Gold-Catalyzed 1,2-Aryl Shift and Double Alkyne Benzannulation

The tandem intramolecular hydroarylation of alkynes accompanied by a 1,2-aryl shift is described. Harnessing the unique electron-rich character of 1,4-dihydropyrrolo[3,2-b]pyrrole scaffold, we demonstrate that the hydroarylation of alkynes proceeds at the already occupied positions 2 and 5 leading to a 1,2-aryl shift. Remarkably, the reaction proceeds only in the presence of cationic gold catalyst, and it leads to heretofore unknown π-expanded, centrosymmetric pyrrolo[3,2-b]pyrroles. The utility is verified in the preparation of 13 products that bear six conjugated rings. The observed compatibility with various functional groups allows for increased tunability with regard to the photophysical properties as well as providing sites for further functionalization. Computational studies of the reaction mechanism revealed that the formation of the six-membered rings accompanied with a 1,2-aryl shift is both kinetically and thermodynamically favourable over plausible formation of products containing 7-membered rings. Steady-state UV/Visible spectroscopy reveals that upon photoexcitation, the prepared S-shaped N-doped nanographenes undergo mostly radiative relaxation leading to large fluorescence quantum yields. Their optical properties are rationalized through time-dependent density functional theory calculations. We anticipate that this chemistry will empower the creation of new materials with various functionalities.     

A critical review of hazardous waste generation from textile industries and associated ecological impacts

Among many industries, the textile industry is the oldest industry of human civilization. Cloth is the second most important human need after food. Textile processing includes several steps in which wet processing is the most important. As wet processing involves an extensive amount of water and chemicals, an enormous volume of textile effluent generates during wet processing. Textile effluents is disposed of on bare land or on water bodies, which causes soil and water contamination. Improper disposal of textile effluents causes severe soil and water contamination. Textile effluents contain dyes, heavy metals, inorganic salts, surfactants, organic contaminants, oil, and grease. Textile effluents cause contamination in water bodies. The colour present in effluents hinders the photosynthesis of aquatic plants. Inorganic salts cause the degradation of water quality and soil excellence. Heavy metals enter the food chain and cause severe health impacts on human life. Various physical, chemical, bailogical and hybrid methods are used to treat textile effluents. Textile processing has been explained in brief in this study. The current research deals with different textile processing steps, various pollutants generated in textile processing and their ecotoxicity, various ecological crises associated with textile processing, and numerous treatment methods for the remediation of textile effluents.     

CuCl-catalyzed aerobic oxidative reaction of primary aromatic amines

The oxidations of primary aromatic amines were investigated. Cuprous chloride-air system can catalyze the oxidation of primary aromatic amines to azo derivatives, anils, and/or quinone anils. The experimental procedure is simple and the products could be easily isolated in high yields.     

Applicability of waste materials--bottom ash and deoiled soya--as adsorbents for the removal and recovery of a hazardous dye, brilliant green

Deoiled soya, an agricultural waste material, and bottom ash, a waste of power plants, have been successfully used for the removal and recovery of the hazardous water-soluble dye brilliant green from water. To remove the dye from water, batch adsorption studies have been carried out by observing the effects of pH, concentration, amounts of adsorbents, size of adsorbent particles, etc. Attempts have also been made to monitor the adsorption process through Langmuir, Freundlich, Tempkin, and D-R adsorption isotherm models. Relevant thermodynamic parameters have also been calculated from these models. The adsorption process has been found endothermic and feasible at all the temperatures. The kinetics of the adsorption was also recorded and indicates pseudo-second-order kinetics in both cases. Kinetic operations also reveal the involvement of a film diffusion mechanism for the deoiled soya adsorption at all the temperatures, while bottom ash undergoes through a particle diffusion mechanism at only 30 °C and at higher temperatures a film diffusion mechanism operates. Bulk removal of the dye has been carried out through column studies for both adsorbents. Attempts have also been made to recover the dye from exhausted columns by eluting sulfuric acid of pH 3.     

Determination of pyridine-2-azo-p-dimethylaniline acidity constants by spectra resolution methodology

The influence of acidity upon the pyridine-2-azo-p-dimethylaniline (PADA) absorption spectrum has been studied. The obtained results allowed us to calculate the acidity constants of PADA. The spectra resolution method has been used to determinate the constants. The absorption spectrum was decomposed in two sub-bands for the neutral form of the indicator, one for the monoprotonated molecule and another more for the diprotonated structure. The quantitative analysis of relative areas variation with the medium acidity allows us to obtain the equilibrium constants of PADA prolongation. The obtained values are in good agreement with the values reported in the literature.     

