X.H. Jiang

A cyanide-triggered hydrogen-bond-breaking deprotonation mechanism: fluorescent detection of cyanide using a thioacetohydrazone-functionalized bispillar[5]arene

A novel sensor (AHP5) comprising a thioacetohydrazone-bridged bispillar[5]arene was developed and shown to fluorescently sense cyanide ions. The sensor manifested a response specific to cyanide over other common anions (SCN−, AcO−, HSO4−, H2PO4−, I−, Br−, ClO4−, Cl−, and F−) in DMSO/H2O (9 : 1, v/v) solution. Upon treatment with cyanide, AHP5 exhibited a significant fluorescence response accompanied by marked changes in its fluorescence spectra. Furthermore, competitive anions had no obvious influence on the probing behavior. Notably, investigation of the recognition mechanism indicated that AHP5 recognized CN− through a deprotonation procedure accompanied by the breaking of intermolecular hydrogen bonds. Furthermore, the sensor was successfully applied to the detection of cyanide in cyanide-containing water samples.

Tri-pillar[5]arene-based multi-stimuli-responsive supramolecular polymers for fluorescence detection and separation of Hg2+

A novel tripodal organic gelator (JP5) decorated with three pillar[5]arene tails was designed, synthesized and thoroughly characterized. The stable supramolecular polymer JP5G was obtained within 0.5 minutes by the self-assembly of gelator JP5 in cyclohexanol via C–H⋯π, π⋯π stacking, vdW forces and hydrogen bonding interactions. Interestingly, the supramolecular polymer JP5G showed strong aggregation-induced emission (AIE) and could respond to multiple external stimuli. Simultaneously, JP5G presented special selectivity and high sensitivity for Hg2+; the fluorescence detection limit of JP5G for Hg2+ is 1.02 × 10−8 M. In addition, the JP5G xerogel could effectively remove Hg2+ from water. Whats more, a thin film based on the supramolecular polymer (JP5G) was prepared that could act as a convenient test kit for the detection of Hg2+. The use of tri-pillar[5]arene to construct a tripodal pillar[5]arene-based organic gelator constitutes a novel and efficient method for the design and synthesis of novel functional supramolecular polymers.

A biacylhydrazone-based chemosensor for fluorescence ‘turn-on’ detection of Al3+ with high selectivity and sensitivity

ABSTRACT A simple Al3+ fluorescent chemosensor (1) based on diacylhydrazone has been designed and synthesized by the condensation reaction of 2-hydroxy naphthaldehyde and metaphthalic hydrazide. The chemosensor 1 displays a specific and sensitive response to Al3+ over other cations in DMSO solution. Upon the addition of DMSO solution of Al3+, the sensor 1 shows an immediate fluorescence ‘turn-on’ response and emitting strong blue emission with visible color change from colorless to green. The fluorescence quantum yield enhanced from 7.24% to 48.68%. Meanwhile, the fluorescence and UV absorption spectra detection limits of the chemosensor 1 for Al3+ were 2.0 × 10−7 M and 5.6 × 10−7 M respectively, indicating the high sensitivity of 1 to Al3+. Furthermore, test strips based on 1 were fabricated, which could be used as a convenient test kit for the detection of Al3+ and an efficient Al3+ controlled fluorescent security display materials. Graphical Abstract