Synthesis and photophysical properties of vice-like 1,8-naphthalimide fluorescent sensor for sensitive detection of Mn2+ and Zn2+

Building fluorescence sensors with intelligent performance on detecting target substrate in our living environment is of great significance. Two 1,8-naphthalimide fluorescence sensors with vice like phthalic acid recognition groups (NAC1, NAC2) were designed and synthesized via a facile method. The photophysical properties of the two compounds were investigated and compared. The research on structure-performance difference showed that NAC2, containing a n-dodecylamino group at the 4-position of the 1,8-naphthalimide moiety, had better fluorescence turn-off performance to Mn2+ and Zn2+. DFT calculations were applied to verify the results. NAC2 can detect the two kinds of metal ions within 1 min, and the detection limit was respectively determined to be 0.040 mg/L (for Mn2+), 0.085 mg/L (for Zn2+). NAC2 was also applied in the practical sample analysis, indicating that it is a potential visualization tool in environmental monitoring.

Automated summary

Two fluorescence sensors with phthalic acid recognition groups were designed and synthesized, and it was found that NAC2 exhibited better performance in detecting Mn2+ and Zn2+. NAC2 also showed potential in practical sample analysis.