A novel fluorescent probe derived from isophorone and its application in imaging in vivo hypoxia

Herein, an isophorone-derived fluorescent probe, ARP, was developed to realize the imaging of in vivo hypoxia under the catalysis of the typical enzyme AzoR. Under the excitation at 456 nm, the detecting system with ARP could exhibit a red emission signal at 638 nm. ARP indicated advantages including high sensitivity (LOD = 0.37 Eq), high selectivity, anti-interference ability and wide pH adaption (3.0–12.0). Moreover, ARP could image the aggravation of the hypoxia in both the incubating oxygen percentage scale and the time scale in living cells. The AzoR-activated mechanism was convinced by the experimental result of adding inhibitors and illustrated by the molecular docking simulation. ARP could co-locate with the commercial dyes in the endoplasmic reticulum (ER), lysosomes, and mitochondria, which meant that ARP might be sensitive to the occurrence of the oxidation-reduction process or the passage through the intracellular membranes. Further, ARP achieved the imaging of hypoxia in both mice tumor model as well as tying model. ARP could distinguish the tumor site or the tied-up position according to the hypoxia extent. Therefore, this work raised a new trial for the imaging of the hypoxia, and might be helpful in future designs of more pragmatic fluorescent implements.     

结肠靶向偶氮高分子的合成及其体外降解性能

以二环己基碳酰亚胺/N,N-二甲基氨基吡啶为偶联剂,将结肠前体药物5,5′-偶氮二水杨酸(奥沙拉秦)与生物相容的聚乙二醇缩聚,制备得到主链含偶氮键的聚乙二醇-奥沙拉秦(PEO-OLZ)缩聚物.研究表明,改变聚乙二醇链段的分子量,可以方便地调节偶氮缩聚合物的亲水性和生物降解性能.在动物盲肠液中所含的偶氮还原酶的作用下,PEO-OLZ缩聚物的偶氮键发生特异性降解,同时通过酯键的水解,释放出抗结肠炎药物5-氨基水杨酸.该类新型偶氮缩聚物可以作为结肠靶向聚合物前体药,亦可用作结肠定位控释的高分子载体.     

Development of an ultraperformance liquid chromatography method for improved determination of additives in polymeric materials

An analytical method for the simultaneous separation and quantitation of ten colorants and six antioxidants used as polymer additives has been developed by transferring chromatographic conditions from two independent HPLC methods to a single ultraperformance liquid chromatography system. An experimental design was carried out to achieve the best elution gradient for separation of all the studied compounds with the best possible peak resolution and in the shortest possible analysis time. The new method gives good values for the analytical quality parameters evaluated.     

Improving the catalytic activity of magnetic Fe3O4/ZnO-CdO/reduced graphene oxide for ultrasonic degradation of the organic pollutants and the green oxidation of olefins

Magnetic Fe₃O₄/ZnO-CdO/reduced graphene oxide (MFZC/RGO) has been synthesized by simple hydrothermal method. The structure and morphology were investigated by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), Diffuse reflectance spectroscopy (DRS), Vibrating sample magnetometer (VSM), Raman and Fourier-transform infrared spectroscopy (FTIR). MFZC/RGO was applied as catalyst in degradation of methylene blue (MB), rhodamin B (RhB) and methylorange (MO) under ultrasonic irradiation. Based on the results, excellent degradation efficiencies of MB, RhB and MO (>99%) were achieved within 10, 20 and 20 min, respectively under oxygen flow. Moreover the catalytic property of MFZC/RGO was investigated in oxidation of styrene, α-methyl styrene, cyclohexene and cyclooctene under oxygen flow. In addition, MFZC/RGO can be easily collected and separated by an external magnet. The catalyst displayed negligible loss in activity and selectivity within several successive runs due to super paramagnetism.     

类黄酮型缩杂环酮化合物的合成研究

１前言黄酮类化合物广泛存在于植物体中,具有广泛的生物活性,其研究发展很快,特别是含氮黄酮类化合物具有抗癌、抗菌、冠状动脉扩张等作用［１］。但是,目前黄酮类药物仍然存在着两个问题,一是黄酮类化合物结构繁多,生物活性极其广泛,但作用强度普遍较弱;二是黄酮...