Dipodal fluorescent chemosensor for Cu and resultant complex as a chemosensor for iodide

A dipodal receptor was synthesized by condensation of isophthalaldehyde and p-toluenesulfonylhydrazide. The receptor was found to be selective for Cu²⁺ recognition in CH₃CN. The resultant Cu²⁺ receptor complex selectively recognized iodide through cation displacement assay in a CH₃CN/H₂O (8:2, v/v) solvent system.     

A dual-function chemosensor based on coumarin for fluorescent turn-on recognition of Hg2+ and colorimetric detection of Cu2+ in aqueous media

A novel coumarin derivative CTT was synthesized via the condensation of 7-(N,N-diethylamino) coumarin-3-aldehyde with 5-amino-1,3,4-thiadiazole-2-thiol and its structure was characterized using infrared spectroscopy (IR), ¹H NMR, mass spectrometry (MS) techniques, and elemental analysis. The recognition properties of CTT with metal ions were investigated in CH₃CN–H₂O (v/v = 1/1) solution using UV–vis absorption and fluorescence emission spectrum method. The results showed that CTT could monitor Cu²⁺ and Hg²⁺ simultaneously as a dual-function chemosensor in CH₃CN–H₂O (v/v = 1/1). CTT could be used to detect Cu²⁺ colorimetrically; when using CTT, a color change from yellowish-brown to yellowish-green could be readily observed by the naked eye. CTT showed turn-on fluorescent recognition of Hg²⁺, the fluorescence enhancement was attributed to the inhibited C=N isomerization and the obstructed excited state intramolecular proton transfer (ESIPT) of CTT. The recognition mechanism of CTT for Cu²⁺ and Hg²⁺ was studied by experiments and theoretical calculations, respectively. Therefore, CTT has the ability to be a “single chemosensor for dual targets.”     

A novel lipid droplets-targeting fluorescent probe based on dicyanisophorone and carbazole for Cu2+ and its application

A novel fluorescent probe, LCH , based on dicyanisophorone and carbazole, was prepared for the visual detection of Cu²⁺. The probe LCH could recognize Cu²⁺ by fluorescence quenching in EtOH/H₂O (1/4, v/v) solution, which could be easily identified under the 365 nm UV lamp, and the detection limit was as low as 0.785 μM. The recognition mechanism of probe LCH with Cu²⁺ was determined by combining ¹H NMR titration, MS, and theoretical calculations. Practical application experiments showed that probe LCH could be used to detect Cu²⁺ in the test strip experiments. Cell imaging experiments showed that the probe LCH owned good cell permeability and could be applied to the imaging of Cu²⁺ in HepG2 cells. In addition, fluorescence colocalization experiments showed that LCH could target lipid droplets. These results indicate that the probe LCH will have a good application prospect in environmental detection and clinical medicine.     

Study on the synthesis of novel fluorescent macrocyclic sensors and their sensitive properties for Cu2+ and Fe3+ in aqueous solution

In this work, we synthesised and characterised three novel fluorescence macrocyclic sensors containing optically active dansyl groups. The studies for the interaction of the synthesised compounds with various mental ions (Li⁺, Na⁺, K⁺, Ag⁺, Mg²⁺, Ca²⁺, Ba²⁺, Pb²⁺, Zn²⁺, Co²⁺, Cd²⁺, Hg²⁺, Ni²⁺, Cu²⁺, Mn²⁺, Cr³⁺, Al³⁺, Fe³⁺) were performed by fluorescence titration, Job’s plot, ESI-MS and DFT calculations. The results showed that the sensors 1a–1c displayed selective recognition for Cu²⁺ and Fe³⁺ ions and formed stoichiometry 1:1 complex through PET mechanism in DMSO/H₂O solution (1:1, v/v, pH 7.4 of HEPES). The binding constant (K) and detection limit were calculated.     

