ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Fluoride anion sensing using colorimetric reagents containing binaphthyl moiety and urea binding site

Roman Mikláš, Peter Kasák, Ferdinand Devínsky, and Martin Putala

Department of Chemical Theory of Drugs, Faculty of Pharmacy, Comenius Uviversity, Odbojárov 10, 832 32 Bratislava, Slovakia

E-mail: miklas@fpharm.uniba.sk

Received: 16 January 2009  Revised: 17 June 2009  Accepted: 18 June 2009

Abstract: Four 1,1′-binaphthalene based bis-urea derivatives bearing aryl groups at end-on nitrogen atoms IIIa–d were synthesized as potential sensor molecules. These receptors show characteristic UV-VIS spectral changes on complexation with anions and they exhibit selective recognition of F⁻ over other halide anions. Interaction of a fluoride anion with urea NH groups was confirmed by ¹H NMR data. The presence of an electron-withdrawing nitro group in N′-aryls (receptors IIIa and IIIb) appeared to be necessary for naked-eye colorimetric detection. These receptors show dramatic color change from light-yellow to orange (IIIa) or to orange-red (IIIb) in the presence of guest fluoride anions already at concentrations of 10⁻⁵ mol dm⁻³ of the receptor and host.

Keywords: 1,1′-binaphthalene - binaphthyl - chromogenic anion receptor - urea

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-009-0079-6

Chemical Papers 63 (6) 709–715 (2009)