Dual-response fluorescence sensor for detecting Cu2+ and Pd2+ based on bis-tetraphenylimidazole Schiff-base

Although the fluorescence sensors for Cu 2+ or Pd 2+ had been prepared, the sensor of in-situ detecting both Cu 2+ ion and Pd 2+ ion in aqueous media was rarely concerned. Herein, a bis-tetraphenylimidazole Schiff-base ( Bis-TPI ) with aggregation-induced emission was designed and prepared in yield of 88%. Bis-TPI displayed strong red fluorescence at 550–650 nm in aqueous media and selectively response on detecting Cu 2+ and Pd 2+ with quenched fluorescence. The detection limits attained 8.3 × 10 -7 M for Cu 2+ and 9.2 × 10 -7 M for Pd 2+ , respectively. The mutual interference on detecting Cu 2+ and Pd 2+ in their coexistence system was eliminated by the masking reagent of adenosine triphosphate for Cu 2+ , realizing the detection of Cu 2+ and Pd 2+ sequentially. The sensing mechanism of 1:1 binding system was supported by FT-IR spectra, binding MS spectra, 1 H NMR spectra and fluorescence Job’s plot. Moreover, Bis-TPI showed good fluorescence bioimaging property and achieved in-situ detection on Cu 2+ and Pd 2+ in living-cell system, implying the application prospect on in-situ sensing Cu 2+ and Pd 2+ in both vitro environment and vivo assay.