Recent progress in the development of fluorescent probes for hydrazine.

Hydrazine (N2 H4 ) is an important and commonly used chemical reagent for the preparation of textile dyes, pharmaceuticals, pesticides and so on. Despite its widespread industrial applications, hydrazine is highly toxic and exposure to this chemical can cause many symptoms and severe damage to the liver, kidneys, and central nervous system. As a consequence, many efforts have been devoted to the development of fluorescent probes for the selective sensing and/or imaging of N2 H4 . Although great efforts have been devoted in this area, the large number of important recent studies have not yet been systematically discussed in a review format so far. In this review, we have summarized the recently reported fluorescent N2 H4 probes, which are classified into several categories on the basis of the recognition moieties. Moreover, the sensing mechanism and probes designing strategy are also comprehensively discussed on aspects of the unique chemical characteristics of N2 H4 and the structures and spectral properties of fluorophores.