A novel barbituric-based fluorescent probe with aggregation induced emission for the highly sensitive ratiometric detection of cyanide anions

摘要

A new tetraphenylethylene-based barbituric acid derivative (TPEB) with an aggregation induced emission effect is synthesized as a fluorescent probe for CN-. The fluorescence spectra of TPEB in a DMSO-H2O mixture changed with different water fractions (f(w)). Nano-aggregates of TPEB are formed with the strongest fluorescence emission whenf(w)beyond 60. TPEB displays high selectivity and anti-interference toward CN(-)in DMSO-H2O (f(w)70) system at pH around 6, even in the presence of other competitive anions (AcO-, F-, Cl-, Br-, I-, NO3-, SO42-, ClO4-, PO43-, SCN-, HS-, S(2-)and H2O2). The linear curve is excellently matched between the fluorescence intensity and CN(-)concentration at 500 nm. By the equation 3 sigma/S, the limit of detection of TPEB for CN(-)reaches 0.767 x 10(-6) mol L-1. The probe TPEB operates via intramolecular charge transfer mechanism, attributed to the unique nucleophilic addition reactions between TPEB and CN-, which is further confirmed by LC-MS spectra, Job's plot and DFT calculations. By colorimetry and fluorescence approach, CN(-)ions can be easily detected by the TPEB testing strip. The probe can be used to distinguish the acidity and basicity of the solution qualitatively.