BingBing Shi

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 dual-channel Hg 2+ chemosensor based on an easy to prepare double naphthalene Schiff base

A non-sulfur chemosensor based on an easy to prepare double naphthalene Schiff base is reported for the colorimetric and fluorometric dual-channel sensing of Hg2+ ions by taking advantage of the twisted intramolecular charge transfer (TICT) mechanism. This work provides a novel approach for the selective recognition of mercury ions. Moreover, this sensor serves as a potential recyclable component in sensing materials and the complex L-Hg2+ (L = 1-[(2-naphthalenylimino)methyl]-2-naphthalenol) can therefore be used as a fluorescent sensor for iodine anions. Notably, the color changes are very significant and all the recognition and recycling processes can be observed by the naked eye.

A simple Michael acceptor type quinoline derivative for highly selective sequential recognition of CN− and Cu2+ in aqueous solution

A 2-(quinolin-2-ylmethylene) malononitrile (6) chemosensor has been designed and synthesized. The fluorogenic properties of 6 toward different anions and metal ions were investigated in DMSO/H2O (1 : 9, v/v) solution. Probe 6 exhibits high selectivity and sensitivity (5.09 × 10−8 M) to CN− as fluorescence “off–on” behavior through Michael addition. Moreover, the in situ formed 6-CN− is further utilized to sense the Cu2+ through complexation reaction with high selectivity and fluorescence quenching performance in aqueous water. Probe 6 has selectively detected CN− in real water sample, and on test strips. The FTIR, 1HNMR and ESI-MS spectroscopy supported the proposed mechanism of interaction.

A cationic water-soluble pillar[5]arene: synthesis and host–guest complexation with long linear acids

A cationic water-soluble pillar[5]arene has been synthesized and revealed to encapsulate linear acids in neutral, alkaline, and acidic conditions, driven by the hydrophobic and hydrogen bond interactions. A higher guest hydrophobicity contributes to a higher host affinity. Methanoic acid (A1) and acetic acid (A2) do not show any affinity for the host at all, because they are too hydrophilic for the host to compete with water.

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.

Recognition of dihydrogen phosphate ions using the cadmium complex of 2-pyridine-1H-imidazo[4,5-b]phenazine: utilization of the mechanism of twisted intramolecular charge transfer, long wavelength emission

A long wavelength emission fluorescent and colorimetric chemosensor with high selectivity for H2PO4− ions was designed and synthesized according to the twisted intramolecular charge transfer (TICT) mechanism. The sensor bears a 2-pyridine-1H-imidazo[4,5-b]phenazine and Cd2+ metal complex, which showed brilliant fluorescent and colorimetric response for H2PO4− anions in aqueous solution. The detection limit of the sensor towards H2PO4− is 2.8 × 10−6 M, and other anions, including F−, Cl−, Br−, I−, AcO−, HSO4−, ClO4− and CN−, had nearly no influence on the probing behavior. The test strips based on the 2-pyridine-1H-imidazo[4,5-b]phenazine and Cd2+ metal complex (S2–Cd) were fabricated, which could act as convenient and efficient H2PO4− test kits.

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.

Copillar[5]arene–based supramolecular polymer gel: controlling stimuli–response properties through a novel strategy with surfactant

A new functionalized copillar[5]arene derivative containing one 1,4-bis(hexadecyl)benzene unit and four 1,4-dimethoxybenzene units has been synthesized and revealed to present self-assembly driven by C–H⋯π and cation⋯π interactions in CD3CN solution, giving a constructed supramolecular polymer gel accompanied by aggregation-induced enhanced emission (AIEE) of fluorescence. When adding a surfactant bearing hexadecylpyridinium chloride into the gel, the electron-poor compound penetrated into the rich-electron cavity of DCP5-16, forming host–guest complexation and causing fluorescence quenching due to the electron transfer. This approach may open up routes to novel stimuli–responsive supramolecular materials.

A silver-induced metal-organic gel based on biscarboxyl-functionalised benzimidazole derivative: stimuli responsive and dye sorption

A multi-responsiveness supramolecular metal-organic gel (MOG) has been prepared by using silver (I) nitrate and a simple ligand (L17) based on a biscarboxyl-functionalised benzimidazole derivative. The MOG that displays the formation of well-developed nanofibrillar networks composed of intertwined fibres was characterised by using field emission scanning electron microscopy (FESEM), Fourier transform infrared (FT-IR) spectroscopy and powder X-ray diffraction (XRD) techniques. The FT-IR spectra and XRD show that supramolecular MOG was formed through an effective coordination of the ligand and Ag+. This MOG reveals outstanding reversible sol–gel transitions induced by changes of temperature and pH, as well as by addition of NH4OH, ethylene diamine tetraacetic acid and Na2S. In addition, the MOG also shows a good ability in dye sorption. These results demonstrate that this multichannel responsive smart MOG has the potential to be widely applied in materials science.