Nopinone-based AIE-active dual-functional fluorescent chemosensor for Hg2+ and Cu2+ and its environmental and biological applications

Abstract

A highly sensitive AIE fluorescent chemosensor, N′-((4′-(6,6-dimethyl-4,5,6,7-tetrahydro-1H-5,7-methanoindazol-3-yl)-[1,1′-biphenyl]-4-yl)methylene)picolinohydrazide (PBPHS), for the detection of Hg²⁺ and Cu²⁺ ions in near 100% aqueous solution was developed based on the renewable β-pinene derivative nopinone. The probe PBPHS was designed and synthesized via a four reaction steps, including condensation, cyclization, Suzuki coupling reaction, and Schiff-base reaction. PBPHS could recognize Hg²⁺ and Cu²⁺ over other competitive metal ions via specific complexation ability towards them. The detection limits of PBPHS for Hg²⁺ and Cu²⁺ were 15 nM and 17 nM, respectively. The fluorescent probe PBPHS could also be utilized to detect S²⁻ and Hg²⁺/Cu²⁺ reversibly for five cycle. Moreover, the different binding mechanisms of PBPHS with Hg²⁺ and Cu²⁺ were confirmed by HRMS analysis, ¹H NMR titration, DFT calculation, and molecular logic gate. Furthermore, the probe PBPHS was applied for the analysis of real water and soil samples and living HeLa cells and zebrafish bioimaging.