Analysis of Static and Dynamic Host-Guest Associations of Detergents with Cyclodextrins via Photoluminiscence Methods

Article abstract of DOI:10.1021/ja00371a001

Host-guest inclusion type associations between β- and γ-cyclodextrins (CD) and a series of cationic phosphorescence detergent probes (i.e., trimethylammonium bromide, alkyl = methyl (n=1, BNK-1⁺), pentyl (n=5, BNK-5⁺), and decyl (n=10, BNK-10⁺)) are reported.No evidence for association could be detected for α-CD.The association equilibrium constant (K), the association rate constant (k_f), and the dissociation rate constant (k_b) were evaluated from dynamic phosphorescence decay method by using Co(NH3)6³⁺ as an aqueous-phase phosphorescence quencher.The k_f values are of the order of 10⁷ M^-1 s^-1 and are independent of the detergent structure.However, the magnitudes of k_b and K vary over several orders of magnitude as a function of detergent and host structure.The results are discussed in terms of the importance of dehydration of CD and/or probe as a rate-determining step of inclusion.