A novel carbazole-based ratiometric fluorescent sensor for Zn recognition through excimer formation and application of the resultant complex for colorimetric recognition of oxalate through IDAs

A new carbazole-based Zn²⁺ selective fluorescent sensor L has been developed. In CH₃CN/H₂O (1:1, v/v, HEPES 10 mM, pH=7.4) solution, L displays selective and ratiometric responses to Zn²⁺ through excimer formation. The Zn²⁺ recognition process has good anti-interference ability over other metal ions. The dinuclear complex Zn₂L₂ was further used as a receptor for oxalate. Through constructing a chemosensing ensemble with chromeazurol S, colorimetric recognition of oxalate in water solution was achieved via indicator displacement assays. The oxalate recognition process exhibits obvious color changes from blue to yellow and is naked eye detectable.