Evaluation of heterocumulenic ferrocene derivatives for “click” chemistry type reactions

Azidoferrocene (1), 1,1′-diazidoferrocene (2) and 1,1′-diisothiocyanatoferrocene (3) were subjected to reactions from the repertoire of “click” chemistry, with a view to applications in the post-functionalisation of self-assembled monolayers. The copper-catalysed 1,3-dipolar cycloaddition of 1 and FcCCH (Fc = ferrocenyl) afforded the expected 1,2,3-triazole derivative under anhydrous and anaerobic conditions. Analogous reactions also succeeded with 2 and RCCH (R = Ph, Fc). The Staudinger reaction of 2 with 1,1′-bis(diphenylphosphanyl)ferrocene (dppf) gave the expected bis(iminophosphoranyl)ferrocene in high yield. The nucleophilic addition of 2 equiv. of NHR₂ (R = Et, iPr) to 3 afforded the corresponding thiourea derivative in quantitative yield.     

An “off–on” fluorescence probe for chromium(III) ion determination in aqueous solution

An “off–on” rhodamine-based fluorescence probe for the selective signaling of Cr(III) has been designed by exploiting the guest-induced structure transform mechanism. This system shows a sharp Cr(III)-selective fluorescence enhancement response in 100% aqueous system under physiological pH value and possesses high selectivity against the background of environmentally and biologically relevant metal ions including Cr(VI), Al(III), Fe(III), Cd(II), Co(II), Cu(II), Ni(II), Zn(II), Mg(II), Ba(II), Pb(II), Na(I), and K(I). Under optimum conditions, the fluorescence intensity enhancement of this system is linearly proportional to Cr(III) concentration from 5.0 × 10⁻⁸ to 7.0 × 10⁻⁶ mol L⁻¹ with a detection limit of 1.6 × 10⁻⁸ mol L⁻¹.     

A novel pyrene-based “off–on” fluorescent probe with high selectivity and sensitivity for Hg2+

In this article, a novel “off–on” fluorescent probe 2-(pyren-1-ylmethylene)-1H-indene-1,3(2H)-dione ( PID ) for Hg²⁺ was designed and synthesized. The selectivity, concentration titration, pH titration, time dependence, limit of detection, and recognition mechanism of PID for Hg²⁺ in CH₃CH₂OH/H₂O solution were also investigated. The results indicated that PID exhibited high selectivity, sensitivity, and fast response to Hg²⁺, and the limit of detection was as low as 20.7 nmol/L. In addition, PID could work in a wide pH range, and the determination of Hg²⁺ in water samples showed that it could be used as a potential detection tool in practical application.     

A Heterometallic MOF based on Monofunctional Linker by “One-pot” Solvothermal Method for Highly Selective Gas Adsorption

Heterometallic MOFs, as an important branch of MOF materials, open up a new way to design and synthesize innovative MOF materials. Hence, it has positive significance for the development of MOF materials. By utilizing monofunctional linker CBDA [5,5'-(carbonylbis(azanediyl))-diisophthalic acid], a heterometallic MOF In/Gd-CBDA was obtained under “one-pot“ solvothermal method. The three-dimensional framework exhibits (3,4,6)-connected network belonging to a new topology. In addition, the synthetic conditions that affect the growth of crystal have been studied in detail. Numerous experiments led to the finding that the type and composition of solvents are very important for inducing the recognition of carboxylic acid groups at different positions coordination to diverse metals. Furthermore, the mechanism of this kind of heterometallic MOFs assembled by monofunctional linker under “one-pot” solvothermal method has been clarified, which is mainly related to the steric hindrance of functional groups and the properties of heterometals. Based on ideal adsorbed solution theory (IAST), In/Gd-CBDA shows the efficient selective gas adsorption, especially for equimolar mixtures of CO₂/CH₄ (13) and C₃H₈/CH₄ (321). This work of heterometallic MOF material assembled by monofunctional linker under “one-pot” solvothermal method provides a new platform for the development of MOF materials in terms of enriching the topological family and broadening possibilities in advanced applications.     

