Fluoranthene-based pyridine as fluorescent chemosensor for Fe

A fluoranthene based fluorescent chemosensor 2-(7,10-diphenyl-fluoranthen-8-yl)-pyridine (B) which shows excellent selectivity towards Fe³⁺ is described. Upon addition of FeCl₃ into the ethanol solution of B, it exhibits a great decrease of emission intensity against environmental and biological samples. Further experiments demonstrate that Fe(NO₃)₃ has the similar influence as FeCl₃ on the emission spectra of B while Fe₂(SO₄)₃ has no influence on that of B.     

A novel rhodamine-based fluorescent and colorimetric “off-on” chemosensor and investigation of the recognizing behavior towards Fe

A novel rhodamine based probe has been synthesized as an “off-on” chemosensor for Fe³⁺. Upon coordination with Fe³⁺, the probe displayed good brightness and fluorescent enhancement. A linear relationship was observed to exist between the relative fluorescence intensity of this probe and the concentration of Fe³⁺ in the range of 5 μM-20 μM with a detection limit of 5 μM. It offered highly sensitive toward Fe³⁺ over other ions. The recognizing behaviors toward Fe³⁺ have been investigated both experimentally and computationally. It can be expected that Fe³⁺ coordinated with the N atom of thiazole moiety in the probe accompanied by the transferring of electrons of the phenylthiazole resulted in the opening of the spiro-ring.     

A highly selective chemosensor for Cu and Al in two different ways based on Salicylaldehyde Schiff

A novel, easily available colorimetric and fluorescent double-sensor 1 based on Salicylaldehyde bis-Schiff has been investigated in this work. The sensor exhibits highly selective and sensitive recognition toward Cu²⁺ in aqueous solution via a naked eye colour change from colourless to yellow and toward Al³⁺ via a significant fluorescent enhancement in ethanol over a wide range of tested metal ions. This represents the first reported Salicylaldehyde Schiff-based sensor capable of detecting both Cu²⁺ and Al³⁺ using two different modes.     

A fluorescent color/intensity changed chemosensor for Fe by photo-induced electron transfer (PET) inhibition of fluoranthene derivative

A fluorescent color/intensity changed fluoranthene derivative chemosensor for Fe³⁺ has been prepared and confirmed by ¹H-NMR, ¹³C-NMR, HRMS, and crystal data, which displays a high selectivity and antidisturbance for Fe³⁺ among environmentally and biologically relevant metal ions. Fluorescence studies show that fluorescent emission peak blue shifts about 100 nm with fluorescent intensity enhancing 75-fold, indicating a Fe³⁺-selective dual-emission behavior. Further study demonstrates the detection limit on fluorescence response of the sensor to Fe³⁺ is down to 10⁻⁷ M range. The fluorescence signals of chemosensor can be restored with o-phenanthroline, showing the binding of chemosensor and Fe³⁺ is really chemically reversible.     

Electroanalytical studies on cadmium(II) selective potentiometric sensors based on t-butyl thiacalix[4]arene and thiacalix[4]arene in poly(vinyl chloride)

Cd²⁺-selective sensors have been fabricated from poly(vinyl chloride) (PVC) matrix membranes containing t-butyl thiacalix[4]arene (I) and thiacalix[4]arene (II) as electroactive materials. The addition of sodium tetraphenylborate and the plasticizer 2-nitrophenyl octyl ether has been found to improve the performance of the sensors substantially. The membranes of various compositions of the two thiacalixarenes have been investigated and it was found that the best performance was obtained for the membrane of composition II:PVC:NaTPB:NPOE in the ratio 5:120:3:150. The sensor shows a linear potential response for Cd²⁺ over a wide activity range 3.2 × 10⁻⁶ to 1.0 × 10⁻¹ M with Nernstian compliance (29.5 mV decade⁻¹ of activity) in pH range 4.5-6.5 and a fast response time of ∼8 s. The potentiometric selectivity coefficient values determined by matched potential method indicate excellent selectivity for Cd²⁺ ions over mono-, di- and trivalent interfering cations. The sensor exhibits adequate shelf life (∼3 months) with good reproducibility (S.D. ±0.2 mV) and can also be used in partially non-aqueous media having up to 20% (v/v) methanol, ethanol or acetone content with no significant change in the value of slope or working activity range. The sensor has been used in the potentiometric titration of Cd²⁺ with EDTA. The sensor could be successfully used for the quantification of cadmium in river water samples.     

