A Molecular chameleon: Fluorometric to Pb2+, Fluorescent Ratiometric to Hg2+ and Colorimetric to Ag+ ions

Abstract A molecular chameleon, having D-π-A architecture with phenothiazine donor and rhodanine-3-acetic acid acceptor (PRAA) was synthesized and demonstrated its use as a fluorescent sensor to toxic metals ions. PRAA is highly selective and sensitive to Ag+, Hg2+ and Pb2+ ions and its selectivity can be tuned by solvent polarity. The chameleonic behavior is attributed to the intramolecular charge transfer and variation in the electron density at the ligand atom as a function of solvent polarity. The mechanism of binding and the stoichiometry of interaction is established by experimental and theoretical methods. How PRAA can be used as a probe in aqueous solutions for the detection of Ag+ and Hg2+ ions by using an anionic surfactant medium is convincingly established.