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 novel conjugated polymer PCZBTA-TBZ containing thiabendazole as recognition unit was synthesized via Suzuki coupling reaction, and its structural characterization, spectroscopic analysis and photophysical properties were investigated. In the metal ion response study, the addition of Cu 2+ led to the occurrence of the PET mechanism, which signi cantly quenched the uorescence of the polymer PCZBTA-TBZ with a quenching effect of 98%. According to the density functional theory calculation, compared with other polycarbazoles or other alternative copolymers containing carbazole, with alternating carbazole and triazole enhances the electron mobility and reduces the energy band gap of the polymer. Due to the strong coordination ability between Cu 2+ and Cys, the adding Cys competes the Cu 2+ in the [PCZBTA-TBZ-Cu 2+ ] complex, blocking the occurrence of PET, and the uorescence intensity of PCZBTA-TBZ is restored. The addition of other amino acids caused almost no change. The polymer is expected to be used for dual uorescence detection of speci c metal ions and Cys.

A novel conjugated polymer PCZBTA-TBZ containing thiabendazole as recognition unit was synthesized via Suzuki coupling reaction, and its structural characterization, spectroscopic analysis and photophysical properties were investigated. In the metal ion response study, the addition of Cu2+ led to the occurrence of the PET mechanism, which significantly quenched the fluorescence of the polymer PCZBTA-TBZ with a quenching effect of 98%. According to the density functional theory calculation, compared with other polycarbazoles or other alternative copolymers containing carbazole, with alternating carbazole and triazole enhances the electron mobility and reduces the energy band gap of the polymer. Due to the strong coordination ability between Cu2+ and Cys, the adding Cys competes the Cu2+ in the [PCZBTA-TBZ-Cu2+] complex, blocking the occurrence of PET, and the fluorescence intensity of PCZBTA-TBZ is restored. The addition of other amino acids caused almost no change. The polymer is expected to be used for dual fluorescence detection of specific metal ions and Cys.