基于杯[4]芳烃的选择性识别二酸的化学传感器

设计、合成了以杯[4]芳烃为平台,以氨基吡啶基团为双识别位点的新型化学传感器,并用红外光谱、质谱、核磁共振和元素分析方法对其进行了表征。紫外和荧光光谱研究结果表明,该受体分子在二氯甲烷溶液中能选择性识别脂肪二酸,络合常数可达103~104L/mol,络合能力大小顺序为:丙二酸>草酸>丁二酸>戊二酸>已二酸。     

Fluorescent chemosensor for metal ions based on optically active polybinaphthyls and 1,3,4-oxadiazole

Linear chiral polymers P-1 and P-2 were synthesized by the polymerization of (R)-5,5′-dibromo-6,6′-di(4-methylphenyl)-2,2′-bisoctoxy-1,1′-binaphthyl (R-M-1) with 2,5-di(4-vinylphenyl)-1,3,4-oxadiazole (M-2) and 2,5-di(4-tributylstannylphenyl)-1,3,4-oxadiazole (M-3) via Heck and Stille cross-coupling reaction, respectively. The chiral conjugated polymer P-1 can show strong green-blue fluorescence, and the chiral polymer P-2 shows strong blue fluorescence. While the conjugated polymers P-1 and P-2 were used as fluorescent chemosensor for metal ions, their fluorescence can be efficiently quenched on the addition of different metal ions. The obvious quenching effect of the polymers P-1 and P-2 indicates that the intramolecular photoinduced electron transfer (PET) or photoinduced charge transfer (PCT) between the polymer backbone and receptor-ions in the main chain of fluorescent chemosensor can lead to the pronounced fluorescence quenching. The results also show that the chiral polymers P-1 and P-2 incorporating 1,3,4-oxadiazole moiety as the recognition site can act as a special fluorescent chemosensor for the appropriate detection of the sensitive and selective sense of metal ions.     

A minimized fluorescent chemosensor array utilizing carboxylate-attached polythiophenes on a chip for metal ions detection

Chemosensor arrays have a great potential for on-site applications in real-world scenarios.However,to fabricate on chemosensor array a number of chemosensors are required to obtain various optical patterns for multianalyte detection.Herein,we propose a minimized chemosensor array composed of only two types of carboxylate-functionalized polythiophene derivatives for the detection of eight types of metal ions.Upon recognition of the metal ions,the polythiophenes exhibited changes in their fluorescence intensity and various spectral shifts.Although both chemosensors have the same polymer backbone and recognition moiety,only the difference in the number of methylene groups contributed to the difference in the fluorescence response patterns.Consequently,the metal ions in aqueous media were successfully discriminated qualitatively and quantitatively by the chemosensor microarray on the glass chip.This study offers an approach for achieving a minimized chemosensor array just by changing the alkyl chain lengths without the necessity for many receptors and reporters.     

A new rhodamine-based single molecule multianalyte (Cu, Hg) sensor and its application in the biological system

A new single molecule multianalyte sensor, vanillic aldehyde rhodamine 6G hydrazone has been designed for the selective detection of Cu²⁺ and Hg²⁺ ions. UV/Vis spectroscopy indicates that the sensor is a good chromogenic chemosensor for Cu²⁺ in 1:99 (v/v) ethanol-water media. Whereas, other ions, such as Li⁺, Na⁺, Mg²⁺, K⁺, Ca²⁺, Cr³⁺, Mn²⁺, Fe³⁺, Co²⁺, Ni²⁺, Zn²⁺, Ag⁺, Cd²⁺, Ba²⁺, Hg²⁺ and Pb²⁺ failed to generate a distinct response. Fluorescence spectral data reveals that the sensor is an excellent fluorescent chemosensor for Hg²⁺ in aqueous ethanol solution and with no fluorescent response toward other ions. The spectroscopic behavior of the sensor in living cells indicated that it can be used for the detection of Cu²⁺ and Hg²⁺ in environmental and biological systems. Mechanisms for the high selectivity of the sensor to Cu²⁺ and Hg²⁺ are discussed.     

