Electrochemical detection of electrochemically inactive cations by self-assembled monolayers of crown ethers

S. Flink, Bernard A. Boukamp, Albert van den Berg, F.C.J.M. van Veggel, David Reinhoudt

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Self-assembled monolayers (SAMs) of 2-[(6-mercaptohexyl)oxy]methyl-12-crown-4 (1) and 2-[(6-mercaptohexyl)oxy]methyl-15-crown-5 (2) on gold are able to bind cations reversibly from aqueous solutions. This binding of the electrochemically inactive cations is monitored by cyclic voltammetry and impedance spectroscopy using the redox couple Ru(NH3)62+/3+ as "reporter ion". Gold electrodes modified with 1 detect Na+ even in the presence of a 100-fold excess of K+; SAMs of 2 are K+ selective. As a result of the high surface density of crown ethers, sandwich complexes are formed. Reduced surface concentrations of receptors in mixed monolayers of 2 with heptanethiol prevent the sandwich complexation and decreases the K+/Na+ selectivity of the SAM.
Original languageUndefined
Pages (from-to)4652-4657
JournalJournal of the American Chemical Society
Issue number120
Publication statusPublished - 1998


  • METIS-105940
  • IR-10993

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