Novel naphthalene-based fluorescent chemosensors for Cu2+ and Fe3+ in aqueous media

Three novel compounds bearing 2,7-dihydroxylnaphthalene capable of detecting Cu²⁺ or Fe³⁺ have been synthesised based on photoinduced electron transfer. The ability of these compounds for complex transition metal ions has been studied, and complex stoichiometry for Cu²⁺ and Fe³⁺ complex has been determined in the Tris–HCl (0.01 M DMSO/H₂O (v/v) 1:1, buffer, pH 7.4) solution system by fluorescence titration experiments. These chemosensors form a 1:1 complex with Cu²⁺ or Fe³⁺ and show a fluorescent quenching with a binding constant of (4.46 ± 0.29) × 10³ and (8.04 ± 0.26) × 10⁴, respectively.     

A Highly Sensitive and Selective Fluorescence Chemosensor for Cu2+ and Zn2+ Based on Solvent Effect

A novel fluorescence chemosensor 1 based on (R)‐binaphthyl‐salen can exhibit highly sensitive and selective recognition responses toward Cu²⁺ by "turn‐off" fluorescence quench type in THF/H₂O, and Zn²⁺ by "turn‐on" fluorescence enhancement type in CHCl₃/CH₃CN, respectively, suggesting that solvents can dramatically affect the responsive properties of salen‐based chemosensor. In addition, Cu²⁺ can lead to the most pronounced changes of CD spectra without the influence of solvents, which indicates this kind chemosensor can also be used as a sole Cu²⁺ probe based on CD spectra.     

Dried Biomass of Activated Sludge for Cu2+ Adsorption: Behaviors and Mechanisms

Activated sludge was tested for its ability to remove Cu²⁺ from aqueous solution. The effects of various experimental parameters (initial pH, initial Cu²⁺ concentration, adsorbent dosage, and temperature) on Cu²⁺ adsorption were evaluated. The Langmuir isotherm model well described the adsorption of Cu²⁺ onto activated sludge. The pseudo-second-order kinetic equation was appropriate for describing the kinetic performance of the sorption. Furthermore, Webber–Morris models indicated that the sorption of Cu²⁺ was generally found to involve with the intraparticle diffusion process. Parameters of adsorption thermodynamic suggested that the interaction of Cu²⁺ adsorbed by sludge was spontaneous and exothermic. Activated sludge was characterized by Fourier transform infrared spectroscopy analysis and results showed that active groups such as –OH, –COOH, –NH₂ were involved in Cu²⁺ adsorption. Zeta potential analysis demonstrated inner-sphere adsorption for Cu²⁺ adsorption on sludge.     

Das erste Alkali-Erdalkali-Oxocuprat(II,III): NaBa2Cu22+Cu3+O6

The first Alkaline Alkaline-Earth Oxocuprate (II, III): NaBa₂Cu₂²⁺Cu³⁺O₆ The compound NaBa₂Cu₃O₆ was prepared by heating of Na₂O₂, BaO₂, Cu₂O in closed Ag-tubes. X-ray single crystal investigations led to orthorhombic symmetry, space group D-Fmmm; a = 8.4229; b = 11.4418; c = 14.4063 Å; Z = 8. Cu²⁺ and Cu³⁺ show square planar polygones of four and Na⁺ trigonal prisms of six O^2?. The two barium point positions show coordination numbers C.N. = 8 and 6 + 4. The crystal structure is discussed.     

A Highly Selective Colorimetric and Fluorescent Probe for Cu2+ and Hg2+ Ions Based on a Distyryl BODIPY with Two Bis(1,2,3‐triazole)amino Receptors

A new distyryl boron dipyrromethene (BODIPY) with two bis(1,2,3‐triazole)amino substituents has been prepared by typical Knoevenagel condensation followed by click reaction. The compound selectively binds to Cu²⁺ and Hg²⁺ ions in CH₃CN/H₂O (1:1 v/v) to give remarkably blueshifted electronic absorption and fluorescence bands as a result of inhibition of the intramolecular charge‐transfer process upon binding to these metal ions. The color changes can be easily seen by the naked eye. The binding stoichiometry between this probe and Cu²⁺ ions has been determined to be 1:2 by a Job plot of the fluorescence data with a binding constant of ((6.2±0.6)×10⁹) M ^?2. The corresponding value for Hg²⁺ ions is about sixfold smaller.     

