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991.
Shiyu Zuo Haiming Xu Wei Liao Lei Sun Donghui Han Jie Zan Binyang Zhang Dongya Li Dongsheng Xia 《应用有机金属化学》2018,32(9)
Acid‐treated g‐C3N4‐Cu2O was prepared by hydrothermal reduction followed by high temperature calcination and acid exfoliation. The structures and properties of as‐synthesized samples were characterized using a range of techniques, such as X‐ray photoelectron spectroscopy, scanning electron microscopy, Photoluminescence Spectroscopy and the Brunauer–Emmett–Teller (BET) theory. The photocatalytic activity was evaluated by measuring the photodegradation of methyl orange under visible‐light irradiation. Based on the results of TEM, XPS, EPR and other techniques, it was verified that a heterojunction was formed. The acid treatment process can increase the specific surface area to form abundant heterojunction interfaces as channels for photo‐generated carrier separation, thereby enhancing its light utilization and quantum efficiency. Results indicate that acid‐treated g‐C3N4‐Cu2O possesses a large specific surface area, which provides plentiful activated sites for heterojunctions to form; in addition, it showed a high visible light effect and the minimum charge‐transfer resistance. Furthermore, the g‐C3N4‐Cu2O material exhibits high levels of effectiveness and stability. Electron paramagnetic resonance and a series of radical trapping experiments demonstrate that the holes and ?O2? could be the main active species in methyl orange photodegradation. This work could provide new insights into the fabrication of composite materials as high‐performance photocatalysts, and facilitate their application in addressing environmental protection issues. 相似文献
992.
A new method for the production of p‐hydroquinone via a Pt/C‐catalyzed reduction of p‐benzoquinone is developed. Different from the conventional transfer hydrogenation reactions that usually use secondary alcohols such as isopropanol as the hydrogen source, in this work, it is unexpectedly found that cyclohexanone is a more effective hydrogen source than secondary alcohols, even cyclohexanol. This reaction affords acceptable yields of p‐hydroquinone with very high turnover number (1109) of the Pt/C catalyst. A mechanism of this interesting reaction is proposed on the basis of the results of a series of control experiments, GC–MS analysis as well as dynamic studies. 相似文献
993.
Yao Wen Shurui Cao Cunxian Xi Xianliang Li Lei Zhang Guomin Wang 《Analytical letters》2018,51(10):1479-1491
An analytical method for simultaneously determining 32 volatile organic compounds in mattress fabrics based on static headspace coupled to gas chromatography and mass spectrometry detection was established. Samples were cut into 5?×?5?mm small pieces and placed in a 20?mL headspace vial at 90° for 30?min. To achieve the optimum conditions for the analysis, several parameters including the heating temperature, heating time, sample weight, and injection time were investigated. The results demonstrated that the most important parameter influencing the sensitivity of the analysis was the heating temperature. The optimum method showed good linearities with correlation coefficients ranged from 0.9944 to 0.9998. The limits of detection and quantification for the target compounds were in the ranges of 0.004–0.032 and 0.013–0.099?µg/?g, respectively. The method was successfully applied to determine the volatile organic compounds in six categories of mattress fabrics. The results showed that some volatile organic compounds were found, such as naphthalene, hexadecane, and 1,4-diisopropylbenzene. Moreover, the concentrations of 32 volatile organic compounds decreased following the order of jute, terylene, polyester, velboa, nylon, and cotton samples in the study. These results indicated that the method is fast, accurate, and successful for determining volatile organic compounds in mattress fabrics. 相似文献
994.
A mild, efficient, and environmentally benign one-pot synthesis of functionalized chromeno[4,3-b]pyrrol-4(1H)-ones by a three-component domino reaction of 4-aminocoumarins, arylglyoxal monohydrates, and 1,3-dicarbonyl compounds in refluxing ethanol without the use of catalyst is reported. The present protocol features operational simplicity, short reaction time, good yields, and the absence of aqueous workup procedure and chromatographic separation. 相似文献
995.
High‐Temperature and High‐Energy‐Density Dipolar Glass Polymers Based on Sulfonylated Poly(2,6‐dimethyl‐1,4‐phenylene oxide) 下载免费PDF全文
Zhongbo Zhang Dr. David H. Wang Prof. Morton H. Litt Dr. Loon‐Seng Tan Prof. Lei Zhu 《Angewandte Chemie (International ed. in English)》2018,57(6):1528-1531
A new class of high‐temperature dipolar polymers based on sulfonylated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (SO2‐PPO) was synthesized by post‐polymer functionalization. Owing to the efficient rotation of highly polar methylsulfonyl side groups below the glass transition temperature (Tg≈220 °C), the dipolar polarization of these SO2‐PPOs was enhanced, and thus the dielectric constant was high. Consequently, the discharge energy density reached up to 22 J cm?3. Owing to its high Tg , the SO2‐PPO25 sample also exhibited a low dielectric loss. For example, the dissipation factor (tan δ) was 0.003, and the discharge efficiency at 800 MV m?1 was 92 %. Therefore, these dipolar glass polymers are promising for high‐temperature, high‐energy‐density, and low‐loss electrical energy storage applications. 相似文献
996.
