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1.
Xiao‐Feng Wu 《Chemical record (New York, N.Y.)》2015,15(5):949-963
In this account, the advances in base‐metal‐catalyzed oxidative transformations and metal‐free oxidation reactions developed in our group are summarized and discussed. Related achievements from other research groups are also discussed. 相似文献
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Dr. Chun Kiang Chua Prof. Martin Pumera 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(36):12550-12562
The rise in global demand for crucial chemical compounds has driven immense research in the fundamental science of catalysis. Graphene and its derivatives (chemically modified graphene, CMGs) have recently emerged as a new class of heterogeneous catalyst that promises economically viable and greener routes to these compounds. Although CMGs possess unique catalytic properties, the actual active sites are often points of discussion. Current minimal understanding on the possible effects of metallic impurities on the electrocatalytic performances of these CMGs calls forth the need to raise awareness on possible metallic impurities misrepresenting the actual chemical catalytic performances of the CMGs. This Minireview highlights the latest advances in the application of CMGs as catalysts, with an emphasis on the possible effects of metallic impurities on CMG catalysis. 相似文献
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Marcela Castano Kwang Su Seo Eun Hye Kim Matthew L. Becker Judit E. Puskas 《Macromolecular rapid communications》2013,34(17):1375-1380
Halo‐ester‐functionalized poly(ethylene glycol)s (PEGs) are successfully prepared by the transesterification of alkyl halo‐esters with PEGs using Candida antarctica lipase B (CALB) as a biocatalyst under the solventless conditions. Transesterifications of chlorine, bromine, and iodine esters with tetraethylene glycol monobenzyl ether (BzTEG) are quantitative in less than 2.5 h. The transesterification of halo‐esters with PEGs are complete in 4 h. 1H and 13C NMR spectroscopy with MALDI‐ToF and ESI mass spectrometry confirm the structure and purity of the products. This method provides a convenient and “green” process to effectively produce halo‐ester PEGs.
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Errika Voutyritsa Christoforos G. Kokotos 《Angewandte Chemie (International ed. in English)》2020,59(4):1735-1741
Direct alkylation of C(sp2)?H bonds to convert an aldehyde into a ketone is a notorious transformation, due to the laborious challenge of the formation of ketyl or acyl radicals. Herein, we report a green, cheap, metal‐free and efficient method for the hydroacylation of olefins in water. This photochemical protocol utilizes phenylglyoxylic acid, a commercially available small organic molecule, as the photoinitiator, water as the solvent and household fluorescent lamps as the irradiation source, leading to a broad substrate scope of products in moderate to good yields. A wide range of aromatic and aliphatic aldehydes, terminal and non‐terminal alkenes and pharmaceutically relevant molecules can be employed, without the need of directing groups and additives or metal catalysts. 相似文献
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Mustafa Y. Sen Judit E. Puskas Subramanyam Ummadisetty Joseph P. Kennedy 《Macromolecular rapid communications》2008,29(19):1598-1602
Methacrylate‐terminated polyisobutylenes (PIB‐MAs) were synthesized by transesterification of vinyl methacrylate by hydroxyl‐terminated polyisobutylenes (PIB‐OH) using Candida antarctica lipase B (Novozyme 435) catalyst in hexane at 50 °C. PIB CH2 CH2 CH2 OH and Glissopal OH, synthesized by anti‐Markovnikov hydrobromination of allyl‐terminated PIB and Glissopal®2300 followed by hydrolysis, were quantitatively converted into the corresponding PIB‐MAs. 1H and 13C NMR spectroscopy verified the formation of the expected structures. This “green” chemistry is a very promising methodology for polymer functionalization in general, and biomaterial synthesis in particular.