Comparison of the Complexation of Open-Chain and Cyclic N2S2 Ligands with Cu+ and Cu2+

The complexation properties of the open-chain N₂S₂ ligands 1–4 are described and compared to those of analogous N₂S₂ macrocycles 5–7 . With Cu²⁺, the open-chain ligands give complexes with the stoichiometry CuL²⁺ and CuLOH⁺, the stabilities and absorption spectra of which have been determined. The ligand field exerted by these ligands is relatively constant and independent of the length of the chain. With Cu⁺, the species CuLH, CuLH²⁺, and CuL⁺ were identified and their stabilities measured. The redox potentials calculated from the equilibrium constants and measured by cyclic voltammetry agree and lie between 250 and 280 mV against SHE. The comparison between open-chain and cyclic ligands shows that (1) a macrocyclic effect is found for Cu²⁺ but not for Cu⁺, (2) the ligand-field strength is very different for the two types of ligands, and (3) the redox potentials span a larger interval for the macrocyclic than for the open-chain complexes.     

The effect of Cu2+ doping in β-tricalcium phosphate on the hydration mechanism of a brushite cement

Brushite cements show excellent biocompatibility and are therefore an often-used material for bone repair. However, methods to prevent inflammations after surgery are needed. As Cu²⁺ was proven to provide antibacterial properties, as well as other application relevant features, it is a promising additive. Concerning these factors, a brushite cement containing Cu²⁺-doped β-tricalcium phosphate, monocalcium phosphate monohydrate, and phytic acid as setting retarder was investigated with powder and in situ X-ray diffraction, isothermal heat flow calorimetry, in situ ¹H-time domain – nuclear magnet resonance, and pore solution analysis. The influence of Cu²⁺ ions on the hydration kinetics of the brushite cement and the locations of the Cu²⁺ ions after completion of the hydration were the main questions of interest. Heat flow calorimetry showed a significant retardation and deceleration of the hydration with increasing Cu²⁺ content in β-tricalcium phosphate. This effect can be directly correlated to the Cu²⁺ ions, as it was also shown for cements without phytic acid. X-ray diffraction showed brushite as main hydrate phase. Additionally, Cu²⁺-doped cements formed a hydrate phase not assignable by X-ray diffraction, which is assumed to be Cu²⁺ containing. Furthermore, Cu²⁺ was detected in the pore solution after the hydration, and no signs of Cu²⁺ incorporation in the crystal structure of brushite were found.     

A Highly Selective Colorimetric Sensor for Cu2+ Based on Phenolic Group Biscarbonyl Hydrazone

A novel copper selective sensor 2 based on hydrazide and salicylaldehyde has been designed and prepared. Sensor 2 behaves a single selectivity and sensitivity in the recognition for Cu²⁺ over other metal ions such as Fe³⁺, Hg²⁺, Ag⁺, Ca²⁺, Zn²⁺, Pb²⁺, Cd²⁺, Ni²⁺, Co²⁺, Cr³⁺ and Mg²⁺ in DMSO. The distinct color change and the rapid changement of fluorescence emission provide naked‐eyes detection for Cu²⁺. The UV‐vis data indicate that 1:2 stoichiometry complex is formed by sensor 2 and Cu²⁺. The association constant K_s was 3.51×10⁴ mol^?1·L. The detection limitation of Cu²⁺ with the sensor 2 was 2.2×10^?7 mol·L^?1. The sensing of Cu²⁺ by this sensor was found to be reversible, with the Cu²⁺‐induced color being lost upon addition of EDTA.     

