Synthesis and Characterization of Diketopyrrolopyrrole-Based Aggregation-Induced Emission Nanoparticles for Bioimaging

Conventional fluorescent dyes have the property of decreasing fluorescence due to aggregation-caused quenching effects at high concentrations, whereas aggregation-induced emission dyes have the property of increasing fluorescence as they aggregate with each other. In this study, diketopyrrolopyrrole-based long-wavelength aggregation-induced emission dyes were used to prepare biocompatible nanoparticles suitable for bioimaging. Aggregation-induced emission nanoparticles with the best morphology and photoluminescence intensity were obtained through a fast, simple preparation method using an ultrasonicator. The optimally prepared nanoparticles from 3,6-bis(4-((E)-4-(bis(40-(1,2,2-triphenylvinyl)-[1,10-biphenyl]-4-yl)amino)styryl)phenyl)-2,5-dihexyl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (DP-R2) with two functional groups having aggregation-induced emission properties and additional donating groups at the end of the triphenylamine groups were considered to have the greatest potential as a fluorescent probe for bioimaging. Furthermore, it was found that the tendency for aggregation-induced emission, which was apparent for the dye itself, became much more marked after the dyes were incorporated within nanoparticles. While the photoluminescence intensities of the dyes were observed to decrease rapidly over time, the prepared nanoparticles encapsulated within the biocompatible polymers maintained their initial optical properties very well. Lastly, when the cell viability test was conducted, excellent biocompatibility was demonstrated for each of the prepared nanoparticles.     

Dimerization of Organic Dyes on Luminescent Gold Nanoparticles for Ratiometric pH Sensing

Synergistic effects arising from the conjugation of organic dyes onto non‐luminescent metal nanoparticles (NPs) have greatly broadened their applications in both imaging and sensing. Herein, we report that conjugation of a well‐known pH‐insensitive dye, tetramethyl‐rhodamine (TAMRA), to pH‐insensitive luminescent gold nanoparticles (AuNPs) can lead to an ultrasmall nanoindicator that can fluorescently report local pH in a ratiometric way. Such synergy originated from the dimerization of TAMRA on AuNPs, of which geometry was very sensitive to surface charges of the AuNPs and can be reversely modulated through protonation of surrounding glutathione ligands. Not limited to pH‐insensitive dyes, this pH‐dependent dimerization can also enhance the pH sensitivity of fluorescein, a well‐known pH‐sensitive dye, within a larger pH range, opening up a new pathway to design ultrasmall fluorescent ratiometric nanoindicators with tunable wavelengths and pH response ranges.     

有机染料阳离子修饰的金属有机框架材料的倍频效应及双光子活性

选取易于制备的MOFs(ZJU-28)为功能性载体,将具有非线性光学性质的2种阳离子染料DB和TM与载体孔道中的二甲胺阳离子进行交换,实现阳离子型有机荧光离子在金属有机框架中定向组装,获得具有非线性光学效应的复合材料。强极性染料离子DB和TM在晶体孔道中的定向排布,改变了原有MOFs晶体的中心对称性。通过共聚焦显微镜观察到,原来不具有非线性光学效应的ZJU-28晶体通过有机阳离子交换后,形成的DB@ZJU-28和TM@ZJU-28复合材料具有较强的倍频效应和双光子荧光。     

有机染料阳离子修饰的金属有机框架材料的倍频效应及双光子活性

选取易于制备的MOFs（ZJU-28）为功能性载体,将具有非线性光学性质的2种阳离子染料DB和TM与载体孔道中的二甲胺阳离子进行交换,实现阳离子型有机荧光离子在金属有机框架中定向组装,获得具有非线性光学效应的复合材料。强极性染料离子DB和TM在晶体孔道中的定向排布,改变了原有MOFs晶体的中心对称性。通过共聚焦显微镜观察到,原来不具有非线性光学效应的ZJU-28晶体通过有机阳离子交换后,形成的DB@ZJU-28和TM@ZJU-28复合材料具有较强的倍频效应和双光子荧光。     

表面修饰Ag_2S纳米微粒的制备及其量子尺寸效应研究

采用同阳离子共沉淀法制备了DDP修饰的Ag2 S纳米微粒 ,其紫外—可见吸收光谱和荧光光谱表明DDP修饰的Ag2 S纳米微粒具有显著的量子尺寸效应 ,粒子尺寸分布较窄 ,粒子表面存在多种表面态能级。     

