title: Dual Sensing by Simple Heteroditopic Salt Receptors Containing an Anthraquinone Unit.
abstract: We synthesized simple ion pair receptors consisting of a crown ether cation binding site and an anthraquinone-supported thiourea anion binding domain and studied their anion-, cation-, and salt-binding properties using spectroscopic, spectrophotometric, and electrochemical measurements in acetonitrile solution. Apart from carboxylate anions, which cause deprotonation, all the anions tested were found to associate with receptor 1 more strongly in the presence of sodium cations, whereas in the presence of potassium or ammonium cation the anion binding strength was greatly diminished. A homotopic anion receptor 3, lacking a crown ether unit, was unable to bind sodium salt more strongly than tetrabutylammonium salts. Solution and solid-state X-ray measurements revealed that strong sodium coordination with the cation-binding domain is responsible for the salt-binding enhancement. Electrochemical measurements showed that the addition of anions to the receptor 1 pretreated with sodium cations resulted in greater changes in reduction potentials compared to the addition of anions to receptor 1 in the absence of Na(+).
authors.affiliation: Faculty of Chemistry, University of Warsaw , Pasteura 1, PL 02-093 Warsaw, Poland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Karbarz
authors.affiliation: Faculty of Chemistry, University of Warsaw , Pasteura 1, PL 02-093 Warsaw, Poland.
authors.forename: Jan
authors.initials: J
authors.lastname: Romański