Abstract:A C -symmetric triphenylbenzene based photoluminescent compound, 1,3,5-tris(4'-(N-methylamino)phenyl) benzene ([NHMe]TAPB), has been synthesized by mono-N-methylation of 1,3,5-tris(4'-aminophenyl) benzene (TAPB) and structurally characterized. [NHMe]TAPB acts as a selective fluorescent sensor for picric acid (PA) with a detection limit as low as 2.25 ppm at a signal to noise ratio of 3. Other related analytes (i.e. TNT, DNT and DNB) show very little effect on the fluorescence intensity of [NHMe]TAPB. The selec… Show more
“…Also, instead of PET mechanism operative in case of probe 10a, here proton transfer is the actual quenching mechanism. The quenching efficiency of 10b 42 was in between probes 10a and 10c and was in order of basicity of amine nitrogen. The emission spectrum of 10b showed 85% quenching of the emission maxima with 20 equivalents of PA with a detection limit of 9.82 μM.…”
Section: Protonation Of Amine Based Fluorescent Probes For Picric Acidmentioning
Abstract. The picric acid due to its low pKa value possesses distinct physico-chemical features among all other nitro aromatic derivatives to design fluorescent probes for its’ sensitive and selective detection.The...
“…Also, instead of PET mechanism operative in case of probe 10a, here proton transfer is the actual quenching mechanism. The quenching efficiency of 10b 42 was in between probes 10a and 10c and was in order of basicity of amine nitrogen. The emission spectrum of 10b showed 85% quenching of the emission maxima with 20 equivalents of PA with a detection limit of 9.82 μM.…”
Section: Protonation Of Amine Based Fluorescent Probes For Picric Acidmentioning
Abstract. The picric acid due to its low pKa value possesses distinct physico-chemical features among all other nitro aromatic derivatives to design fluorescent probes for its’ sensitive and selective detection.The...
“…The fully N-methyl substituted uorophore 3 has been synthesized by the reaction of 1 with excess methyl iodide in basic medium. 42 Fluorophores 2 and 3 do not form the supramolecular structures, as conrmed from their single crystal structures (Scheme 1). It is important to note that the substitution of N-H groups with N-methyl causes a sizeable red-shi to the absorption and photoluminescence bands of 1 (Fig.…”
Rich and diverse chemistry of 1,3,5-triphenylbenzene is discussed with emphasis on fluorescence based chemo-sensors, apart from a discussion on its use in building a number of supramolecular assemblies and fluorescent covalent-organic-frameworks.
“…There are numerous small molecule sensors as well to detect PA with low LOD. [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] Zinc oxide nanomaterials and fluorescent quantum dots were also helpful in PA detection. [57,58] The fluorescent outputs due to the sensing mechanisms were effectively used to prepare logic based devices in some cases.…”
Picric acid (PA) at low concentration is a serious water pollutant. Alongside, aliphatic amines (AAs) add to the queue to pollute surface water. Plenty of reports are available to sense PA with an ultralow limit of detection (LOD). However, only a handful of works are testified to detect AAs. A new fluorescent donor-acceptor compound has been synthesized with inherent intramolecular charge transfer (ICT) character that enables selective and sensitive colorimetric quantitative detection of PA and AAs with low LODs in nonaqueous as well as aqueous solutions. The synthesized compound is based on a hemicyanine skeleton containing two pyridenylmethylamino groups at the donor and a benzothiazole moiety at the acceptor ends. The detailed mechanisms and reaction dynamics are explained spectroscopically along with computational support. The fluorescence property of the detecting compound changes due to protonation of its pyridinyl centers by PA leading to quenching of fluorescence and subsequently de-protonation by AAs to revive the signal. We have further designed logic circuits from the acquired optical responses by sequential interactions.
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