Novel coumarin-based containing denrons selective fluorescent chemosesor for sequential recognition of Cu2+ and PPi

In this study, we have successfully synthesized a novel coumarin-based dendrons derivative CD and its chemical structure was characterized by ¹H NMR, ¹³C NMR and ESI-HR-MS. The sensor CD showed an obvious “on-off” fluorescence quenching response toward Cu²⁺ with a maximum quenching efficiency of 99.8%. The CD-Cu²⁺ complex showed an “off-on” fluorescence enhancement response toward PPi over many competitive anions. The detection limit of the sensor CD was 0.29?×?10^?6?M to Cu²⁺ and 2.39?×?10^?9?M to PPi. In addition, the sensor CD showed a 1:1 binding stoichiometry to Cu²⁺ and the sensor CD-Cu²⁺ showed a 2:1 binding stoichiometry to PPi in CH₃CN/HEPES buffer medium (9:1 v/v, pH?=?7.2). The stable pH range of sensor CD to Cu²⁺ and CD-Cu²⁺ to PPi was from 3 to 8.     

X-ray spectroscopic characterization of Cu2+-phenanthroline complexes intercalated in α-zirconium phosphate

X-ray photoelectron spectroscopy provides evidence that when [Cu(phen)₂]²⁺(phen = 1,10-phenanthroline) is diffused between the layers of -zirconium phosphate, the complex species does not remain intact after intercalation, but some Cu-N bonds are broken, replaced with Cu-O bonds and the released nitrogen atoms can now interact with the PO₃-OH groups of the host. XPS also provides evidence for coordination of the Cu²⁺ ions when they are diffused by ion exchange in the phenanthroline--zirconium phosphate intercalation compound. Although Cu²⁺ and phen are in a 1 : 1 molar ratio in the interlayer region of the host, so that a 1 : 1 coordination could be expected between the two species, the characteristic peaks of the uncoordinated phenanthroline, even though at a low intensity, are still present. The differences between the two Cu(II)-intercalation compounds are discussed.     

Determination of Cu2+ in Drinking Water Based on Electrochemiluminescence of Ru(phen)32+ and Cyclam

A convenient and simple electrochemiluminescence (ECL) method was employed to detect trace amounts of Cu²⁺ in drinking water. This method is based on the inhibitory effect of Cu²⁺ on the ECL of Ru(phen)₃²⁺ and 1,4,8,11‐tetraazacyclotetradecane (cyclam) system. ECL intensity of Ru(phen)₃²⁺ was considerably enhanced by the addition of cyclam because of the ECL reaction between them. The ECL intensity of Ru(phen)₃²⁺/cyclam system rapidy decreased with the addition Cu²⁺ because of the formation of chelate complex [Cu(cyclam)]²⁺. Good linear response (R ²=0.9948) was obtained at Cu²⁺ concentration of 1.0×10⁻⁹−1.0×10⁻⁵ mol ⋅ L⁻¹ at glassy carbon electrode in 0.1 mol ⋅ L⁻¹ phosphate buffer (pH 9.0). Observed detection limit of 4.8×10⁻¹⁰ mol ⋅ L⁻¹ satisfied the maximum contaminant level goal (MCLG) for Cu²⁺ set by the US Environmental Protection Agency (US EPA). Applicability of the proposed method was verified by the good reproducibility and stability of the method when applied to determine Cu²⁺ in tap water and simulated wastewater. Thus, a novel ECL detection method was developed for Cu²⁺ detection.     

Highly selective detection of Cu2+ based on a thiosemicarbazone triphenylacetylene fluorophore

A novel thiosemicarbazone fluorophore (3) was successfully synthesized in 3 steps via Sonogashira coupling and Knoevenagel condensation using baker's yeast (Saccharomyces cerevisiae) as a biocatalyst. Compound 3 contains triphenylacetylene, which acts as a fluorophore, and thiosemicarbazone, which acts as a copper probe. Compound 3 exhibited highly selective detection of Cu²⁺ ions based on photoinduced electron transfer (PET) in 10 mM HEPES buffer pH 7.4/propylene glycol (70% (v/v)). A linear relationship was observed for Cu²⁺ concentrations between 0.1 nM and 10 μM, and the detection limit of the method was 0.14 nM. Additionally, 3 was utilized to detect Cu²⁺ in wastewater with satisfactory results, which highlighted its potential for real sample applications.     

