Synthesis of luminescent covalent-organic polymers for detecting nitroaromatic explosives and small organic molecules

Three porous luminescent covalent--organic polymers (COPs) have been synthesized through self-polycondensation of the monomers of tris(4-bromophenyl)amine, 1,3,5-tris(4-bromophenyl)benzene, and 2,4,6-tris-(4-bromo-phenyl)-[1,3,5]triazine by using Ni-catalyzed Yamamoto reaction. All the COP materials possess not only high Brunauer-Emmett-Teller (BET) specific surface area of about 2000 m(2) g(-1) , high hydrothermal stability, but also graphene-like layer texture. Interestingly, COP-3 and COP-4 show very fast responses and high sensitivity to the nitroaromatic explosives, and also high selectivity for tracing picric acid (PA) and 2,4,6-trinitrotoluene (TNT) at low concentration (<1 ppm). In short, the COPs may be a new kind of material for detecting explosives and small organic molecules.