Wen-Juan Qu

Copillar[5]arene-based supramolecular polymer gels

Copillar[5]arene-based supramolecular polymer gels were obtained in acetonitrile. These supramolecular polymer gels were driven by C–H⋯π interactions, presented two phases as time goes on, and finally formed a supramolecular organic framework. Notably, the supramolecular polymer gels showed reversible gel–sol phase transitions upon heating and cooling. Moreover, the gels exhibit excellent self-healing properties.

A highly selective fluorescent chemosensor for iron ion based on 1H-imidazo [4,5-b] phenazine derivative

Two kinds of fluorescent sensors (S and S1) for Fe(3+) bearing 1H-Imidazo [4,5-b] phenazine derivatives have been designed and synthesized. Between the two sensors, S showed excellent fluorescent specific selectivity and high sensitivity for Fe(3+) in DMSO solution. The test strip based on S was fabricated, which could act as a convenient and efficient Fe(3+) test kit. The recognition mechanism of the sensor toward Fe(3+) was evaluated by MS, IR and XRD. The detection limit of the sensor S towards Fe(3+) is 4.8×10(-6)M. And other cations, including Hg(2+),Ag(+), Ca(2+), Cu(2+), Co(2+), Ni(2+), Cd(2+), Pb(2+), Zn(2+), Cr(3+), and Mg(2+) had no influence on the probing behavior.

A highly selective colorimetric and “Off–On” fluorescent chemosensor for fluoride ions and its application as a molecular-scale logic device

A new sensor 2,2′-((1E,1′E)-((3,3′-dimethyl-[1,1′-biphenyl]-4,4′-diyl)bis(azanylylidene))bis(methanylylidene))diphenol (YT) based on the combination of phenolic hydroxy and imine groups was used as an efficient colorimetric and “turn on” fluorescent sensor for fluoride anions. The receptor exhibits high selectivity and sensitivity for sensing F−. Furthermore, the enhanced fluorescence caused by fluoride could be reset upon the addition of calcium ions to the complex solution. The fluorescence changes of YT upon the addition of F− and Ca2+ were utilized as an INHIBIT logic gate at the molecular level, using F− and Ca2+ as chemical inputs and the fluorescence intensity signal as the output.

A reversible fluorescent chemosensor for the rapid detection of mercury ions (II) in water with high sensitivity and selectivity

A water-soluble, non-sulfur, 2,4-dimethyl-7-amino-1,8-naphthyridine (Z1) chemosensor was synthesized to fluorescently sense Hg2+ in water. The single crystal structure of the sensor confirmed the synthesis results. The detection limit of the sensor towards Hg2+ was 8.859 × 10−8 M, which indicates its high detection sensitivity. The immediate response of Z1 to Hg2+ provided a real-time detection method.

An easy prepared double naphthalene Schiff-base for highly selective sensing of cyanide via the dipolymer in aqueous solution

A highly selective chemosensor based on an easy-to-prepare double naphthalene Schiff-base (R) is reported for the colorimetric and fluorometric dual-channel sensing of cyanide by taking advantage of the dipolymer in DMSO–H2O (8:2, v/v) HEPES buffer (pH 7.21) solution. The detection of cyanide was carried out via the nucleophilic attack of cyanide anion on the C = O of the probes tautomer with a 1:1 binding stoichiometry, which could be confirmed by 1H NMR and MS studies. The detection limit of R for the determination of cyanide was estimated to be 8.434 × 10− 9 M. And other anions, including F− , Cl− , Br− , I− , AcO− , , , , and , had nearly no influence on the probing behaviour. The test strips based on R were fabricated, which could act as convenient and efficient CN− test kits.

A turn-on fluorescent sensor for relay recognition of two ions: from a F−-selective sensor to highly Zn2+-selective sensor by tuning electronic effects

A simple ion sensor bearing quinoline and an amide group was designed and synthesized, which showed both colorimetric detection for F− and a fluorescence turn-on response for Zn2+. Moreover, sensor L2 can distinguish F− and Zn2+ via different sensing mechanisms (deprotonation for F−; inhibition of photo-induced electron transfer (PET) and excited-state intramolecular proton transfer (ESIPT) for Zn2+). Meanwhile the distinct color change and the rapid enhancement of fluorescence emission provide naked eye detection. This sensor achieved the detection of two ions which does not need to rely on two different probes: utilization of the innate reactivity of only one probe could achieve a dual recognition purpose in a tandem fashion.

