An Ultra-low Detection Limit Fe 3+ Optical Fiber Fluorescent Sensor Based on a Anti-B 18 H 22 Derivative with Aggregation-induced Emission Enhancement.

A fluorescent Fe 3+ probe ((C 10 H 7 NO 2 ) 2 B 18 H 20 , M1) by introducing two isoquinoline-1-carboxylic acid group into the 6,9-position of anti-B 18 H 22 was designed and synthesized. The structure of M1 was investigated by 1 H NMR, MS, FT-IR and theoretical calculation, and its optical properties were characterized with UV-Vis and PL. M1 showed aggregation induced emission enhancement (AIEE) properties in THF/H 2 O solution, and exhibited an excellent selectivity toward Fe 3+ in THF/H 2 O (v/v, ƒw = 95%) solution with a detection limit of 1.93 × 10 -5  M. The interaction mechanism of probe for detecting Fe 3+ is attributed to the involvement of intramolecular charge transfer (ICT) process. Furthermore, a optical fiber fluorescent Fe 3+ sensor based on M1 sensing film was developed, the detection limit of the optical fiber Fe 3+ fluorescent sensor could be improved to13.8 pM, the ultra-low detection limit is superior to most reported fluorescent probes (or sensors) towards Fe 3+ . This method has the advantages of high sensitivity, anti-interference and easy to operate, and has great potential in the field of the analysis of environmental and biological samples.