Precursor and Solvent Effects in the Nonhydrolytic Synthesis of Complex Oxide Nanoparticles for Bioimaging Applications by the Ether Elimination (Bradley) Reaction

Investigation of the solvent and alkoxide precursor effect on the nonhydrolytic sol–gel synthesis of oxide nanoparticles by means of an ether elimination (Bradley) reaction indicates that the best crystallinity of the resulting oxide particles is achieved on application of aprotic ketone solvents, such as acetophenone, and of smallest possible alkoxide groups. The size of the produced primary particles is always about 5 nm caused by intrinsic mechanisms of their formation. The produced particles, possessing the composition of natural highly insoluble minerals, are biocompatible. Optical characteristics of the perovskite complex oxide nanoparticles can easily be controlled through doping with rare earth cations; for example, by Eu³⁺. They can be targeted through surface modification by anchoring the directing biomolecules through a phosphate or phosphonate moiety. Testing of the distribution of Eu‐doped BaTiO₃ particles, modified with ethylphosphonic acid, demonstrates their facile uptake by the plants with active fluid transport, resulting finally in their enhanced concentration within the cell membranes.     

Sunlight-Active BiOI Photocatalyst as an Efficient Adsorbent for the Removal of Organic Dyes and Antibiotics from Aqueous Solutions

A bismuth oxyiodide (BiOI) photocatalyst with excellent sunlight-driven performance was synthesized by a solvothermal route without the addition of surfactants or capping agents. The prepared photocatalyst exhibited a tetragonal phase with an energy band gap of 2.15 eV. The efficiency of the photocatalyst was elucidated by monitoring the photodegradation of organic dyes and antibiotics. The BiOI photocatalyst provided a 95% removal of norfloxacin (NOR) antibiotics under visible light illumination. Interestingly, the complete removal of Rhodamine B (RhB) dye was achieved after 80 min of natural sunlight irradiation. The photodegradation reaction followed the first-order reaction. Both photo-generated holes and electrons play vital roles in the photodegradation of the pollutant. The BiOI photocatalyst remains stable and still shows a high efficiency even after the fifth run. This confirms the great cycling ability and high structural stability of the photocatalyst. The prepared BiOI catalyst, with a high surface area of 118 m² g⁻¹, can act as an excellent adsorbent as well. The synergistic effect based on both adsorption and photocatalysis is a key factor in achieving a very high removal efficiency. The photoactivity under sunlight is higher than that observed under visible light, supporting the practical use of the BiOI photocatalyst for the removal of organic pollutants in wastewater through the utilization of abundant solar energy.     

Water-soluble AIE-active Fluorescent Organic Nanoparticles: Design,Preparation and Application for Specific Detection of Cyanide in Water and Food Samples

A dilactosyl-dicyanovinyl-functionalized tetraphenylethene ( TPELC ) was designed, synthesized and used for ratiometric sensing of cyanide. TPELC was comprised of three moieties (tetraphenylethylene, dicyanovinyl group and lactose unit) in one molecule, making TPELC water-soluble and aggregation-induced emission (AIE)-active and selectively reactive to cyanide. Compared with other reported fluorescent probes containing dicyanovinyl group, TPELC is the first AIE luminogen to be assembled as fluorescent organic nanoparticles (FONs) for sensing of cyanide in water without the use of surfactant or the help of organic solvents based on the nucleophilic addition reaction. The detection mechanism was verified by liquid chromatograph mass spectrometry experiments and by protonation of cyanide to reduce the nucleophilicity of cyanide. In addition, TPELC was used for detection of the cyanide content of food samples and test strips were developed to simplify the detection procedure.     

Highly Luminescent and Water‐Soluble Two‐Dimensional Supramolecular Organic Framework: All‐Organic Photosensitizer Template for Visible‐Light‐Driven Hydrogen Evolution from Water

A highly fluorescent (Φ_F=0.60) and water‐soluble two‐dimensional (2D) honeycomb‐shaped supramolecular organic framework (SOF) was successfully synthesized in pure aqueous solution via self‐assembly of novel cyanostilbene‐functionalized trilateral guest molecules and cucurbit[8]uril hosts. The size of this fluorescent 2D SOF was >500 nm in diameter, 1.7 nm in thickness, and 3.9 nm in the honeycomb pore diameter. This 2D SOF holds potential as a new all‐organic photosensitizer template for photocatalytic H₂ evolution from pure water.     

