A new fluorescent probe X based on 2-pyridin-2-ylethanamine and benzimidazo[2,1-a]benz[de]isoquinoline-7-one-12-carboxylic acid was designed and synthesized for the detection of Fe³⁺ and PPi. X showed high sensitivity and selectivity for Fe³⁺ in the presence of other competing metal ions in DMF/H₂O buffer solution. The limit of detection for Fe³⁺ was calculated from the titration curve to be 6.7 × 10⁻⁷ M. The Job's plot confirmed a 1 : 1 stoichiometry between the probe and Fe³⁺, and the complexation stability constant was calculated to be 7.46 × 10³ M⁻¹. Moreover, the fluorescence intensity of the probe was recovered after addition of the PPi. X could act as a fluorescence “ON–OFF–ON” probe for the sequential detection of Fe³⁺ and PPi. The binding mode and sensing mechanism of X with Fe³⁺ was verified by DFT/TDDFT calculations using Gaussian 09.

中文翻译：

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一种新型的“ ON-OFF-ON”荧光探针，用于基于2-吡啶-2-吡啶胺和苯并咪唑并[2,1- a ]苯并[ de ]异喹啉-7-one-12-的顺序检测Fe ³⁺和PPi羧酸†

设计并合成了基于2-吡啶-2-吡啶胺和苯并咪唑并[2,1- a ]苯并[ de ]异喹啉-7-one-12-羧酸的新型荧光探针X，用于检测Fe ³⁺和PPi 。X在DMF / H ₂ O缓冲溶液中存在其他竞争性金属离子时，对Fe ³⁺具有很高的灵敏度和选择性。根据滴定曲线计算出的Fe ³⁺的检出限为6.7×10 ^-7M。Job 's图确认了探针与Fe ³⁺之间的化学计量比为1：1 ，络合稳定性常数为7.46。 ×10 ³ M^-1。此外，在添加PPi后恢复了探针的荧光强度。X可以用作荧光“ ON–OFF–ON”探针，用于顺序检测Fe ³⁺和PPi。X^离子与Fe ³⁺的结合模式和感应机理通过使用高斯09的DFT / TDDFT计算得到验证。