Perylene Diimide Appended with 8-Hydroxyquinoline for Ratiometric Detection of Cu2+ Ions and Metal Displacement Driven “Turn on” Cyanide Sensing

Perylene diimide (PDI) 3 and 4 appended with 8-hydroxyquinoline derivatives have been synthesized and their photophysical and spectroscopic properties have been experimentally determined. Moreover, PDIs 3 and 4 show ratiometric behavior to detect Cu2+ colorimetrically with visible color change from coral red to light pink, whereas 3 and 4 show “turn-off” behavior in fluorescence with lowest limit of detection 5 × 10−7 M. The PDI 3 could be further utilized for ratiometric CN− detection colorimetrically and as “turn-on” sensor for CN− detection fluorometrically with lowest limit of detection 8 × 10−6 M. The comparison of spectroscopic properties of PDI 1-4 highlights the importance of linking 8-hydroxyquinoline units on the PDI core at bay position for achieving Cu2+ recognition event into ratiometric signal.