'Turn-on' Fluorescence Chemosensor Based Probing of Cu2+ with Excellent Sensitivity: Experimental Study, DFT Calculations and Application in Living Cells and Natural Waters

摘要

Developing selective, precise, and rapid determination methods for Cu2+ sensing is of great significance for biological systems, public health, and environmental protection. Hence, a new coumarin-based fluorescent chemosensor 3-((E)-(((E)-3,5-di-tert-butyl-2-hydroxybenzylidene)hydrazono) methyl)-7-(diethylamino)-2H-chromen-2-one (HBAC) for Cu2+ sensing in MeOH:H2O (80 : 20, v:v, pH=7 PBS buffer) media has been constructed. HBAC responded to Cu2+ with high selectivity and exhibited a relatively low LOD of 7.0 nM and similar to 22-fold fluorescent enhancement at 461 nm with the addition of Cu2+ (0.0-5.0 mu M). The reaction mechanism of the HBAC-Cu2+ system has been fully examined by MALDI-TOF-MS, FT-IR, and time dependent-density functional theory (TD-DFT) calculations. The sensing mechanism was occurred due to the chelation enhanced fluorescence (CHEF) and inhibition of PET phenomena. Furthermore, the chemosensor HBAC for Cu2+ sensing in living systems and natural spring water samples has been successfully utilized, suggesting that the prepared HBAC is an appropriate chemosensor for examining Cu2+ in biological and environmental systems.