Sensitive and selective DNA probe based on “turn-on” photoluminescence of C-dots@RGO

In this study, highly hydrophilic and photoluminescent sheets of reduced graphene oxide decorated with carbon dots (C-dots@RGO), methylene blue (MB), and a probe DNA have been used for the detection of DNA. The photoluminescence of C-dots@RGO is quenched by MB, which is restored in the presence of a target DNA. The combination of the C-dots@RGO, MB, and a DNA probe is selective for perfectly matched DNA over mismatched DNA, mainly because relative to single-stranded DNA, double-stranded DNA intercalates more strongly with MB, but interacts more weakly with RGO. In the presence of a target DNA, MB intercalates with the as-formed double-stranded DNA and is released from the surface of C-dots@RGO, leading to “turn-on” photoluminescence. The practicality of this assay has been validated by the determination of tumor suppressor gene BRCA1, with linearity over the concentration range from 25 to 250 nM and a limit of detection (LOD, at a signal-to-noise ratio of 3) of 14.6 nM. The C-dots@RGO probe provides higher specificity towards target DNA than towards common salts, carbohydrates, amino acids, and proteins found in real samples. Having the advantages of simplicity, cost-effectiveness, selectivity, and sensitivity, the DNA-P/C-dots@RGO–MB probe on microwells has been successfully employed for the detection of DNA, suggesting its potential for multiple analyses of DNA targets when various DNA probes are employed.     

In-column “click” preparation of hydrophobic organic monolithic stationary phases for protein separation

Two types of macroporous organic polymer monoliths based on glycidyl methacrylate (GMA), 4-vinylbenzyl chloride (VBC) and divinylbenzene (DVB) were prepared inside stainless-steel tubes. Azide functionalities were firstly introduced on the surfaces of poly(GMA-co-DVB) and poly(VBC-co-DVB) monoliths to provide reactive sites for click chemistry. With the application of copper(I)-catalyzed (3 + 2) azide-alkyne cycloaddition, an in-column click-modification approach for covalent attachment of long alkyl chains onto polymer monoliths was developed. The column morphology and surface chemistry of the fabricated monolithic columns were characterized by the scanning electron microscopy, mercury intrusion porosimeter, Fourier transform infrared spectroscopy, and elemental analyses, respectively. The chromatographic performances of the “clicked” stationary phases were demonstrated with the high separation efficiency for a variety of proteins within 4 min.     

Mitochondria-targeted fluorescent probe based on vibration-induced emission for real-time monitoring mitophagy-specific viscosity dynamic

Directly monitoring mitophagy-specific viscosity dynamic in living cells is of great significance but remains challenging. Herein, this study reported a novel mitochondria-targeted fluorescent probe DPACDY based on vibration-induced emission(VIE) for monitoring viscosity changes during mitochondrial autophagy. This probe contained N,N’-diphenyl-dihydrodibenzo[a,c]phenazine(DPAC) as the VIE core and two positively charged pyridinium moieties for mitochondria anchoring. As the ambient viscosity in...     

A selective and sensitive off–on probe for palladium and its application for living cell imaging

A new rhodamine B derivative T1 has been rationally synthesized and displayed selective Pd(Ⅱ)-amplified absorbance and fluorescence emission above 540 nm in methanol–water. Upon the addition of Pd(Ⅱ), the spirolactam ring was unfolded and a 1:1 metal-ligand complex formed, which can be used for ‘‘naked-eyes" detection. In addition, fluorescence imaging experiments of Pd~(2+) in HepG2 living cells showed its valuable application in biological systems.     

A highly sensitive “turn-on” fluorescent probe for bovine serum albumin protein detection and quantification based on AIE-active distyrylanthracene derivative

A sulfonated 9,10-distyrylanthracene derivative with aggregation-induced emission (AIE) property is designed and synthesized. It shows a highly sensitive and selective fluorescence enhancement property for bovine serum albumin (BSA) protein detection and quantification. Analysis on the interaction between the probe molecule and BSA reveals the essential role of the hydrophobic cavities of the protein folding structure.     

