Synthesis and chemosensory studies of a heterocyclic thiosemicarbazone as a new tributyltin optical chemosensor

Abstract

Thiosemicarbazones are a versatile type of organic compounds which are known by their coordination ability with different types of analytes, due to sulfur and nitrogen heteroatoms presence. Therefore, the functionalization of thiosemicarbazones with heterocyclic moieties can be a promising route to develop new optical chemosensors. Tributyltin (TBT) is an antifouling com-ponent of paints which is acutely toxic to aquatic environments, being quickly absorbed by micro-organisms and causing problems such as imposex. Herein, the synthesis of a novel heterocyclic thiosemicarbazone, functionalized with a quinoline moiety is reported to assess the potential of this recognition moiety for TBT optical chemosensing. A preliminary chemosensory study in acetonitrile solution was performed showing that 50 equiv-alents of TBT were needed to induce a change of color from colorless to yellow. Spectrophotomet-ric titration was performed to assess the concentration of TBT necessary for a maximum optical signal, revealing that 100 equivalents of TBT were necessary to reach maximum absorbance, alt-hough it was able to respond with a detectable color change to a TBT concentration as low as 10 µM.