Ultrasensitive recognition performance of a folded π-based 1,8-naphthalimide-phthalocyanine fluorescence sensor

• Published in: Dyes and pigments Vol. 218; p. 111496
• Main Authors: Hu, Liu, Han, Huayu, Xu, Zihan, Xie, Kongliang, Song, Kaili, Hou, Aiqin
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2023
• Subjects: 1,8-Naphthalimide; Fluorescence recognition; Level-by-level linkage; Zinc(II) phthalocyanine; π-π interaction; Fluorescence recognition; Zinc(II) phthalocyanine; 1,8-Naphthalimide; Level-by-level linkage; π-π interaction
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2023.111496

Designing ultrasensitive and smart molecules as molecular switches is highly valued in molecular recognition. In this work, a folded π-based molecular switch (NAPC) containing 1,8-naphthalimide and zinc(II) phthalocyanine functional modules was synthesized via cyclo tetramerization of four synthesized 1,8-naphthalimide sensors (NA). The photophysical properties of the folded molecular switch were investigated. This peripherally 1,8-naphthalimide substituted zinc(II) phthalocyanine possessed superior sensitivity in near-infrared “off-on” detection of Al3+, Fe3+, and Cr3+ compared with NA, and the detection limits were calculated to be 0.077 μmol/L for Al3+, 0.073 μmol/L for Fe3+ and 0.067 μmol/L for Cr3+, which were far less than that of NA. Due to the sensitive detection of Fe3+, NAPC was also applied in detecting NO2−. The ultrasensitive recognition mechanism of NAPC was determined to be the level-by-level linkage in the molecule in which the photo-induced electron transfer process in 1,8-naphthalimide sensor module was inhibited by complexing with metal ions first and then caused the inhibition of π-π stacking between two modules. This new folded molecule with a cascade linkage effect has the potential as an excellent fluorescence switch that could be applied in molecular recognition and environmental management. •The folded π-based molecule showed a new response mechanism.•Level-by-level linkage strategy were employed to improve sensitivity.•The molecule NAPC was employed in trace M3+ and NO2− analysis.