A relay identification fluorescence probe for Fe3 + and phosphate anion and its applications

A simple relay identification fluorescence probe for Fe 3   + and phosphate anion with “on-off-on” switching was designed and synthesized based on the phenylthiazole and biphenylcarbonitrile. Probe 1 displayed highly selective and sensitive recognition to Fe 3   + in HEPES aqueous buffer (EtOH/H 2 O   =   2:8, v/v, pH   =   7.4) solutions. The optimized structures and HOMO and LUMO of probe 1 and [1-Fe 3   + ] complex were obtained by the density functional theory (DFT) calculations with B3LYP as the exchange and correlation functional using a suite of Gaussian 09 programs. The [1-Fe 3   + ] complex solution also showed a high selectivity toward PO 4 3   − . The lower limits of detection of probe 1 to Fe 3   + and [1-Fe 3   + ] complex to PO 4 3   − were estimated to 1.09   ×   10 −   7   M and 1.86   ×   10 −   7   M. Besides, the probe 1 also was used to detected the target ions in real water sample and living cells successfully.