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Highly Stable,Water‐Dispersible Metal‐Nanoparticle‐Decorated Polymer Nanocapsules and Their Catalytic Applications 下载免费PDF全文
Gyeongwon Yun Dr. Zahid Hassan Jiyeong Lee Jeehong Kim Dr. Nam‐Suk Lee Dr. Nam Hoon Kim Dr. Kangkyun Baek Dr. Ilha Hwang Prof. Dr. Chan Gyung Park Prof. Dr. Kimoon Kim 《Angewandte Chemie (International ed. in English)》2014,53(25):6414-6418
A facile synthesis of highly stable, water‐dispersible metal‐nanoparticle‐decorated polymer nanocapsules (M@CB‐PNs: M=Pd, Au, and Pt) was achieved by a simple two‐step process employing a polymer nanocapsule (CB‐PN) made of cucurbit[6]uril (CB[6]) and metal salts. The CB‐PN serves as a versatile platform where various metal nanoparticles with a controlled size can be introduced on the surface and stabilized to prepare new water‐dispersible nanostructures useful for many applications. The Pd nanoparticles on CB‐PN exhibit high stability and dispersibility in water as well as excellent catalytic activity and recyclability in carbon–carbon and carbon–nitrogen bond‐forming reactions in aqueous medium suggesting potential applications as a green catalyst. 相似文献
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Dry Chemistry of Ferrate(VI): A Solvent‐Free Mechanochemical Way for Versatile Green Oxidation 下载免费PDF全文
Zhao‐Yang Zhang Deyang Ji Wenting Mao Yu Cui Qing Wang Prof. Lu Han Prof. Hongliang Zhong Prof. Zhongming Wei Prof. Yixin Zhao Prof. Kasper Nørgaard Prof. Tao Li 《Angewandte Chemie (International ed. in English)》2018,57(34):10949-10953
The +6 oxidation state of iron generally exists in the form of ferrate(VI) with high redox potential and environmentally friendly nature. Although ferrate(VI) has been known for over a century, its chemistry is still limited to the solvent‐based reactions that suffers from the insolubility/instability of this oxidant and the environmental issues caused by hazardous solvents. Herein, we explore the solvent‐free reactivity of ferrate(VI) under mechanical milling, revealing that its strong oxidizing power is accessible in the “dry” solid state towards a broad variety of substrates, for example, aromatic alcohols/aldehydes and carbon nanotubes. More significantly, solvent‐free mechanochemistry also reshapes the oxidizing ability of ferrate(VI) due to the underlying solvent‐free effect and the promotive mechanical actions. This study opens up a new chemistry of ferrate(VI) with promising application in green oxidative transformation of both organic and inorganic substrates. 相似文献
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Sonia DeAngelis Mario Franco Alessandra Triminì Ana Gonzlez Raquel Sainz Leonardo Degennaro Giuseppe Romanazzi Claudia Carlucci Valentina Petrelli Alejandro delaEsperanza Asier Goi Rafael Ferritto Jos Luis Acea Renzo Luisi M. Beln Cid 《化学:亚洲杂志》2019,14(17):3011-3018
The use of graphene derivatives as supports improves the properties of heterogeneous catalysts, with graphene oxide (GO) being the most frequently employed. To explore greener possibilities as well as to get some insights into the role of the different graphenic supports (GO, rGO, carbon black, and graphite nanoplatelets), we prepared, under the same standard conditions, a variety of heterogeneous Cu catalysts and systematically evaluated their composition and catalytic activity in azide–alkyne cycloadditions as a model reaction. The use of sustainable graphite nanoplatelets (GNPs) afforded a stable CuI catalyst with good recyclability properties, which are compatible with flow conditions, and able to catalyze other reactions such as the regio‐ and stereoselective sulfonylation of alkynes (addition reaction) and the Meerwein arylation (single electron transfer process). 相似文献
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Kyle M. Lambert Prof. Dr. James M. Bobbitt Sherif A. Eldirany Liam E. Kissane Rose K. Sheridan Zachary D. Stempel Francis H. Sternberg Prof. Dr. William F. Bailey 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(15):5156-5159
Synergism among several intertwined catalytic cycles allows for selective, room temperature oxidation of primary amines to the corresponding nitriles in 85–98 % isolated yield. This metal‐free, scalable, operationally simple method employs a catalytic quantity of 4‐acetamido‐TEMPO (ACT; TEMPO=2,2,6,6‐tetramethylpiperidine N‐oxide) radical and the inexpensive, environmentally benign triple salt oxone as the terminal oxidant under mild conditions. Simple filtration of the reaction mixture through silica gel affords pure nitrile products. 相似文献
