A coumarin based ratiometric fluorescent probe for the detection of Cu and mechanochromism as well as application in living cells and vegetables.

In this paper, a novel coumarin-derived fluorescent probe NY was designed and synthesized. NY displayed a significant ratiometric fluorescence response towards Cu in PBS buffer (10 mM, pH = 7.4), with the emission wavelength blue-shifted from 580 to 495 nm, and a fluorescence change from orange to green was evident under a 365 nm UV light. Meanwhile, NY had the advantages of high selectivity, short response time (5 min), low detection limit (1.3 × 10 M) and large binding constant (1.45 × 10 M) towards Cu. The binding mechanism between NY and Cu was elucidated by FT-IR, H NMR titration, TOF-MS and Job's plot analysis. In addition, NY was successfully employed in the detection of Cu within environmental water and vegetable samples with satisfactory results. Laser confocal microscopy imaging results showed that NY could easily penetrate HeLa cells membrane to target mitochondria and image Cu in living cells. Furthermore, NY demonstrated mechanochromic properties by exhibiting orange-red fluorescence when subjected to mechanical grinding.