Fluorescent imine-linked covalent organic framework turn off sensor for sensitive Co ions detection.

The development of innovative materials capable of detecting heavy metal ions is a crucial goal in the field of environmental remediation. However, achieving high selectivity for specific metal ions remains a challenge. This study designs a novel imine-based COF via Schiff base condensation for efficient detection of cobalt ions (Co) in environmental samples. The π-conjugation system provides excellent fluorescence properties. The COF contains tertiary amine and imine structures with nitrogen and oxygen atoms, enabling coordination with Co as a Lewis base. This interaction disrupts the conjugated structure, causing fluorescence quenching. The experimental results demonstrate that our proposed method stands out in Co detection, distinguished by its remarkable simplicity, exceptional sensitivity, rapid response time, and easy operability. The novel imine-based COF sensor exhibits high sensitivity (limit of detection = 8.5 × 10 M), excellent selectivity and stability in fluorescence detection, enabling accurate identification of Co in complex environments. This research not only presents an efficient and practical approach for the detection of Co but also offers novel theoretical perspectives on the design and application of imine-based COF. The findings lay a solid foundation for the development of COF-based environmental monitoring technologies.