Synthesis of Thiosemicarbazone Derivatives of Benzo-15-crown-5 and Their Anion Recognition Properties.

A series of thiosemicarbazone derivatives of benzo-15-crown-5 were synthesized efficiently at room temperature using hydrogenchloride acid (HCl) as catalyst. Their anion recognition properties of a, b and c were studied, the result show they exhibit highly selective binding and sensing of F-, MeCO2- and n-C3H7CO2- in CH3CN (F- > n-C3H7CO2- > MeCO2- > > Cl-, Br- and I-). Especially receptor c shows different UV-Vis spectrum of F- from MeCO2-and C3H7CO2-, in addition to the color of the solution change from colorless to yellow upon the addition of F-, these two points make it suitable to be used as colorimetric anion sensor to identify fluoride anion from other halide anions and carboxylate anions by naked-eye. The connection between receptor and anion is by hydrogen bonding interactions, the binding ratio is 1:1, which have been confirmed by UV-vis inspection spectra in CH3CN and 1HMR in DMSO-d6. [ABSTRACT FROM AUTHOR]