title: Structure-Binding Effects: Comparative Binding of 2-Anilino-6-naphthalenesulfonate by a Series of Alkyl- and Hydroxyalkyl-Substituted β-Cyclodextrins.
abstract: Cyclodextrins (CDs) are the most widely used organic hosts for the inclusion of guest molecules. CDs can be readily modified through substitutions of the hydroxyl groups, and these modified CDs can have different host binding properties compared to those of parent CDs. However, only relatively few systematic studies of the effects of chemical substitution on CD binding ability have been reported thus far. In this paper, we report the study of the binding properties of five different analytically pure modified β-cyclodextrin (β-CD) hosts (substituted with alkyl and/or hydroxyalkyl groups) with 2-anilino-6-naphthalenesulfonate (2,6-ANS) as guest. Binding constants for the formation of the inclusion complex between 2,6-ANS and each CD were determined using both fluorescence spectroscopy and capillary electrophoresis. Addition of modified CDs to an aqueous solution of 2,6-ANS resulted in significant enhancement of the fluorescence intensity of 2,6-ANS, as well as a significant spectral blue shift, indicative of inclusion. Inclusion of 2,6-ANS within the CD cavity was confirmed by NMR spectroscopy. Substitution at position 3 decreased the magnitude of the binding constants, while alkyl or hydroxylalkyl substitution of the primary hydroxyl at position 6 increased the magnitude of the binding constant in all cases, in relation with increasing length of the alkyl chain linker. In addition, binding constants decreased with solvent polarity when increasing amounts of methanol were added. Structure-binding correlations for CDs based on these binding constant results are presented and discussed.
authors.affiliation: Normandie Université, COBRA, UMR 6014, FR 3038, INSA Rouen, CNRS, IRCOF , 1 rue Tesnière 76821 Mont-Saint-Aignan, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Favrelle
authors.affiliation: Normandie Université, COBRA, UMR 6014, FR 3038, INSA Rouen, CNRS, IRCOF , 1 rue Tesnière 76821 Mont-Saint-Aignan, France.
authors.forename: Géraldine
authors.initials: G
authors.lastname: Gouhier
authors.affiliation: Normandie Université, COBRA, UMR 6014, FR 3038, INSA Rouen, CNRS, IRCOF , 1 rue Tesnière 76821 Mont-Saint-Aignan, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Guillen
authors.affiliation: Normandie Université, COBRA, UMR 6014, FR 3038, INSA Rouen, CNRS, IRCOF , 1 rue Tesnière 76821 Mont-Saint-Aignan, France.
authors.forename: Claudette
authors.initials: C
authors.lastname: Martin
authors.affiliation: Normandie Université, COBRA, UMR 6014, FR 3038, INSA Rouen, CNRS, IRCOF , 1 rue Tesnière 76821 Mont-Saint-Aignan, France.
authors.forename: Nadine
authors.initials: N
authors.lastname: Mofaddel
authors.affiliation: Normandie Université, Crystal Genesis Unit, SMS, EA 3233, Université de Rouen , 76821 Mont Saint-Aignan Cedex, France.
authors.forename: Samuel
authors.initials: S
authors.lastname: Petit
authors.affiliation: Department of Chemistry, University of Prince Edward Island , Charlottetown, Prince Edward Island CIA 4P3, Canada.
authors.forename: Kara M
authors.initials: KM
authors.lastname: Mundy
authors.affiliation: Department of Chemistry, University of Prince Edward Island , Charlottetown, Prince Edward Island CIA 4P3, Canada.
authors.forename: Spencer P
authors.initials: SP
authors.lastname: Pitre
authors.affiliation: Department of Chemistry, University of Prince Edward Island , Charlottetown, Prince Edward Island CIA 4P3, Canada.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Wagner