选择性响应Cu~(2+)、Ag~+及阴离子的菲咯啉-水杨醛荧光探针

在乙酸酐中用2,9-二甲基-1,10-菲咯啉与水杨醛缩合反应得到2,2′-(1E,1′E)-2,2′-(1,10-菲咯啉-2,9-二基)双(乙烯-2,1-二基)双(2,1-亚苯基)二乙酸酯(探针1);再将其进一步水解得到2,2′-(1E,1′E)-2,2′-(1,10-菲咯啉-2,9-二基)双(乙烯-2,1-二基)二苯酚(探针2)。经1H NMR、13C NMR、IR、MS表征,探针化合物为大共轭结构,发光性能良好。两种探针分别表现出对Cu2+、Ag+不同的荧光猝灭作用,探针2还能识别阴离子F-和AcO-,具有双功能离子检测性能。光谱滴定、等温滴定量热及质谱等测定了配合物组成、作用常数及热力学参数,探针与金属离子的配合为放热反应,作用比为2∶1。     

季铵盐类阳离子单体的合成工艺研究进展

对季铵盐类阳离子单体的合成工艺及结构改性研究进展进行了综述。基于季铵盐类阳离子单体的基本结构与性质,从合成反应基本历程及代表性制备工艺方法出发,介绍了二烯丙基季铵盐类、丙烯酰胺烷基季铵盐类和丙烯酰胺烷基季铵盐类三类最为重要的季铵盐阳离子单体的合成、聚合及结构改性最新研究进展,指出了已有研究工作的特色与不足,并认为开发高质量丙烯酰胺烷基季铵盐类单体及聚合物产品以及高纯度质量稳定的阳离子单体制备新工艺是今后应努力的方向。     

A Layered Cationic Aluminum Oxyhydroxide as a Highly Efficient and Selective Trap for Heavy Metal Oxyanions

Cationic framework materials, especially pure inorganic cationic frameworks that can efficiently and selectively capture harmful heavy metal oxyanions from aqueous solution are highly desired yet scarcely reported. Herein, we report the discovery of a 2D cationic aluminum oxyhydroxide, JU-111, which sets a new benchmark for heavy metal oxyanion sorbents, especially for Cr^VI. Its structure was solved based on 3D electron diffraction tomography data. JU-111 shows fast sorption kinetics (ca. 20 min), high capture capacity (105.4 mg g⁻¹), and broad working pH range (3–10) toward Cr^VI oxyanions. Unlike layered double hydroxides (LDHs), which are poorly selective in the presence of CO₃²⁻, JU-111 retains excellent selectivity for Cr^VI even under a large excess of CO₃²⁻. These superior features coupled with the ultra-low cost and environmentally benign nature make JU-111 a promising candidate for toxic metal oxyanion remediation as well as other potential applications.     

Orthogonal Cationic and Radical RAFT Polymerizations to Prepare Bottlebrush Polymers

An orthogonal combination of cationic and radical RAFT polymerizations is used to synthesize bottlebrush polymers using two distinct RAFT agents. Selective consumption of the first RAFT agent is used to control the cationic RAFT polymerization of a vinyl ether monomer bearing a secondary dormant RAFT agent, which subsequently allows side‐chain polymers to be grafted from the pendant RAFT agent by a radical‐mediated RAFT polymerization of a different monomer, thus completing the synthesis of bottlebrush polymers. The high efficiency and selectivity of the cationic and radical RAFT polymerizations allow both polymerizations to be conducted in one‐pot tandem without intermediate purification.     

Optimization and detailed stability study on Pb doped ceria nanocubes for enhanced photodegradation of several anionic and cationic organic pollutants

