Recent development of luminescent chemosensors for the recognition of nitroexplosives based on zinc(II) Schiff base complexes

Abstract

In this review, we briefly summarize the key aspects of the synthetic strategies for zinc(II) Schiff base complexes, focusing on their photophysical properties such as the origin of luminescence, intensity, lifetime, and quantum yield. Additionally, we discuss the advantages of using luminescent zinc(II) complex-based sensors, the factors underlying their effectiveness as chemosensors for explosive detection, their mechanisms of action, and future outlooks and concerns. Most of the zinc(II) Schiff base complexes reported to date function as turn-off luminescent chemosensors for nitroexplosives. Some zinc(II) complexes discussed in this review demonstrate very high selectivity and sensitivity, with limits of detection (LOD) in the ppb or nM range for picric acid. Additionally, certain zinc(II) complexes can detect picric acid in the solid state through a visible color change observable to the naked eye under ambient light.