Orientational effect of surface-confined cyclodextrin on the inclusion of bisphenols.
The molecular recognition of various kinds of bisphenols (BPs) and a bisphenol A-polymer conjugate (BPA-polymer) by a self-assembled monolayer (SAM) of thiolated beta-cyclodextrin (CD) on a gold electrode was examined using cyclic voltammetry (CV). Based on the inhibitory effect of BPs on the inclusion of hydroquinone (HQ) as a probe by the surface-confined CD, the association constants (K(assoc)) of BPs with the immobilized beta-CD were estimated. The K(assoc) values for BPs with the SAM of 3-dithiobis(undecanoylamido)-3-deoxy-beta-cyclodextrin (DTUA-beta-CD) were smaller than those in the free beta-CD system reported previously. A similar tendency was obtained when 6-(lipoylamido)-6-deoxy-beta-cyclodextrin (LP-beta-CD) was used in place of DTUA-beta-CD. The K(assoc) values for all the BPs except for bisphenol B with the SAM of LP-beta-CD were always larger than those with the SAM of DTUA-beta-CD, due to a difference in the orientation of the beta-CD moiety in the SAMs. Furthermore, adsorption and desorption processes of the BPA-polymer from the surface-confined beta-CD was followed using local surface plasmon resonance spectroscopy.
Endo
Hiroshi
H
Department of Chemical and Biochemical Engineering, Toyama University, Toyama 930-8555, Japan.
Nakaji-Hirabayashi
Tadashi
T
Morokoshi
Shinta
S
Gemmei-Ide
Makoto
M
Kitano
Hiromi
H
D000577:Amides / Q000737:chemistry; D002942:Circular Dichroism; D003505:Cyclodextrins / Q000737:chemistry*; D004566:Electrodes; D006046:Gold; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry*
D000577:Amides; D003505:Cyclodextrins; D010636:Phenols; D006046:Gold