You-Ming Zhang

Double Metal Ions Competitively Control the Guest-Sensing Process: A Facile Approach to Stimuli-Responsive Supramolecular Gels

A facile approach to the design of stimuli-responsive supramolecular gels (SRSGs) termed double-metal-ion competitive coordination control is reported. By this means, the fluorescence signals and guest-selective responsiveness of the SRSGs are controlled by the competitive coordination of two different metal ions with the gelators and the target guest. To demonstrate this approach, a gelator G2 based on multiple self-assembly driving forces was synthesized. G2 could form Ca(2+) -coordinated metallogel CaG with strong aggregation-induced emission (AIE). Doping of CaG with Cu(2+) results in AIE quenching of CaG and formation of Ca(2+) - and Cu(2+) -based metallogel CaCuG. CaCuG could fluorescently detect CN(-) with specific selectivity through the competitive coordination of CN(-) with the Cu(2+) and the coordination of Ca(2+) with G2 again. This approach may open up routes to novel stimuli-responsive supramolecular materials.

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 colorimetric chemosensor for detection of nickel ions in aqueous solution

A highly selective chemosensor LX based on quinoline was described, which could instantly detect Ni2+ in aqueous solution with specific selectivity and high sensitivity. The addition of Ni2+ to sensor LX induced a remarkable color change from yellow to red; this sensing procedure could not be interfered by other coexistent competitive cations such as Fe3+, Co2+, and Cu2+. Thus LX could be used as a potential Ni2+ colorimetric and naked-eye chemosensor. Moreover, test strips based on sensor LX were fabricated, which could act as a convenient and efficient Ni2+ test for “in-the-field” measurement of Ni2+.

A novel colorimetric HSO4(-) sensor in aqueous media.

A novel and sensitive anion receptor 3, bearing Schiff base structure, nitrophenyl azobenzol and carboxyl groups, was developed and characterized as a single chemosensor for the recognition of HSO(4)(-) anion. The different responses of UV-vis spectra and color changes of 3 could be applied to the recognition for HSO(4)(-) over other anions such as F(-), CI(-), Br(-), I(-), AcO(-), H(2)PO(4)(-) and CIO(4)(-) by the naked eye. Furthermore, the anion binding interaction of receptor-anion was also studied using UV-vis and (1)H NMR titration which revealed that 3 displayed a remarkable binding ability for the HSO(4)(-) with an association constant K(a)=6.59×10(4) M(-1). And the detection limitation of HSO(4)(-) with the receptor 3 was 2.0×10(-6) mol L(-1) in aqueous solution. Most importantly, the qualitative detection of HSO(4)(-) using receptor 3 was attempted with test kit which was made from receptor 3.

AN EFFICIENT SYNTHESIS OF POLYMETHYLENE-BIS-AROYL THIOUREA DERIVATIVES UNDER THE CONDITION OF PHASE-TRANSFER CATALYSIS

Reaction of polymethylene diamine with aroyl chloride and ammonium thiocyanate under the condition of solid–liquid phase-transfer catalysis using polyethylene glycol-400 (PEG-400) as the catalyst yielded polymethylene-bis-aroyl thiourea derivatives 3a–q in good-to-excellent yield. The products have been characterized by analytical and spectral (IR and H1 NMR) data.

A novel 5-mercapto triazole Schiff base as a selective chromogenic chemosensor for Cu2+

A novel colorimetric cation sensor bearing phenol, thiol and HCN groups was designed and synthesized. In a DMSO/H2O (9:1, v/v) solution, the sensor exhibited highly selective recognition of Cu2+ among a range of metal ions tested. In the presence of Cu2+, solutions of the sensor underwent a dramatic color change from colorless to yellow, while the presence of other metal cations such as Zn2+, Pb2+, Cd2+, Ni2+, Co2+, Fe3+, Hg2+, Ag+ and Ca2+ had no effect on the color. The detection limit of the sensor toward Cu2+ is 8.0×10(-7) M and an association constant Ka of 4.3×10(5) M(-1) was measured. The sensing of Cu2+ by this sensor was found to be reversible, with the Cu2+-induced color being lost upon addition of EDTA.

SYNTHESIS AND BIOLOGICAL ACTIVITY OF N-AROYL-N′-SUBSTITUTED THIOUREA DERIVATIVES

A series of N-aroyl-N′-substituted thiourea derivatives have been prepared in good to excellent yields under the condition of solid-liquid phase transfer catalysis using polyethylene glycol-400(PEG-400) as the catalyst. The products have been characterized on the basis of analytical and spectral (IR and 1H NMR) data. The promoting effects of some compounds on wheat growth have been tested preliminary.

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.

Pillar[5]arene‐Based Supramolecular Organic Framework with Multi‐Guest Detection and Recyclable Separation Properties

The selective detection and separation of target ions or molecules is an intriguing issue. Herein, a novel supramolecular organic framework (SOF-THBP) was constructed by bis-thioacetylhydrazine functionalized pillar[5]arenes. The SOF-THBP shows a fluorescent response for Fe3+ , Cr3+ , Hg2+ and Cu2+ ions. The xerogel of SOF-THBP shows excellent recyclable separation properties for these metal ions and the absorption rates were up to 99.29 %. More interestingly, by rationally introducing these metal ions into the SOF-THBP, a series of metal-ion-coordinated SOFs (MSOFs) such as MSOF-Fe, MSOF-Hg and MSOF-Cu were constructed. These metal ions coordinated MSOFs could selectively sense F- , Br- , and l-Cys, respectively. The detection limits of these MSOFs for F- , Br- and l-Cys were about 10-8  m.

A colorimetric and fluorescent cyanide chemosensor based on dicyanovinyl derivatives: Utilization of the mechanism of intramolecular charge transfer blocking

Chemosensor (CS1) was designed and synthesized by simple green chemistry procedure. CS1 exhibited both colorimetric and fluorescence turn-off responses for cyanide (CN(-)) ion in aqueous solution. The probe showed an immediate visible color changes from yellow to colorless and green fluorescence disappearance when CN(-) was added. The mechanism of chemosensor reaction with CN(-) was studied using (1)HH NMR and (13)C NMR spectroscopies and mass spectrometry. Moreover, test strips based on the sensor were fabricated, which served as convenient and efficient CN(-) test kits.