Pyrene Based Schiff Bases as Colorimetric and Ratiometric Sensors

Abstract

A Pyrene based Schiff bases probe 3 and 5 has been synthesized and demonstrated to study the photophysical behaviour towards different metals and anions. The probe 3 has been used for selective estimation and colorimetric response of F- ions as compared to other anions in acetonitrile solution and signalled the binding event through formation of new absorption band at 455 and 490 nm and emission band at 470 and 580 nm. In case of Probe 5, showed selectivity towards F- and CN- ions in the presence of other anions and signaled the binding event through formation of new absorption band at 500 and 515 nm and emission band at 525 nm respectively. Addition of metal ions to acetonitrile solution of probe 3 and 5 can result in an obvious colour change (from yellow to reddish-brown) for Fe3+ ions and UV–vis absorption spectral change in a short time. Job`s plots indicated the formation of a (1:1) complex (receptor:anion) with Fe3+ ions in probe 3.