Highly selective and sensitive fluorogenic ferric probes based on aggregation-enhanced emission with − SiMe3 substituted polybenzene

In this study, thiophene was linked to polybenzene to generate novel fluorescent probes , namely 3,4-diphenyl-2,5-di(2-thienyl)phenyl-trimethylsilane (DPTB-TMS) with a −   SiMe 3 substituent and 3,4-diphenyl-2,5-di(2-thienyl)phenyl (DPTB) without the −   SiMe 3 substituent, respectively. Both of the two compounds exhibit aggregation-enhanced emission (AEE) properties in tetrahydrofuran/water mixtures due to restricted intramolecular rotation of the peripheral groups, which make the two compounds good candidates for the detection of Fe 3   + ions in aqueous-based solutions. The fluorescence intensity of the two compounds decreases immediately and obviously upon addition of a trace amount of Fe 3   + , and decreases continuously as the amount of Fe 3   + increases. The fluorescence was quenched to 92% of its initial intensity when the amount of Fe 3   + ions reached 6   μmol for DPTB-TMS and to 80% for DPTB in the systems, indicating that the compound with the −   SiMe 3 group is a more effective probe. The detection limit was found to be 1.17   μM (65   ppb). The detection mechanism is proposed to be static quenching. DPTB-TMS is highly efficient for the detection of ferric ions even in the presence of other metal ions . In addition, the method is also successfully applied to the detection of ferric ions in water, blood serum, or solid films. This indicates that these polybenzene compounds can be applied as low-cost, high selectivity, and high efficiency Fe 3   + probes in water or in clinical applications.