A poly(carbazole‐alt‐fluorene) π‐conjugated polymer bearing thiophenyl benzimidazole: synthesis, characterization and fluorescence recognition of metal ions and cysteine

Abstract

A novel conjugated polymer PFCZ‐IM containing 2‐(thiophen‐2‐yl)‐1H‐benzo[d]imidazole units was synthesized and characterized. The basic photophysical properties of the polymer and its fluorescence recognition behaviors toward metal ions and amino acids were investigated. In the study of the response of metal ions, PFCZ‐IM had high sensitivity to Fe3+, Ag+ and Cu2+, which significantly quenched the fluorescence of the polymer. The binding of the 2‐(thiophen‐2‐yl)‐1H‐benzo[d]imidazole moiety to Cu2+ was investigated by density functional theory calculation. Interestingly, [PFCZ‐IM‐Cu2+] also exhibited outstanding characteristics of fluorescence ‘turn on’ in the presence of cysteine (Cys), as the interaction between Cu2+ and Cys caused the polymer to dissociate from the complex. In particular, addition of 30 μmol L–1 of Cys can increase the Cu2+‐quenching fluorescence of PFCZ‐IM by 34.8 times with short response time, demonstrating that [PFCZ‐IM‐Cu2+] has tremendous potential in the actual detection of Cys. This polymer is expected to be utilized for dual fluorescence detection of specific metal ions and Cys. © 2021 Society of Industrial Chemistry.

A Poly(carbazole-alt-triazole) with Thiabendazole Side Groups as an “On-Off-On” Fluorescent Probe for Detection of Cu(II) Ion and Cysteine

“…At the same time, considering the importance of the recognition unit, thiabendazole was introduced as the recognition unit into the side chain through the alkylation reaction. Considering the relatively weak coordination ability of imidazole with copper ions, with the addition of cysteine, Cu 2+ can be deprived from the P-Cu 2+ complex, blocking the occurrence of PET mechanism and restoring the uorescence [27]. We expect that PCZBTA-TBZ will provide an important reference for the development and utilization of novel conjugated polymer uorescence sensors.…”

Energy band gap modulation and photoinduced electron transfer fluorescence sensing properties of D–A conjugated polymers containing benzotriazole

“…Introduction of benzimidazole unit into the side chain on CPs with carbazole-fluorene as the main chain, high sensitivity, and selective detection of metal ions were realized. 35,36 However, the main chain unit has no obvious donor-acceptor effect, and the emission wavelength is in the blue light region, which leads to a large overlap between the excitation and emission wavelength. This causes self-absorption, which decreases detection sensitivity.…”

“…Based on PET fluorescence sensing mechanism, polymers with benzimidazole unit as side chain have been reported. Introduction of benzimidazole unit into the side chain on CPs with carbazole‐fluorene as the main chain, high sensitivity, and selective detection of metal ions were realized 35,36 . However, the main chain unit has no obvious donor‐acceptor effect, and the emission wavelength is in the blue light region, which leads to a large overlap between the excitation and emission wavelength.…”