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Dr. Esteban Mejía Dr. Shu‐Ping Luo Dr. Michael Karnahl Aleksej Friedrich Dr. Stefanie Tschierlei Dr. Annette‐Enrica Surkus Dr. Henrik Junge Prof. Dr. Serafino Gladiali Prof. Dr. Stefan Lochbrunner Prof. Dr. Matthias Beller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(47):15972-15978
A series of heteroleptic copper(I) complexes with bidentate $\widehat{PP}$ and $\widehat{NN}$ chelate ligands was prepared and successfully applied as photosensitizers in the light‐driven production of hydrogen, by using [Fe3(CO)12] as a water‐reduction catalyst (WRC). These systems efficiently reduces protons from water/THF/triethylamine mixtures, in which the amine serves as a sacrificial electron donor (SR). Turnover numbers (for H) up to 1330 were obtained with these fully noble‐metal‐free systems. The new complexes were electrochemically and photophysically characterized. They exhibited a correlation between the lifetimes of the MLCT excited state and their efficiency as photosensitizers in proton‐reduction systems. Within these experiments, considerably long excited‐state lifetimes of up to 54 μs were observed. Quenching studies with the SR, in the presence and absence of the WRC, showed that intramolecular deactivation was more efficient in the former case, thus suggesting the predominance of an oxidative quenching pathway. 相似文献
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Loading of a Coordination Polymer Nanobelt on a Functional Carbon Fiber: A Feasible Strategy for Visible‐Light‐Active and Highly Efficient Coordination‐Polymer‐Based Photocatalysts 下载免费PDF全文
Prof. Dr. Xin‐Xin Xu Dr. Hong‐Yu Yang Dr. Zhen‐Yu Li Prof. Dr. Xiao‐Xia Liu Prof. Dr. Xiu‐Li Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(9):3821-3830
To improve the photocatalytic properties of coordination polymers under irradiation in the visible‐light region, coordination polymer nanobelts (CPNB) were loaded on functional carbon fiber (FCF) through the use of a simple colloidal blending process. The resulting coordination polymer nanobelt loaded functional carbon fiber composite material (CPNB/FCF) exhibited dramatically improved photocatalytic activity for the degradation of rhodamine B (RhB) under visible‐light irradiation. Optical and electrochemical methods illustrated the enhanced photocatalytic activity of CPNB/FCF originated from high separation efficiency of photogenerated electrons and holes on the interface of CPNB and FCF, which was produced by the synergy effect between them. In the composite material, the role of FCF could be described as photosensitizer and good electron transporter. For FCF, the number of functional groups on its surface has a significant influence on the photocatalytic performance of the resulting CPNB/FCF composite material, and an ideal FCF carrier was obtained as a highly efficient CPNB/FCF photocatalyst. CPNB/FCF showed outstanding stability during the degradation of rhodamine B (RhB); thus, the material is suitable for use as a photocatalyst in the treatment of organic dyes in water. 相似文献
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Juliano B. Azeredo Filipe Penteado Vanessa Nascimento Luca Sancineto Antonio L. Braga Eder Joo Lenardao Claudio Santi 《Molecules (Basel, Switzerland)》2022,27(5)
Organoselenium compounds have been successfully applied in biological, medicinal and material sciences, as well as a powerful tool for modern organic synthesis, attracting the attention of the scientific community. This great success is mainly due to the breaking of paradigm demonstrated by innumerous works, that the selenium compounds were toxic and would have a potential impact on the environment. In this update review, we highlight the relevance of these compounds in several fields of research as well as the possibility to synthesize them through more environmentally sustainable methodologies, involving catalytic processes, flow chemistry, electrosynthesis, as well as by the use of alternative energy sources, including mechanochemical, photochemistry, sonochemical and microwave irradiation. 相似文献
