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

A rhodamine-based Hg²⁺-selective fluorescent probe in aqueous solution

Minglei Zhao, Xiao-Feng Yang, Shenfeng He, and Liping Wang

Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Institute of Analytical Science, Department of Chemistry, Northwest University, Xi’an, 710069, China

E-mail: xfyang@nwu.edu.cn

Received: 13 June 2008  Revised: 16 September 2008  Accepted: 29 September 2008

Abstract: A new rhodamine-based Hg²⁺-selective fluorescent probe (I) was designed and synthesized. Compound I displays excellent selective and sensitive response to Hg²⁺ over other transition metal ions in neutral aqueous solutions. I itself is a colorless, nonfluorescent compound. Upon addition of Hg²⁺ to its solution, the thiosemicarbazide moiety of I undergoes an irreversible desulfurization reaction to form the corresponding 1,3,4-oxadiazole (II), a colorful and fluorescent product, causing instantaneous development of visible color and strong fluorescence emission. Based on this mechanism, a fluorogenic probe for Hg²⁺ was developed. The fluorescence increases linearly with the Hg²⁺ concentration up to 0.8 μmol L⁻¹ with the detection limit of 9.4 nmol L⁻ (3σ).

Keywords: mercury ion - probe - rhodamine B - fluorimetry

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-009-0016-8

Chemical Papers 63 (3) 261–267 (2009)