Removal of Tannic Acid Stabilizes CuO Nanoparticles from Aqueous Media by PAFC: Effect of Process Conditions and Water Chemistry

The increased utilization of CuO nanoparticles (CuO NPs) in various fields has raised concerns about their discharge into water containing a wide range of organic ligands. Moreover, the adsorption of these ligands can stabilize the CuO NPs in drinking water treatment plants. Thus, their removal from potable water is important to mitigate the risk to humans. The present study explored the efficacy of the coagulation–sedimentation (C/S) process for the removal of tannic acid (TA)-stabilized CuO NPs using polyaluminum ferric chloride (PAFC) as a coagulant. Moreover, the influence of process conditions (stirring speed) and water chemistry (i.e., pH and ionic strength (IS)) were also investigated to determine their impact on removal. The results showed that stirring speed in the reaction phase significantly affected the removal due to increased flocculation compared with stirring speed in the mixing phase. In addition, pH and IS affect the colloidal stability and removal efficiency of CuO NPs. A relatively better removal performance (<99%) of CuO NPs was found at lower coagulant dosage in the pH range 6–8. The addition of organic ligands reversed the surface charge potential and enhanced the colloidal stability of CuO NPs, resulting in the destabilization of TA-CuO NPs, thereby reducing the optimum PAFC dosage for removal. By contrast, the IS above the critical coagulation concentration decreased the removal efficiency due to inhibition of the ionic activity of PAFC hydrolysate in the aqueous environment. Fourier transform infrared findings of TA-CuO NPs composite flocs suggest that the primary removal mechanism might be mediated via the combined effect of neutralization, complexation as well as adsorption.     

Metal@COFs: Covalent Organic Frameworks as Templates for Pd Nanoparticles and Hydrogen Storage Properties of Pd@COF‐102 Hybrid Material

Three‐dimensional covalent organic frameworks (COFs) have been demonstrated as a new class of templates for nanoparticles. Photodecomposition of the [Pd(η³‐C₃H₅)(η⁵‐C₅H₅)]@COF‐102 inclusion compound (synthesized by a gas‐phase infiltration method) led to the formation of the Pd@COF‐102 hybrid material. Advanced electron microscopy techniques (including high‐angle annular dark‐field scanning transmission electron microscopy and electron tomography) along with other conventional characterization techniques unambiguously showed that highly monodisperse Pd nanoparticles ((2.4±0.5) nm) were evenly distributed inside the COF‐102 framework. The Pd@COF‐102 hybrid material is a rare example of a metal‐nanoparticle‐loaded porous crystalline material with a very narrow size distribution without any larger agglomerates even at high loadings (30 wt %). Two samples with moderate Pd content (3.5 and 9.5 wt %) were used to study the hydrogen storage properties of the metal‐decorated COF surface. The uptakes at room temperature from these samples were higher than those of similar systems such as Pd@metal–organic frameworks (MOFs). The studies show that the H₂ capacities were enhanced by a factor of 2–3 through Pd impregnation on COF‐102 at room temperature and 20 bar. This remarkable enhancement is not just due to Pd hydride formation and can be mainly ascribed to hydrogenation of residual organic compounds, such as bicyclopentadiene. The significantly higher reversible hydrogen storage capacity that comes from decomposed products of the employed organometallic Pd precursor suggests that this discovery may be relevant to the discussion of the spillover phenomenon in metal/MOFs and related systems.     

Effective and Selective Catalysts for Cinnamaldehyde Hydrogenation: Hydrophobic Hybrids of Metal–Organic Frameworks,Metal Nanoparticles,and Micro‐ and Mesoporous Polymers

Metal–organic frameworks (MOFs) as selectivity regulators for catalytic reactions have attracted much attention, especially MOFs and metal nanoparticle (NP) shelled structures, e.g., MOFs@NPs@MOFs. Nevertheless, making hydrophilic MOF shells for gathering hydrophobic reactants is challenging. Described here is a new and viable approach employing conjugated micro‐ and mesoporous polymers with iron(III) porphyrin (FeP‐CMPs) as a new shell to fabricate MIL‐101@Pt@FeP‐CMP. It is not only hydrophobic and porous for enriching reactants, but also possesses iron sites to activate C=O bonds, thereby regulating the selectivity for cinnamyl alcohol in the hydrogenation of cinnamaldehyde. Interestingly, MIL‐101@Pt@FeP‐CMP^sponge can achieve a high turnover frequency ( 1516.1 h^?1), with 97.3 % selectivity for cinnamyl alcohol at 97.6 % conversion.     

