Self-assembly of a quadrangular prismatic covalent cage templated by zinc ions: A selective fluorescent sensor for palladium ions

Herein we report a covalent cage TPE-Zn4 based on a tetraphenylethylene molecule via subcomponent self-assembly, which is templated by zinc ions. TPE-Zn4 features a quadrangular prismatic cage structure, which is characterized by NMR, mass spectrum, and single-crystal X-ray diffractions. TPE-Zn4 emitted or-ange fluorescence (& lambda;em = 620 nm) in DMSO solution under the irradiation of UV light (& lambda;ex = 395 nm) and can be applied as a fluorescence sensor for selectively detecting Pd2+. The fluorescence of TPE-Zn4 was quenched by Pd2+ in DMSO solution, and a very low detection limit of 62.3 nM was achieved. Mechanism studies reveal that the Pd2+ can replace the Zn2 +, and the heavy atom effect and chelation-enhanced quenching effect between the Pd2+ and the cage probably cause the fluorescence quenching.& COPY; 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

In this study, a covalent cage TPE-Zn4 based on a tetraphenylethylene molecule was reported, which was templated by zinc ions via subcomponent self-assembly. TPE-Zn4 exhibited a quadrangular prismatic cage structure characterized by NMR, mass spectrum, and single-crystal X-ray diffractions. TPE-Zn4 emitted orange fluorescence (λem = 620 nm) in DMSO solution under UV light irradiation (λex = 395 nm), and it could be used as a fluorescence sensor for selectively detecting Pd2+. The fluorescence of TPE-Zn4 was quenched by Pd2+ in DMSO solution, achieving a very low detection limit of 62.3 nM. Mechanism studies revealed that the fluorescence quenching was probably caused by the replacement of Zn2+ by Pd2+, as well as the heavy atom effect and chelation-enhanced quenching effect between Pd2+ and the cage.