Fluorene – Triazine Conjugated Porous Organic Polymer Framework for Superamplified Sensing of Nitroaromatic Explosives

摘要： A porous organic polymer with fluorene and triazine units (PTF), was synthesised through a simple cost effective method. The material was well characterised by FT-IR, solid state 13C NMR and X-ray photoelectron spectroscopic studies. Absorption spectrum indicated the electronic coupling between the two units in the polymer backbone. Experiments proved high thermal and chemical stability, and porous nature of the material. Luminescence of PTF was quenched, on the addition of ppb level concentration of nitroaromatic compounds. This was attributed to the photo induced electron transfer from the electron rich polymer backbone to the electron deficient nitro aromatic compounds. The observed superamplification effect in the fluorescence quenching was studied extensively by a series of ground state absorption, steady state and time resolved fluorescence experiments. Finally, the superamplified quenching was successfully assigned to static quenching by quenching sphere of action model. High value of static quenching constant of the order of 3.9 × 103 M-1, for picric acid combined with detection limit as low as 89 ppb envisages PTF as an effective chemosensor for nitroaromatic explosives.