Water‐soluble Glucosamine‐coated AIE‐Active Fluorescent Organic Nanoparticles: Design,Synthesis and Assembly for Specific Detection of Heparin Based on Carbohydrate–Carbohydrate Interactions

Two water‐soluble carbohydrate‐coated AIE‐activate fluorescent organic nanoparticles TPE3G and TPE4G were designed and synthesized for the detection of heparin. Different from the reported strategy, we not only utilized the general detection mechanism of electrostatic interactions, but also introduced the concept of carbohydrate‐carbohydrate interactions (CCIs) to enrich the detection mechanism of heparin. TPE3G can serve as an efficient “turn‐on” probe with higher selectivity towards heparin than TPE4G . TEM studies revealed that the micro‐aggregated TPE3G was encapsulated with the heparin chain to form a complex self‐assemblied composite and emits strong fluorescence. It is believed that the results illustrated in this study provide a novel strategy based on CCls to design water‐soluble and more efficient bio‐probes for various biological and clinical applications.     

A Versatile CuII Metal–Organic Framework Exhibiting High Gas Storage Capacity with Selectivity for CO2: Conversion of CO2 to Cyclic Carbonate and Other Catalytic Abilities

A linear tetracarboxylic acid ligand, H₄L, with a pendent amine moiety solvothermally forms two isostructural metal–organic frameworks (MOFs) L_M (M=Zn^II, Cu^II). Framework L_Cu can also be obtained from L_Zn by post‐ synthetic metathesis without losing crystallinity. Compared with L_Zn , the L_Cu framework exhibits high thermal stability and allows removal of guest solvent and metal‐bound water molecules to afford the highly porous, L_Cu′ . At 77 K, L_Cu′ absorbs 2.57 wt % of H₂ at 1 bar, which increases significantly to 4.67 wt % at 36 bar. The framework absorbs substantially high amounts of methane (238.38 cm³ g^?1, 17.03 wt %) at 303 K and 60 bar. The CH₄ absorption at 303 K gives a total volumetric capacity of 166 cm³ (STP) cm^?3 at 35 bar (223.25 cm³ g^?1, 15.95 wt %). Interestingly, the NH₂ groups in the linker, which decorate the channel surface, allow a remarkable 39.0 wt % of CO₂ to be absorbed at 1 bar and 273 K, which comes within the dominion of the most famous MOFs for CO₂ absorption. Also, L_Cu′ shows pronounced selectivity for CO₂ absorption over CH₄, N₂, and H₂ at 273 K. The absorbed CO₂ can be converted to value‐added cyclic carbonates under relatively mild reaction conditions (20 bar, 120 °C). Finally, L_Cu′ is found to be an excellent heterogeneous catalyst in regioselective 1,3‐dipolar cycloaddition reactions (“click” reactions) and provides an efficient, economic route for the one‐pot synthesis of structurally divergent propargylamines through three‐component coupling of alkynes, amines, and aldehydes.     

Summary of ISO/TC 201 Standard: XIX ISO 17331:2004—Surface chemical analysis—Chemical methods for the collection of elements from the surface of silicon‐wafer working reference materials and their determination by total‐reflection x‐ray fluorescence (TXRF) spectroscopy

This international standard specifies chemical methods for the collection of iron and/or nickel from the surface of silicon‐wafer working reference materials by the vapour‐phase decomposition method or the direct acid droplet decomposition method. The determination of the elements collected may be carried out by total‐reflection x‐ray fluorescence spectroscopy, as well as by graphite‐furnace atomic absorption spectroscopy or inductively coupled plasma mass spectroscopy. This international standard applies to iron and/or nickel atomic surface densities from 6 × 10⁹ to 5 × 10¹¹ atoms cm^?2. Copyright © 2005 John Wiley & Sons, Ltd.