A route to new colorimetric pH sensors

Abstract

Abstract The detection of target molecules via luminescence changes of appropriate sensors is a powerful tool to determine the presence of analytes qualitatively and quantitatively. Therefore, the exploration of synthetic routes to new sensors is important to facilitate the recognition of a large range of analytes. In this report we describe such a new route to sensors and discuss the behavior of the synthesized sensors in the presence of different analytes. The prepared anthracene derivatives belong to two classes of substances. On the one hand imines were synthesized wherein the isomerization of their inherent carbon nitrogen double bond provides an effective non-radiative relaxation pathway. On the other hand amines were received by reduction of the mentioned imines. Their intramolecular charge transfer (ICT) based sensing mechanism allows the detection of protons in a reversible colorimetric fashion. Furthermore, the addition of zinc cations in the aprotic solvent DCM provides the first example showing that the detection of these colorimetric pH sensors is not limited to protons.