title: Ion recognition at the interface of self-assembled monolayers (SAMs) of bis-thioctic ester derivatives of oligo(ethyleneglycols).
abstract: Self-assembled monolayers (SAMs) of bis-thioctic ester derivatives of oligoethylene glycols were prepared. When the number of (-CH2-CH2-O-)n units in these podands was either five or six, the corresponding SAMs showed ion binding properties and selectivities similar to those exhibited by 15-crown-5 or 18-crown-6 in aqueous solution, respectively. Impedance data for the SAMs as a function of metal ion concentrations were fitted by using a Langmuir isotherm to determine the association constants (Ka) with the different ions. The SAM derived from the n = 5 compound is selective for Na+ while that with n = 6 is selective for K+. Results presented here confirm the formation of ion recognition domains during self-assembly of acyclic polyethylene glycol derivatives on gold surfaces; this suggests that surface-confined pseudocrown ether structures are formed.
authors.affiliation: Department of Chemistry, University of Miami, Coral Gables, FL 33124-0431, USA. echegoyen@miami.edu
authors.forename: K
authors.initials: K
authors.lastname: Bandyopadhyay
authors.forename: S G
authors.initials: SG
authors.lastname: Liu
authors.forename: H
authors.initials: H
authors.lastname: Liu
authors.forename: L
authors.initials: L
authors.lastname: Echegoyen