N-alkylation briefly constructs tunable multifunctional sensor materials: Multianalyte detection and reversible adsorption

Chu-Ming Pang,Xi-Ying Cao,Ying Xiao,Shi-He Luo,Qi Chen,Yong-Jun Zhou,Zhao-Yang Wang

doi:10.1016/j.isci.2021.103126

Chu-Ming Pang, Xi-Ying Cao + Show 5 more

Open Access

https://doi.org/10.1016/j.isci.2021.103126

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Abstract

SummaryA series of N-alkyl-substituted polybenzimidazoles (SPBIs), synthesized by simple condensation and N-alkylation, act as functional materials with tunable microstructures and sensing performance. For their controllable morphologies, the formation of nano-/microspheres is observed at the n(RBr)/n(PBI) feed ratio of 5:1. Products with different degrees of alkylation can recognize metal ions and nitroaromatic compounds (NACs). For example, SPBI-c, obtained at the feed ratio of 1:1, can selectively detect Cu2+, Fe3+, and NACs. By contrast, SPBI-a, obtained at the feed ratio of 0.1:1, can exclusively detect Cu2+ with high sensitivity. Their sensing mechanisms have been studied by FT-IR spectroscopy, SEM, XPS, and DFT calculations. Interestingly, the SPBIs can adsorb Cu2+ in solution and show good recyclability. These results demonstrate that polymeric materials with both sensing and adsorption applications can be realized by regulating the alkylation extent of the main chain, thus providing a new approach for the facile synthesis of multifunctional materials.

Highlights

In 1H NMR spectrum of PBI, the chemical shifts at 7.41–7.48, 7.51–7.61, and 7.65–7.82 ppm were assigned to aromatic hydrogens (Ha, Hb, and Hc) in the repeating unit, and that at 12.35 ppm was assigned to -NH- (Hd) in the benzimidazole ring
Its solubility was improved via N-alkylation, and a series of substituted polybenzimidazoles (SPBIs) were developed for the first time as colorimetric and ratiometric sensing materials
The morphology of SPBI could be adjusted, and a tendency toward nano-/microsphere formation was observed with increased alkylation

Summary

SUMMARY

A series of N-alkyl-substituted polybenzimidazoles (SPBIs), synthesized by simple condensation and N-alkylation, act as functional materials with tunable microstructures and sensing performance. For their controllable morphologies, the formation of nano-/microspheres is observed at the n(RBr)/n(PBI) feed ratio of 5:1. SPBI-a, obtained at the feed ratio of 0.1:1, can exclusively detect Cu2+ with high sensitivity Their sensing mechanisms have been studied by FT-IR spectroscopy, SEM, XPS, and DFT calculations. The SPBIs can adsorb Cu2+ in solution and show good recyclability These results demonstrate that polymeric materials with both sensing and adsorption applications can be realized by regulating the alkylation extent of the main chain, providing a new approach for the facile synthesis of multifunctional materials

INTRODUCTION

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Conclusions