyclodextrins' chiral cavities can be available on AOT n-heptane reverse micelles. A UV-visible and induced circular dichroism study.

摘要: The formation of reverse micelles (RMs) sodium 1,4-bis(2-ethylhexyl)sulfosuccinate (AOT) in n-heptane including two different beta-cyclodextrin (beta-CD) derivatives (hydroxypropyl-beta-CD, hp-beta-CD, and decenyl succinyl-beta-CD, Mod-beta-CD) is reported. Both cyclodextrins can be incorporated into AOT RMs zones within the aggregate, while beta-CD cannot. Using UV-vis induced circular dichroism (ICD) spectroscopy achiral molecular probes (some azo dyes, p-nitroaniline ferrocene), it was possible to determine that Mod-beta-CD located with its cavity at oil side RM interface, for hp-beta-CD inside water pool. Among used, methyl orange (MO) only one which gave ICD signal when dissolved so a detailed study MO behavior homogeneous media also performed compare microheterogeneous media. solvatochromic dye depends not on polarity but other specific solvent properties. A Kamlet-Taft analysis shows absorption spectrum shifts longer wavelength an increase polarity-polarizability (pi*) hydrogen donor ability (alpha) medium. appears almost 3 times more sensitive pi* parameter than alpha parameter. In addition, from spectral changes concentration, association equilibrium constants pure (K11W) (K11RM) were computed. results show K11W 10 larger value RMs. latter explained considering resides anchored interface through bond interaction hydration bound water. This first time cyclodextrin chiral available guest organic medium such as RMs; therefore, we have created potentially powerful nanoreactor confined regions same aggregate: polar core hydrophobic cyclodextrin.