A novel urea-based “turn-on” fluorescent sensor for detection of Fe3+/F− ions with high selectivity and sensitivity.

A novel urea-based “turn-on” fluorescent sensor 1,3-bis(4-(tert-butyldimethylsilyloxy)phenyl)urea (TBSU) has been synthesized and its sensing properties are explored. This sensor exhibited highly selective and sensitive detection of Fe 3+ and F − ions in aqueous DMSO solution (DMSO/H 2 O, 95/5, v/v) with a significant fluorescence and absorption enhancement. The 1:1 stoichiometric structure between TBSU and Fe 3+ was adequately supported by Job-plot evaluation, optical titration and FT-IR analysis. The recognition process of the chemosensor TBSU for Fe 3+ is chemically reversible on the addition of CN − anion. The Fe 3+ /F − detection was not affected by the coexistence of other competitive ions. In addition, the detection limit was found to be as low as 5.87 × 10 −8 M for Fe 3+ and 4.84 × 10 −8 M for F − , respectively. Thus, TBSU could be a highly promising fluorescent sensor for the direct determination of Fe 3+ /F − ions in aqueous DMSO medium. [ABSTRACT FROM AUTHOR]