Pyrene-based monomer-excimer dual response organosilicon polymer for the selective detection of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP)

The formation or destruction of a pyrene excimer with strong emission change makes it a versatile fluorophore to construct excimer emission-based fluorescence probes for various analyte detection. The distinct difference between monomer and excimer emission combined with efficient excimer formation can provide an excellent chance for the detection of microenvironmental changes. However, previous reported sensors were generally based on monomer-excimer conversion mechanism. The structures of monomers and excimers acting simultaneously as recognition sites is rare. Herein, we report a pyrene-based monomer-excimer dual response fluorescent sensor for the selective detection of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP). Pyrenes connect with cyclotetrasiloxane through a carbon-carbon double bond, and the formed polymer provides an ideal platform for the co-existence of monomers and excimers and exhibits different fluorescence behaviors between the two analytes. The cause of different selectivities was explored via theoretical simulations, and the possible response mechanism was speculated. We believe that the design strategy in this study can provide a new perspective to synthesize excimer-based fluorescent probes. A pyrene-based polymer with the coexistence of a monomer and excimer emission exhibited different fluorescence behaviors between TNT and TNP.