Trace level detection of nitroanilines using a solution processable fluorescent porous organic polymer

Abstract

Fax: +91 (0)755 409 2392; Tel: +91 (0)755 669 2378. †Electronic Supplementary Information (ESI) available: [Details of characterizations of the polymer, molecular structures of the analytes, limits of detection, solid-state contact mode detection of nitroanilines, EPR and computational investigations.]. SeeA solution processable conjugated porous organic polymer (POP) based on tetraphenyl-5,5dioctylcyclopentadiene (TPDC-DB) was employed for nitroaromatics sensing by amplified fluorescence quenching. A comprehensive investigation was carried out using a set of 30 closely related analytes such as nitrophenols, nitrotoluenes, nitroanilines, nitobenzenes, quinones etc. Nitroanilines were found to be the most efficient quenchers in contrast to the extensively studied picric acid, which is unprecedented among POPs. Rigorous spectroscopic investigations including UV-Vis absorption, steady-state and time-resolved fluorescence, electron paramagnetic resonance coupled with computational studies provided new insight into the underlying photophysical phenomenon of fluorescence quenching. The Stern-Volmer plots were analyzed employing sphere of action model. It was observed that the electron-deficient nature of the nitroaromatics is not the sole governing factor responsible for fluorescence quenching. Naked eye detection of nitroanilines by TPDC-DB was also demonstrated. Detection limits for p-nitroaniline were found to be extremely low, 455 ppb in solution and ~ 1.8 ng cm -2 in contact mode. Scheme 1. Fabrication of porous organic polymer TPDC-DB by Sonogashira cross coupling between tetrakis(4-bromophenyl)-5,5dioctylcyclopentadiene and 1,4-diethynylbenzene.

Cerium Coordination Polymer Based Composite Mimicking Peroxidase for Detection of Nitroaniline

“…The adsorption difference versus the nitroaniline concentration is shown in Figure 11b, which shows a linear relationship between the adsorption and the concentration. The low limit for the detected nitroaniline concentration is 3.125 × 10 −4 mg/mL, which is lower than some published results [29] and comparable to other's work [30].…”

The preparation of covalent triazine‐based framework via Friedel‐Crafts reaction of 2,4,6‐trichloro‐1,3,5‐triazine with N,N′‐diphenyl‐N,N′‐di(m‐tolyl)benzidine for capturing and sensing to iodine

“…There are no overlaps between the two spectra, indicating that the mechanism of TDPDB fluorescence sensing to I 2 and PA is the electron transfer rather than energy transfer mechanism (Table S1 and Figure S16). Stern‐Volmer plots, which indicated that the fluoreacence quenching is the combination of static quenching and dynamic quenching (Figure C) …”

Functionalized Truxene Scaffold: A Promising Advanced Organic Material for Digital Era

“…Therefore, the detection of these explosives from soil and water becomes an interesting and challenging problem in the field of environmental chemistry. Among all the reported methods for sensing of explosives materials, the optical sensing method is found to be more sensitive, selective, and portable for the detection of explosives . The higher sensitivity and selectivity of fluorescent conjugated polymers is due to the presence of electron donating moieties, being responsible for enhancing the contact between the electron‐rich polymers and electron‐deficient explosives .…”

“…Among all the reported methods for sensing of explosives materials, the optical sensing method is found to be more sensitive, selective, and portable for the detection of explosives. [100][101][102] The higher sensitivity and selectivity of fluorescent conjugated polymers is due to the presence of electron donating moieties, being responsible for enhancing the contact between the electronrich polymers and electron-deficient explosives. [103,104] The starshaped truxene molecules are efficient building blocks for the construction of electron-rich π-extended-conjugated polymers.…”