Selective Oxidative [4+2] Imine/Alkene Annulation with H2 Liberation Induced by Photo‐Oxidation 下载免费PDF全文
Xia Hu Guoting Zhang Faxiang Bu Prof. Aiwen Lei 《Angewandte Chemie (International ed. in English)》2018,57(5):1286-1290
The oxidative [4+2] annulation reaction represents an elegant and versatile synthetic protocol for the construction of six‐membered heterocyclic compounds. Herein, a photoinduced oxidative [4+2] annulation of NH imines and alkenes was developed by utilizing a dual photoredox/cobaloxime catalytic system. Various multisubstituted 3,4‐dihydroisoquinolines can be obtained in good yields. This method is not only obviated the need of stiochiometric amounts of oxidants but also exhibited excellent atom economy by generating H2 as the only byproduct. Remarkably, high regioselectivity and trans diastereoselectivity can be achieved in this transformation even if the Z/E mixture of alkenes were employed. 相似文献
997.
Phase‐Transition Induced Conversion into a Photothermal Material: Quasi‐Metallic WO2.9 Nanorods for Solar Water Evaporation and Anticancer Photothermal Therapy 下载免费PDF全文
Lei Sun Zhuo Li Rui Su Yuanlin Wang Zhenglin Li Baosheng Du Prof. Ye Sun Prof. Pengfei Guan Prof. Flemming Besenbacher Prof. Miao Yu 《Angewandte Chemie (International ed. in English)》2018,57(33):10666-10671
Phase transition from WO3 to sub‐stoichiometric WO2.9 by a facile method has varied the typical semiconductor to be quasi‐metallic with a narrowed band gap and a shifted Femi energy to the conduction band, while maintaining a high crystallinity. The resultant WO2.9 nanorods possess a high total absorption capacity (ca. 90.6 %) over the whole solar spectrum as well as significant photothermal conversion capability, affording a conversion efficiency as high as around 86.9 % and a water evaporation efficiency of about 81 % upon solar light irradiation. Meanwhile, the promising potential of the nanorods for anticancer photothermal therapy have been also demonstrated, with a high photothermal conversion efficiency (ca. 44.9 %) upon single wavelength near‐infrared irradiation and a high tumor inhibition rate (ca. 98.5 %). This study may have opened up a feasible route to produce high‐performance photothermal materials from well‐developed oxides. 相似文献
998.
Transient‐Ligand‐Enabled ortho‐Arylation of Five‐Membered Heterocycles: Facile Access to Mechanochromic Materials 下载免费PDF全文
Bijin Li Kapileswar Seth Ben Niu Lei Pan Huiwen Yang Prof. Dr. Haibo Ge 《Angewandte Chemie (International ed. in English)》2018,57(13):3401-3405
Reported herein is the first example of a direct arylation of heteroarenes by a transient‐ligand‐directed strategy without the need to construct and deconstruct the directing group. A wide range of heteroarenes undergoes the coupling with diverse aryl iodides to assemble a large library of highly selective and functionalized 3‐arylthiophene‐2‐carbaldehydes. This route provides an opportunity to rapidly access new mechanofluorochromic materials. Moreover, a novel strategy for mechanochromic luminogens with chromism trends of red‐ and blue‐shifts has been disclosed for the first time by facile functional‐group modifications to a common structural core. 相似文献
999.
An Assembled Nanocomplex for Improving both Therapeutic Efficiency and Treatment Depth in Photodynamic Therapy 下载免费PDF全文
Hongqian Cao Dr. Lei Wang Dr. Yang Yang Dr. Juan Li Dr. Yanfei Qi Yue Li Ying Li Dr. Hao Wang Prof. Dr. Junbai Li 《Angewandte Chemie (International ed. in English)》2018,57(26):7759-7763
Photodynamic therapy (PDT) shows unique selectivity and irreversible destruction toward treated tissues or cells, but still has several problems in clinical practice. One is limited therapeutic efficiency, which is attributed to hypoxia in tumor sites. Another is the limited treatment depth because traditional photosensitizes are excited by short wavelength light (<700 nm). An assembled nano‐complex system composed of oxygen donor, two‐photon absorption (TPA) species, and photosensitizer (PS) was synthesized to address both problems. The photosensitizer is excited indirectly by two‐photon laser through intraparticle FRET mechanism for improving treatment depth. The oxygen donor, hemoglobin, can supply extra oxygen into tumor location through targeting effect for enhanced PDT efficiency. The mechanism and PDT effect were verified through both in vitro and in vivo experiments. The simple system is promising to promote two‐photon PDT for clinical applications. 相似文献
1000.
Smart DNA Hydrogel Integrated Nanochannels with High Ion Flux and Adjustable Selective Ionic Transport 下载免费PDF全文
Yafeng Wu Dianyu Wang Itamar Willner Ye Tian Prof. Lei Jiang 《Angewandte Chemie (International ed. in English)》2018,57(26):7790-7794
Nanochannels based on smart DNA hydrogels as stimulus‐responsive architecture are presented for the first time. In contrast to other responsive molecules existing in the nanochannel in monolayer configurations, the DNA hydrogels are three‐dimensional networks with space negative charges, the ion flux and rectification ratio are significantly enhanced. Upon cyclic treatment with K+ ions and crown ether, the DNA hydrogel states could be reversibly switched between less stiff and stiff networks, providing the gating mechanism of the nanochannel. Based on the architecture of DNA hydrogels and pH stimulus, cation or anion transport direction could be precisely controlled and multiple gating features are achieved. Meanwhile, G‐quadruplex DNA in the hydrogels might be replaced by other stimulus‐responsive DNA molecules, peptides, or proteins, and thus this work opens a new route for improving the functionalities of nanochannel by intelligent hydrogels. 相似文献