Voltammetric Simultaneous Determination of Cu2+, Cd2+ and Pb2+ in Full Aqueous Medium Using Organic Nanoparticles of Disulfide Based Receptor

Disulfide based receptor was prepared using single step condensation reaction and suspended into organic nanoparticles to extend its practical application in aqueous samples. The prepared nanoparticles were used for the simultaneous recognition of three different metallic species (Cu²⁺, Cd²⁺, and Pb²⁺) in aqueous media through voltammetric studies. These metals can be determined simultaneously and without interferences from any of the other potential interferent metal ions, as different signals are displayed in cyclic as well as differential pulse voltammograms, with a detection limit of 193.0 nM for Cu²⁺, 52.0 nM for Cd²⁺ and 32.0 nM for Pb²⁺. The study was extended to real sample analysis by preparing the artificial mixtures of said metal ions.     

Solid-state electrode with a Cu(I)-based membrane hydrophobised by PTFE for the measurement of Cu2+ and I−

The preparation of CuI + Ag₂S and Cu₂[HgI₄] + Ag₂S membranes hydrophobised by PTFE is described. The pressed membranes mounted in a multi-purpose “all-solid-state” electrode body have been examined as electrochemical sensors for Cu²⁺ and I^? ions. For the electrode with (CuI + Ag₂S + PTFE)-membrane experimental slopes of 29 mV(pCu)^?1 and 62 mV(pI)^?1 were obtained, in good agreement with the theoretical values. For practical measurement in solutions where both Cu²⁺ and I^? can be present, the investigated electrode offers certain advantages in comparison with a commercial Cu-ISE.     

A coumarin based highly selective fluorescent chemosensor for sequential recognition of Cu2+ and PPi

In this study, we have successfully synthesized a new coumarin based fluorescent chemosensor 1, in which tren and quinolone are introduced as receptors for sequential recognition of Cu²⁺ and PPi. The structure of chemosensor 1 was characterized by ¹H NMR, ¹³C NMR and ESI-HR-MS. Sensor 1 showed an obvious “on-off” fluorescence quenching response toward Cu²⁺, and the quenching efficiency reached a maximum of 99.6% with the addition of 20 equiv. of Cu²⁺. The 1-Cu²⁺ complex showed an “off-on” fluorescence enhancement response toward PPi over many competitive anions, especially HPO₄^2? and H₂PO₄^?. The detection limit of sensor 1 was 1.9?×?10^?6?M to Cu²⁺ and 5.96?×?10^?8?M to PPi. In addition, sensor 1 showed a 1:1 binding stoichiometry to Cu²⁺ and sensor 1-Cu²⁺ showed a 2: 1 binding stoichiometry to PPi in CH₃CN/HEPES buffer medium (9:1 v/v, pH?=?7.4). The stable pH range of sensor 1 to Cu²⁺ and 1-Cu²⁺ to PPi was from 4 to 8.     

A fluorescent chemosensor for Cu2+ ions and its application in cell imaging

A new on-off fluorescent probe 1 for Cu²⁺ based on Schiff base compound was designed and synthesized by one-step reaction. The single probe 1 exhibited strong green fluorescence emission. A fluorescence quenching effect and faint color change were observed as soon as the Cu²⁺ was added to the probe system in H₂O/EtOH (v/v = 8:2, HEPES buffer, 0.05 M, pH = 7.4) solution. Other common metal cations did not cause the changes in the fluorescence and color of the probe 1. The optical properties were studied by the fluorescence emission and UV–Vis spectra. Meanwhile, the geometry optimizations of probe 1 and the [1-Cu²⁺] coordination complexes were also carried out by DFT using the Gaussian 09 program, in which the B3LYP function was used. Based on experimental measurement and theoretical analysis, we can know that the combination ratio of the probe and Cu²⁺ is 2:1 and the limit of detection (LOD) is as low as 5.3 × 10^?9 M Besides, the probe 1 was also used to analyze the Cu²⁺ in living cells.