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: K Bandyopadhyay, S G Liu, H Liu, L Echegoyen
• Journal: Chemistry (Weinheim an der Bergstrasse, Germany) (Chemistry) Vol. 6 Issue 23 Pg. 4385-92 (Dec 01 2000) ISSN: 0947-6539 [Print] Germany
• PMID: 11140969 (Publication Type: Journal Article)