A series of Pb doped CeO₂ nanocubes with seven different Pb loadings (2–12 mol%) were synthesized via modified hydrothermal technique. The prepared samples were characterized by XRD, XPS, FT-IR, TGA, SEM, HR-TEM, EDS and UV–Vis DRS analysis. According to XRD analysis, the crystalline structure of synthesized pure CeO₂ and Pb-doped CeO₂ samples are cubic structure. The ceria nanocubes showed an increase in amount of oxygen vacancies with increasing the dopant concentrations. When the doping level of Pb is 6 mol%, the optical band gap of Pb-CeO₂ is smaller than that of pure CeO₂ nanocubes. The HR-TEM results confirms the cubic structure of 6% Pb-CeO₂ with average crystallite size of about 15 nm. The photocatalytic ability of Pb-CeO₂ catalysts were studied by degrading several anionic and cationic organic pollutants like methylene blue (MB), methylene orange (MO), methylene red (MR), rhodamine B (RhB), reactive blue 160 (RB160), salicylic acid (SA), coumarin and phenol. The 6% Pb-CeO₂ nanocubes shows better photocatalytic performance against anionic dyes especially for MB. To find the optimum condition for better photocatalytic performance of 6% Pb-CeO₂ nanocubes, the photocatalytic process was conducted in different initial reaction conditions like reaction temperature, catalytic dosage, dye concentration and pH of the reaction solution. The stability and recyclability of 6% Pb-CeO₂ photocatalyst was studied by XRD, FT-IR and EDS analysis after 5 cycles of MB degradation. The hydroxyl radical estimation and trapping experiments were conducted to observe the photocatalytic mechanism process in 6% Pb-CeO₂ nanocubes. The perfect doping concentration for better organic pollutant degradation by Pb-CeO₂ is found to be 6 mol% of Pb.     

The synthesis and cationic polymerization behavior of ambifunctional monomers

The synthesis of a novel series of ambifunctional monomers containing cationically polymerizable vinyl and 1-propenyl ether or 1-butenyl ether groups in the same molecule has been carried out. Studies of the onium salt-induced photopolymerizations of these monomers indicate that both functional groups are highly reactive and that they undergo extensive copolymerization. © 1996 John Wiley & Sons, Inc.     

The use of carbon black-supported sulfuric acid to initiate the cationic polymerization of cyclic ketene acetals

Stable polymers were made by the cationically initiated 1,2-polymerization of cyclic ketene acetals employing heterogeneous, activated carbon-supported sulfuric acid catalysts. A methodology has been established for the preparation of the carbon black of different acidic strengths. By adjusting either the acid strength or the amount of carbon black used, cyclic ketene acetals with different activities can be polymerized efficiently to form stable high molecular weight polymers. This methodology will be a useful tool for polymerization, copolymerization, and studies of the relative reactivities of the cyclic ketene acetals. The polymer structures were determined by FTIR, ¹³C-NMR, and ¹H-NMR studies. © 1996 John Wiley & Sons, Inc.     

Microstructure of polymers obtained by cationic polymerization of endo-dicyclopentadiene

endo-Dicyclopentadiene (DCPD) was polymerized by various cationic initiating systems in different solvents. IR and ¹H NMR results show that four types of structural units are formed due to the corresponding addition modes: the addition on the norbornenic (NB) double bond generates unit I and rearranged unit II, while the addition on the cyclopentenic (CP) double bond produces unit III and rearranged unit IV. The reaction medium has a stronger effect on the microstructure of the polymer (PDCPD) than initiating systems. The polymers prepared in toluene and n-hexane contain all four structural units, while the polymer produced in methylene chloride is composed of structural units II and IV. © 1996 John Wiley & Sons, Inc.     

Kinetics of cationic photopolymerizations of divinyl ethers characterized using in situ Raman spectroscopy

In situ Raman spectroscopy experiments were used to determine effective kinetic propagation constants for a series of unsteady-state divinyl ether polymerizations at different isothermal temperatures and light intensities. Raman spectroscopy was found to be ideally suited for monitoring cationic photopolymerizations because the technique allows isothermal experiments to be performed with excellent time resolution and allows several spectral features to be observed simultaneously. In addition, the Raman experiments provided direct information about the vinyl bond concentration in situ as the reaction takes place. For these cationic photopolymerizations, the reaction rate and limiting conversion were both found to increase as the reaction temperature was increased. At all temperatures, the profile for the propagation rate constant, k_p, exhibited a dramatic increase at the start of the reaction, plateaued at a value between 10 and 40 l/mol s (depending upon temperature), and then decreased as the reaction reached a limiting conversion due to trapping of the active centers. Finally, the overall activation energy for polymerization was found to be 25.1 ± 6.1 kJ/mol. © 1996 John Wiley & Sons, Inc.