Composite Eu-MOF@CQDs “off & on” ratiometric luminescent probe for highly sensitive chiral detection of l-lysine and 2-methoxybenzaldehyde

The high amount of l-lysine can increase the potential risk of cardiovascular disease. Additionally, 2-methoxy benzaldehyde (2-MB) has high toxicity and can easily pollute the environment. In this work, carbon quantum dots (CQDs) can be encapsulated into Eu-BTB (H₃BTB = 1,3,5-tri(4-carboxyphenyl)benzene), forming the multi-emission composite material Eu-BTB@CQDs. It has two emissions peaks (617 nm for Eu and 470 nm for CQDs). Eu-BTB@CQDs can be applied as bi-functional ratiometric “off & on” luminescent sensor for l-lysine and 2-MB with high sensitivity and selectivity, the low limit of detection (LOD) for l-lysine is 3.68 µmol/L and for 2-MB is 0.54 µmol/L, respectively. Additionally, Eu-BTB@CQDs can quantitatively discriminate l-lysine in the mixed d- and l-lysine water solutions (five different concentrations ratio of l/d-lysine has been set) makes the chiral detection of l-lysine are more meaningful. On the other hand, Eu-BTB@CQDs also can detect 2-MB over 4-methoxybenzaldehyde (4-MB) with high selectivity. Further the detection of 2-MB and l-lysine in the lake water real samples with the reasonable recovery rate. Finally, the detection mechanisms for l-lysine and 2-MB were also investigated and discussed in detail.     

A highly selective HBT-based “turn-on” fluorescent probe for hydrazine detection and its application

As one of the important industrial chemicals, hydrazine (N₂H₄) can be inhaled through the skin, leading to many serious health issues. In this paper, we constructed a novel turn-on fluorescent probe HBTM for N₂H₄ detection based on ESIPT and ICT mechanism by incorporating the methyl dicyanvinyl group to 2-(2′-hydroxylphenyl) benzothiazole (HBT) fluorophore. The probe showed the following advantages: high sensitivity with detection limit of 2.9 × 10^?7 M, high selectivity over other related interfering species, wide linear range of 0–140 μM and pH value adaptation. Moreover, the probe could detect N₂H₄ on paper strips and image N₂H₄ in living cells.     

Highly selective two-photon fluorescent probe for imaging of nitric oxide in living cells简

A new two-photon fluorescent probe, ADNO, for nitric oxide （NO） based on intramolecular photoinduced electron transfer （PET） mechanism d/splays a rapid response to NO with a remarkable fluorescent enhancement in PBS buffer. The excellent chemoselectivity of ADNO for NO over other ROS/RNS （reactive oxygen species or nitrogen species） and common metal ions was observed. Moreover, ADNO has been successfully applied in fluorescence imaging of NO of living cells using both one-photon microscopy （OPM） and two-~hoton microscopy （TPM）,     

Target-activated and ratiometric photochromic probe for “double-check” detection of toxic thiols in live cells

Photochromic molecules can achieve reversible isomerization upon alternate light irradiations, which offers a great opportunity to improve the precision of analytes detection and imaging in complicated biological environments. Previous reported photochromic probe exhibited only mono-color switching and an initially fluorescence-ON state that may cause high background signal and impose an adverse impact on the desired sensing precision. To overcome this set-back, we developed a novel photochromic probe with an analyte-activation mode for ratiometric sensing of toxic thiols in both real water samples and live cells. The dynamic dual-fluorescence signal is released only after the fast and selective cleavage of the 2,4-dinitrophenyl sulfonate by the targeted thiophenol derivatives. Consequently, a double-check with synchronized dual-fluorescence blinking for analyte detection is successfully employed upon alternate light triggers with rapid response(k=7.2×10~(-2) s~(-1)), high sensitivity(LOD=6.1 nM) as well as selectivity of thiophenol derivatives over other common thiol species(e.g., GSH, Cys and Hcy). The photochromic probe was successfully introduced to the fast and on-site detection of highly toxic thiophenols in real waste water samples. Moreover, by using confocal laser-scanning microscopy(CLSM) and flow cytometric analysis, the potential applications of this ratiometric photochromic probe for trace toxic thiol sensing in live cells are examined.     

Highly sensitive and selective “off-on” fluorescent sensing platform for ClO− in water based on silicon quantum dots coupled with nanosilver

Analytical and Bioanalytical Chemistry - We present a new “off-on” fluorescence probe for detecting hypochlorite (ClO−) based on silicon quantum dots coupled with silver...     

