Synthesis and evaluation of new thienyl and bithienyl-bis-indolylmethanes as colorimetric sensors for anions

Abstract

The synthesis and full characterization of new bis-indolylmethanes containing thienyl and bithienyl moieties are reported. The sensor ability of the compounds in the presence of halide ions (F-, Cl-, Br- and I-), NO3-, ClO4-, SO42-, CN- and OH- ions was investigated in acetonitrile. The experimental results indicate that they could act as selective chromogenic-sensing molecules for the most basic anions F-, CN- and OH-, as a well-defined color change from yellow to pink was observed. The interaction constants between compounds 1 and 2 in the presence of F-, CN- and OH- were calculated and increased in the order OH- > F- > CN-.