A highly selective fluorescent chemosensor for successive detection of Fe3+ and CN- in pure water

Abstract A water-soluble fluorescent chemosensor (D) based on 1, 8-naphthalimide derivative has been designed and synthesised as a new fluorescent sensor for successive detection of Fe3+ and CN−. Fluorescence measurements show that chemosensor D has excellent fluorescent-specific selectivity and high sensitivity for Fe3+ over many other metal ions in pure water. Moreover, the complex of D and Fe3+ (D–Fe3+) displayed high sensitivity for CN− over many other anions in the same medium. Even more important, the recognition of the sensor D for Fe3+ and D–Fe3+ complex for CN- could be used successfully in pure water. The test strips based on D and D–Fe3+ exhibited good selectivity to Fe3+ and CN,- respectively, we believe the test strips could serve as convenient and efficient Fe3+ and CN− test kits.

Novel fluorescent cyanide-selective chemosensor based on a functionalised pillar[5]arene copper(II) complex

Abstract As a novel macrocyclic host, pillar[5]arene can selectively recognise guest molecules in organic solvents. In this study, a fluorescent chemosensor composed of a functionalised-pillar[5]arene and Cu2+ metal complex (PN–Cu), which shows good selectivity for CN− anions, has been designed and synthesised. Complexation between PN–Cu and anions has been probed by means of various fluorescence-based methods. PN–Cu, as a turn-on fluorescence chemosensor showed high selectivity towards CN− ions in comparison to other anions, and its detection limit for CN− was calculated as 9.03 × 10−7 M. The PN–Cu sensor can serve as a recyclable component in sensing materials. Moreover, the interaction between the singly functionalised pillar[5]arene and Cu2+ has been probed through various tests. Based on the remarkable selectivity of the chemosensor PN–Cu, we propose that it might be used as a potential material for CN− recognition. Scheme 2. The proposed sensing mechanism of PN for copper(II) and cyanide in DMSO.

A reversible dual-channel chemosensor for fluoride anion

A colorimetric and fluorescent fluoride probe bearing phenolic hydroxy and imine groups has been designed and synthesised. This receptor could visually and spectroscopically recognise F− with high selectivity over other anions. After the addition of fluoride ions to the solution of ([1,1′-biphenyl]-4,4′-diylbis (azanylylidene)) bis (methanylylidene)) bis (naphthalen-2-ol) (TY), since the deprotonation reaction occurred between the sensor and fluoride, the fluorescence intensity of the solution changed significantly. Furthermore, the quenched fluorescence caused by fluoride ions could be recovered upon the addition of calcium ions to this complex solution. This resulted in an ‘OFF-ON-OFF’ type sensing. In particular, an IMP logic gate has been proposed using the output obtained from the fluorescence studies. The fluorescence, UV-vis titration and 1H NMR titration experiments indicated that the effects might occur via a combined process including hydrogen bond and deprotonation between the sensor and F− .

Highly selective and sensitive chemosensor based on 2,3-diaminophenazine hydrochloride for the detection of cyanide in pure water and its application in plant seed samples

In this study, we prepared an efficient chemosensor based on 2,3-diaminophenazine hydrochloride, and it exhibited good dissolvability in water; more importantly, it could act as an efficient chemodosimeter for the selective detection of CN− in pure water. Upon reacting with CN−, 2,3-diaminophenazine hydrochloride (Q1) displayed a remarkable visible and fluorescence response simultaneously with significant changes in both absorption and fluorescence spectra. Furthermore, the absorption and fluorescence detection limits of CN− were 1.95 × 10−7 M and 1.13 × 10−9 M, respectively. For practical applications, test strips based on this chemosensor could serve as convenient CN− detection tools. The chemosensor was also successfully applied to the detection of CN− in plant seeds and several natural water samples.