Ruthenium Nanoparticles Loaded on Carbon as Effective Catalyst for Highly Selective Hydrogenation of 4,4′-Methylenedianiline

Supported Ru-based catalysts, prepared by a surfactant-stabilized colloidal method, exhibited a good selectivity to bis(4-aminocyclohexyl)methane via the hydrogenation of 4,4′-methylenedianiline. Transmission electron microscopy(TEM) and X-ray diffraction(XRD) characterization showed Ru nanoparticles were well-dispersed on activated carbon, leading to the high activity and selectivity to the product.     

Study on Highly Active Catalysts and a Once—Through Process for Methanol Synthesis from Syngas

Highly active CNT-promoted co-precipitated Cu-ZnO-Al2O3 catalysts, symbolized as CuiZnj;Alfc-a;%CNTs, were prepared, and their catalytic activity for once-through methanol synthesis from syngas was investigated. The results illustrated that, under the reaction conditions (at 493 K, 5.0 MPa, the volume ratio of H2/CO/CO2/N2= 62/30/5/3, GHSV= 4000 h-1), the observed single-pass CO-conversion and methanol-STY over a Cu6Zn3Al1-12.5%CNTs catalyst reached 64% and 1210 mg/(h-g), which was about 68% and 66% higher than those (38% and 730 mg/(h-g)) over the corresponding CNT-free catalyst, Cu6Zn3Al1, respectively. The characteristic studies of the catalysts revealed that appropriate incorporation of a minor amount of the CNTs into the CuiZnjAlk brought about little change in the apparent activation energy of the methanol synthesis reaction, however, led to a considerable increase in the catalyst's active Cu surface area and pronouncedly enhanced the stationary-state concentration of active hydrogen-adspecies on     

Highly selective catalysts for liquid-phase hydrogenation of substituted alkynes based on Pd—Cu bimetallic nanoparticles

Catalytic properties of Pd—Cu bimetallic catalysts supported on SiO₂ and Al₂O₃ were studied in a model reaction of selective hydrogenation of diphenylacetylene. Application of PdCu₂(AcO)₆ heterobimetallic acetate complex as a precursor made it possible to obtain homogeneous Pd—Cu bimetallic nanoparticles. This result was supported by the data of IR spectroscopy of adsorbed CO. The Pd-Cu catalysts showed considerably higher selectivity than monometallic samples. Moreover, the introduction of copper decreases the hydrogenation rate of diphenylethylene (DPE) to diphenylethane. As a result, the maximum yield of the target product, DPE, increased from 78 to 93% in the presence of Pd—Cu catalysts.     

PdRu Nanoparticles Supported on Functionalized Titanium Carbide—a Highly Efficient Catalyst for Formic Acid Electro-Oxidation

Russian Journal of Electrochemistry - In this study, a simple strategy for the synthesis of PdRu nanoparticles, supported on titanium carbide functionalized by amino-rich cationic polymer...     

A new BODIPY-based fluorescent “turn-on” probe for highly selective and rapid detection of mercury ions

A new fluorescent sensor based on the BODIPY fluorophore and the carboxyl-thiol metal bonding receptor for Hg²⁺ was designed and synthesized. The sensor is highly selective for Hg²⁺ (about 630-fold fluorescence enhancement) over relevant competing metal ions, sensitive to ppb levels of Hg²⁺ (with detection limit of 5.7?nM), and fast response toward Hg²⁺ (within 30?s) in aqueous solution.     

Ion recognition by 1,2,3-triazole moieties synthesized via “click chemistry”

1,2,3-Triazole-based ligands obtained through copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) have been exploited in vast array of research domains owing to the stitching of simpler molecules through a needle of Cu(I) catalyst. The numerous reports on ion(s) detection capabilities of synthesized 1,4-disubstituted 1,2,3-triazole ligands using absorption and fluorescence spectroscopy are accessible. This review enlists substituted 1,2,3-triazole-based sensor probes, since 2010, synthesized selectively by CuAAC, having the ability to sense either a single ion or multiple ions under specific set of conditions along with their detection limits. The review also apprehends the different techniques and sensing mechanisms involved in the detection of ions by chemosensor probes.