A polymer based fluorescent sensor for Zn detection and its application for constructing logic gates

A polymer-based fluorescent sensor was synthesized by polymerization of (S)-6,6′-dibutyl-3,3′-(di-5-salicylde-ethynyl)-2,2′-binaphthol (M-1) with (R,R)-1,2-diaminocyclohexane (M-2) via nucleophilic addition-elimination reaction. The responsive optical properties of the polymer on transition metal ions were investigated by fluorescence and UV-vis spectra. The polymer (1.0 × 10⁻⁵ mol/L in THF) could emit fluorescence at 550 nm and exhibit high selectivity for sensing Zn²⁺ with 36.1-fold fluorescence enhancement. Three logic gates were designed according to the different fluorescence responses of this polymer sensor to Zn²⁺ and Cu²⁺.     

Antimicrobial ability of Cu-montmorillonite

The antimicrobial abilities of Cu²⁺-montmorillonite to E. coli and S. faecalis were investigated. The minimal inhibitory concentration (MIC) and killing concentration of Cu²⁺-montmorillonite on these two disease-causing species were 10 and 50 ppm, respectively. The powerful antimicrobial property of the Cu²⁺-montmorillonite was discussed in brief.     

Influence of Co and Cu on the phase composition of Zn-Ni alloy

Influence of Co²⁺ and Cu²⁺ on codeposition of Zn-Ni in acetate-chloride electrolyte have been investigated by the potentiodynamic stripping and XRD methods. In our earlier work it has been determined that the quantity of the η-phase in the alloy increased with decrease in the quantity of Ni when codeposition of Zn-Ni took place in acetate-chloride electrolyte. Meanwhile, both the quantity of Ni and that of the η-phase in the alloys decreased, when Co or Cu were incorporated in the alloy. Data of XRD have shown that the quantity of γ-phase in the alloy increased with increase in the quantities of Co²⁺ or Cu²⁺ in acetate-chloride electrolyte. When concentration of [Co²⁺] (0.15 mol dm⁻³) was approximately 19 times as high as that of [Cu²⁺] (0.008 mol dm⁻³), the influence of Co²⁺ and that of Cu²⁺ on the phase composition of alloys were nearly similar.     

A Green Method to Fabricate Polyethyleneimine-Alginate Multilayer Coatings Modified Polyurethane Foam for Cu2+ Adsorption from Aqueous Solution

In this study, flexible polyurethane foam (FPUF) was modified with bio-based coatings composed of polyethylenimine (PEI) and alginate (ALG), fabricated by layer-by-layer (LbL) self-assembly. LbL self-assembled coatings modified FPUFs were studied for their potentials for removing Cu²⁺ ions from aqueous solutions by using batch adsorption technique, as a function of assembled bilayers number, pH value, carrier amount and adsorption time. The maximum adsorption capacity of the modified FPUF was shown to be 54 mg/g for Cu²⁺. Results suggested that the LbL self-assembly could potentially be a promising cost-effective technique for fabricating advanced adsorbent materials for removing pollutants from wastewater.     

Synthesis and characterization of super dye adsorbent hydrogels based on acrylic acid and acryloyl tetrasodium thiacalix[4]arene tetrasulfonate

