New fluorescent chemosensors based on mononuclear copper complex for highly selective and sensitive detection of...

Three new probes, named, [Cu(L1)2]Cl2 (C1), [Cu(L2)2]Cl2 (C2) and [Cu(L3)2]Cl2 (C3) were synthesized and well characterized. The probes C1, C2 and C3 were successfully achieved for the efficient detection of PO43- as turn-on fluorescence chemosensors in DMSO/H2O (v:v = 2:8, Tris-HCl pH = 7.20). The limit of detection (LOD) of probes C1, C2 or C3 for PO43- could be as low as 0.029 μM, 0.048 μM, 0.079 μM, respectively, which were effectively applied for the determination of the PO43- concentration in environmental water of swimming pool. What's more, the binding constant between probes C1, C2, C3 and PO43- are estimated to be 3.11 × 107 M-1 (R2 = 0.9992), 1.84 × 107 M-1 (R2 = 0.9956), 1.93 × 107 M-1 (R2 = 0.9976), respectively. The proposed mechanism for the "on-off-on" fluorescence response was confirmed by ESI-MS and fluorescence spectrum. Moreover, the membrane-permeable probe C1 was successfully demonstrated in monitoring of PO43- in cultured HepG2 cells.