Alternated π‐conjugated polymers based on a 1,2‐diiminocyclohexane chiral unit for nitroaromatics sensing

Abstract

The detection of 2,4‐dinitrotoluene (DNT) by fluorescence quenching of a new class of polyimines consisting in π‐conjugated segments regularly alternated with chiral C2 symmetry units has been studied for solutions and thin films. Their photophysical properties and their sensitivity towards DNT detection has been compared to those of a small model molecule incorporating the same π‐conjugated segment. In solution, all the compounds exhibit the same photo‐physical properties and sensitivity towards DNT detection. In contrast, for thin films, better performances are observed in static conditions for this new class of polyimines compared to the small model molecule. It seems that C2 symmetry units prevent from the stacking of the π‐conjugated segments and provide in addition to high fluorescence signal an improved diffusion of the analyte inside the films. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4141–4149, 2009

Supramolecular Luminescent Sensors

“…Many conjugated polymers rely on π–π stacking between the aromatic analytes and the conjugated backbone of the polymer to enable close-range interactions and drive effective sensing . These interactions have been used successfully for the detection of TNT and related nitroaromatics, , polycyclic aromatic hydrocarbons, and nucleic acids …”

“…1572 Many conjugated polymers rely on π−π stacking between the aromatic analytes and the conjugated backbone of the polymer to enable close-range interactions and drive effective sensing. 1573 These interactions have been used successfully for the detection of TNT and related nitroaromatics, 1574,1575 polycyclic aromatic hydrocarbons, 796 and nucleic acids. 1576 While methods based on aromatic ring association generally work well, such methods are inherently limited to analytes that contain aromatic moieties capable of interacting with the aromatic polymer backbone, which precludes large classes of nonaromatic analytes (i.e., nonaromatic explosives and pesticides) 1577 from participating in such interactions.…”

Detection and Distinction of DNT and TNT with a Fluorescent Conjugated Polymer Using the Microwave Conductivity Technique

“…Much faster and efficient quenching was seen in the presence of DNT than that of TNT. This could be explained by considering the vapor pressures, which is about 18 times higher for DNT (144.36 × 10 –6 mmHg at 25 °C) than that of TNT (8.02 × 10 –6 mmHg at 25 °C) . About 40% quenching was observed during the initial 5 min for DNT, whereas only 15% quenching was observed for TNT during the same time.…”

One pot synthesis of fluorescent π-conjugated materials: immobilization of phenylene–ethynylene polyelectrolytes in silica confined ionogels

“…Solid state thin films allow the detection of TNT vapours as well as a common contaminant in land mines, 2,4-dinitrotoluene (DNT), which has a higher vapour pressure than TNT. 16,27 Therefore, the use of ionogels as disposable sensing devices was explored. Indeed, ionogels combined the pre-concentration ability of IL with the silica transparency, which will make light based detection possible.…”