Luminescent Conjugated Microporous Polymers for Selective Sensing and Ultrafast Detection of Picric Acid

Luminescent conjugated microporous polymers (CMPs) are one of the important class of porous organic materials that possess a fully pi-conjugated skeleton and high surface area and have been utilized as light-emitting materials. In this work, we have designed and developed three luminescent CMPs based on truxene core (Tx-CMPs) via Suzuki-Miyaura cross-coupling reaction in one step. The flexible aryl linker in Tx-CMPs prevents the possibility of aggregation-caused quenching (ACQ) due to pi-pi stacking of layers and thus offers a high luminescence in the synthesized Tx-CMPs. All Tx-CMPs possess a high BET surface area (S-BET = 788-915 m(2) g(-1)) and excellent thermal stability. Utilizing the fluorescent nature and electron-rich property of the Tx-CMPs, we exploited them as a sensor for the selective and sensitive detection of picric acid (PA) among various nitroaromatic explosives. The Stern-Volmer constant (K-SV) for PA was estimated as 3.97 x 10(4), 7.35 x 10(4), and 2.39 x 10(4) M-1 for Tx-CMP-1, Tx-CMP-2, and Tx-CMP-3, respectively, indicating that PA can quench the fluorescence intensity of Tx-CMP-2 most efficiently. The detection limits of Tx-CMPs toward PA were found in the nanomolar range.