Self-assembled structures of N-alkylated bisbenzimidazolyl naphthalene in aqueous media for highly sensitive detection of picric acid

Yan-Cheng Wu; Shi-He Luo; Liang Cao; Kai Jiang; Ling-Yun Wang; Jie-Chun Xie; Zhao-Yang Wang

doi:10.1016/j.aca.2017.04.022

Self-assembled structures of N-alkylated bisbenzimidazolyl naphthalene in aqueous media for highly sensitive detection of picric acid

Anal Chim Acta. 2017 Jul 11:976:74-83. doi: 10.1016/j.aca.2017.04.022. Epub 2017 Apr 26.

Authors

Yan-Cheng Wu¹, Shi-He Luo¹, Liang Cao¹, Kai Jiang¹, Ling-Yun Wang², Jie-Chun Xie¹, Zhao-Yang Wang³

Affiliations

¹ School of Chemistry and Environment, South China Normal University, Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, Guangzhou, 510006, PR China.
² School of Chemistry and Chemical Engineering, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, PR China. Electronic address: lingyun@scut.edu.cn.
³ School of Chemistry and Environment, South China Normal University, Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, Guangzhou, 510006, PR China. Electronic address: wangzy@scnu.edu.cn.

PMID: 28576320
DOI: 10.1016/j.aca.2017.04.022

Abstract

A 2,6-dibenzimidazole-appended naphthalene derivative flanking with two N-alkyl chains (sensor 4) was designed and applied for highly sensitive detection of picric acid (PA) in aqueous media. Driven by the hydrophobicity of alkyl chain and π-π stacking effect of aryl, sensor 4 can undergo self-assembly to form an orderly rod-like structure in H₂O/THF (v/v, 90/10) solution, as shown by the dynamic light scattering (DLS) and scanning electron microscopy (SEM) studies. Sensor 4 shows high selectivity and sensitivity toward PA over other nitroaromatic explosives. DFT calculations and ¹H NMR, the time-correlated single photon counting (TCSPC) experiments confirm that the quenching mechanism is due to both electron and energy transfer from the electron-rich sensor 4 to the electron-deficient PA. Sensor 4 can detect as low as 0.57 ppb PA in aqueous media and 11.46 ag cm^-2 PA by contact mode. Importantly, sensor 4 exhibits low interference against common solvents, metal ions and anions. Thus, it is practically applicable for sensing PA in real environmental samples and vapor phase.

Keywords: Bisbenzimidazolyl naphthalene; Fluorescent sensor; Highly sensitive detection; Picric acid; Self-assembly.