Cyclodextrin-based [2]pseudorotaxane formation studied by probe displacement assay

摘要

In the present manuscript, we use a guest displacement assay as a methodological tool to study the [2]pseudorotaxane formation between a bolaform surfactant and -cyclodextrin. The displacement assay has several advantages in comparison with the most used NMR spectroscopy because its larger availability and mainly the possibility to study inclusion processes taking place in the millisecond time scale. Application to rotaxane formation between bolaform surfactants, B-10 or B-12, and -CD allows us to obtain the activation parameters for this reaction. Activation enthalpy for the dissociation step is larger, more positive, than for the inclusion one according to the [2]pseudorotaxane formation being an exothermic process. Activation entropy is negative reflecting the loss of movement freedom on going from reactants to the transition state with the dissociation step being more negative than the inclusion one. Copyright (c) 2015 John Wiley & Sons, Ltd.