Acryloyl tetrasodium thiacalix[4]arene tetrasulfonate (ACSTCA) was synthesized via fictionalization of tetrasodium thiacalix[4]arene tetrasulfonate (STCA). Hydrogels based on acrylic acid (AA) (20–70 mol%) and ACSTCA (30–80 mol%) were prepared by solution copolymerization in water using methylene bisacrylamide and ammonium persulfate as crosslinker and initiator, respectively. The gels obtained exhibited a good ability for absorbing water. Swelling of the gels was improved with increase in ACSTCA content in the gel feed. Characterization of the synthesized monomer (ACSTCA) was performed using mass spectrometry and Fourier transform infrared (FTIR), ¹H and ¹³C NMR spectroscopies and the synthesized gels were characterized by FTIR. The thermal and mechanical properties of these copolymers were also studied using TGA and dynamic mechanical thermal analysis. The glass transition temperature and storage modulus of the copolymer were increased with increasing content of ACSTCA in the gel. Thermal stability was improved with increasing ACSTCA content in the structure of the copolymer. The results showed that the synthesized copolymer (ACSTCA‐AA) can effectively remove dye from wastewater. The dye removal capacity of the gels was investigated with a UV?visible spectrophotometer. In addition, the effect of key operation parameters such as the ACSTCA content in the structure of the copolymer, contact time, adsorbent dosage, pH of the solution and temperature on dye removal from aqueous solution was experimentally studied. The equilibrium data were analyzed using the Langmuir and Freundlich adsorption isotherms. The Freundlich isotherms provided a better fit to the data. Results from the kinetic studies revealed that the adsorption of malachite green onto the hydrogels followed a pseudo‐second‐order kinetic model. © 2015 Society of Chemical Industry     

Selective Transport of Cu2+ Ions through Bulk Liquid Membrane System Mediated by Erythromycin Ethyl Succinate

The carrier mediated transport of Cu²⁺ ions from an aqueous medium has been examined. The ability of Erythromycin Ethyl Succinate (EES) as a carrier to form a complex with Cu²⁺ ions and transport them to the receiving phase is reported. The fundamental parameters influencing the transport of Cu²⁺ ions such as the pH in the source and receiving phases and concentration of the stripping agent in the receiving phase have been optimized and accordingly, the amount of Cu²⁺ transported across the liquid membrane after 5 h was 94.3 ± 1.8% in the presence of L-histidine as a suitable stripping agent. Moreover, the selectivity and efficiency of Cu²⁺ ions transport from aqueous solution over other cations in ternary and quaternary mixtures have been investigated. The results indicate that our fabricated membrane is very sensitive toward Cu⁺² ions in the presence of heavy metal ions.     

Novel effective dye sorbents: synthesis and properties of 1,2,3-triazole-modified thiacalix[4]arene polymers based on click chemistry

By introducing 1,2,3-triazole-ester groups on thiacalix[4]arene based on click chemistry and then ammonolysis with ethylenediamine, diethylenetriamine or triethylenetetramine, three novel 1,2,3-triazole-modified thiacalix[4]arene polymers were conveniently prepared in “4+2” condensation mode in ideal yields. The structures of polymers 4a–4c were confirmed by elemental analysis, FTIR and ¹H NMR spectra. The surface morphologies of polymers 4a–4c were investigated by SEM micrographs. The M _n of novel polymers 4a–4c indicated approximately 18–20 calixarene units in each polymer molecule. The dye adsorption abilities of polymers 4a–4c for series of organic dyes (alizarin green, orange I, neutral red (NR), Congo red (CR), orange G (OG), crystal violet, Victoria blue B and methylene blue) were studied by solid–liquid adsorption experiments. The adsorption experimental results implied that they had excellent adsorption abilities for tested organic dyes. The highest adsorption percentage reached 97 % for OG. The best saturation adsorption capacities for NR and CR were as high as 1.282 and 1.407 mmol/g, respectively. These novel polymers possessed stable adsorption abilities in the scopes of pH 5–9 and had good reused properties after desorption. The adsorption mechanism proposed that not only dipole interaction, electrostatic interaction and hydrogen bonding interaction, but also the π–π stacking interaction plays important role in binding dyes.     

A ratiometric fluorescent sensor for zinc(II) with high selectivity

Spectroscopic studies revealed that the compound [N,N′-di(quinoline-2-methylene) -1,2-phenylenediimine] (1) exhibited a rather high selectivity toward Zn²⁺ over other metal ions, even Cd²⁺. In acetonitrile, the red shift of fluorescent emission from 396 nm to 426 nm upon zinc binding is due to the formation of a 1:1 metal/ligand complex.