Pentiptycene-Derived Fluorescence Turn-Off Polymer Chemosensor for Copper(II) Cation with High Selectivity and Sensitivity

Abstract

Fluorescent conjugated polymers (FCPs) have been explored for selective detection of metal cations with ultra-sensitivity in environmental and biological systems. Herein, a new FCP sensor, tmeda-PPpETE (poly[(pentiptycene ethynylene)-alt-(thienylene ethynylene)] with a N,N,N -trimethylethylenediamino receptor), has been designed and synthesized via Sonogashira cross-coupling reaction with the goal of improving solid state polymer sensor development. The polymer was found to be emissive at λ max~4 59 nm under UV radiation with a quantum yield of 0.119 at room temperature in THF solution. By incorporating diamino receptors and pentiptycene groups into the poly[(phenylene ethynylene)-(thiophene ethynylene)] (PPETE) backbone, the polymer showed an improved turn-off response towards copper(II) cation, with more than 99% quenching in fluorescence emission. It is capable of discriminating copper(II) cation from sixteen common cations, with a detection limit of 16.5 nM (1.04 ppb).

Design and synthesis of triptycene based fluorescent polymer with pendent triazole: Effect of functionality on host–guest interaction

“…Fluorescent polymers are relatively electron rich in nature and these may act as electron donors in presence of electron deficient molecules . On the other hand, picric acid and fullerene C 60 are relatively electron deficient and these may accept electron density from the relatively electron rich polymers.…”

“…In contemporary research, electron rich conjugated fluorescent materials have emerged as one of the promising candidates for chemical sensing due to their high sensitivity towards analytes that are relatively electron deficient . Fluorescence spectroscopy has been used as the analytical tool for use of these fluorescent materials as chemical sensors.…”

“…Fluorescence spectroscopy has been used as the analytical tool for use of these fluorescent materials as chemical sensors. In literature, several such polymeric materials have been reported that may be considered as fluorescent sensors . Polymer‐based sensors have several advantages over small molecule based sensors which include but are not limited to signal amplification (due to presence of more number of sensing units per polymeric unit), facile fabrication of polymer film and higher stability of the polymers.…”

“…In this context, there are reports of triptycene based fluorescent polymers that have demonstrated applications as chemosensors, wherein fluorescence quenching is caused by guest molecules due to their penetration in the voids generated by the IFV (internal free volume) of triptycene motifs. These host–guest complexation experiments were investigated using fluorescence spectroscopy …”

Sensors from Electrospun Nanostructures

“…A fluorescence sensor based on a pentiptycene conjugated polymer was used for Copper (II) cation detection, with high selectivity and sensitivity [78].…”