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Dr. Adela I. Carrillo Dr. Ayda Elhage Prof. Dr. M. Luisa Marin Dr. Anabel E. Lanterna 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(65):14928-14934
A mechanistic study is herein presented for the use of heterogeneous photocatalysts based on perylene moieties. First, the successful immobilization of perylene diimides (PDI) on silica matrices is demonstrated, including their full characterization by means of electronic microscopy, surface area measurements, powder XRD, thermogravimetric analysis, and FTIR, 29Si and 13C solid-state NMR, fluorescence, and diffuse reflectance spectroscopies. Then, the photoredox activity of the material was tested by using two model reactions, alkene oxidation and 4-nitrobenzylbromide reduction, and mechanistic studies were performed. The mechanistic insights into their photoredox activity show they have promising dual photocatalytic activity for both organic oxidations and reductions. 相似文献
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Régis M. Gauvin Dr. Frank Buch Laurent Delevoye Dr. Sjoerd Harder Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(17):4382-4393
Bound to stay heteroleptic : Grafting of homoleptic benzyl and amide calcium reagents onto silica affords well‐defined supported heteroleptic species, catalytically active in hydrosilylation, hydroamination, and styrene polymerization. The fact that attempts to generate a molecular model were thwarted by the Schlenk equilibrium affording the homoleptic compound (see scheme) emphasizes the importance of immobilization as an approach for the syntheses of heteroleptic calcium complexes.
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A Cinchona Alkaloid‐Functionalized Mesostructured Silica for Construction of Enriched Chiral β‐Trifluoromethyl‐β‐Hydroxy Ketones over An Epoxidation‐Relay Reduction Process 下载免费PDF全文
Cuibao Li Xiaomin Shu Liang Li Genwei Zhang Ronghua Jin Tanyu Cheng Prof. Guohua Liu 《化学:亚洲杂志》2016,11(14):2072-2077
A cinchona alkaloid‐functionalized heterogeneous catalyst is prepared through a thiol‐ene click reaction of chiral N‐(3,5‐ditrifluoromethylbenzyl)quininium bromide and a mesostructured silica, which is obtained by co‐condensation of 1,2‐bis(triethoxysilyl)ethane and 3‐(triethoxysilyl)propane‐1‐thiol. Structural analyses and characterizations disclose its well‐defined chiral single‐site active center, and electron microscopy images reveal its monodisperse property. As a heterogenous catalyst, it enables an efficient asymmetric epoxidation of achiral β‐trifluoromethyl‐β,β‐disubstituted enones, the obtained chiral products can then be converted easily into enriched chiral β‐trifluoromethyl‐β‐hydroxy ketones through a sequential epoxidation‐relay reduction process. Furthermore, such a heterogeneous catalyst can be recovered conveniently and reused in asymmetric epoxidation of 4,4,4‐trifluoro‐1,3‐diphenylbut‐2‐enone, showing an attractive feature in a practical construction of enriched chiral β‐CF3‐substituted molecules. 相似文献
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Selective Catalytic Synthesis Using the Combination of Carbon Dioxide and Hydrogen: Catalytic Chess at the Interface of Energy and Chemistry 下载免费PDF全文
Prof. Dr. Jürgen Klankermayer Sebastian Wesselbaum Dr. Kassem Beydoun Prof. Dr. Walter Leitner 《Angewandte Chemie (International ed. in English)》2016,55(26):7296-7343
The present Review highlights the challenges and opportunities when using the combination CO2/H2 as a C1 synthon in catalytic reactions and processes. The transformations are classified according to the reduction level and the bond‐forming processes, covering the value chain from high volume basic chemicals to complex molecules, including biologically active substances. Whereas some of these concepts can facilitate the transition of the energy system by harvesting renewable energy into chemical products, others provide options to reduce the environmental impact of chemical production already in today's petrochemical‐based industry. Interdisciplinary fundamental research from chemists and chemical engineers can make important contributions to sustainable development at the interface of the energetic and chemical value chain. The present Review invites the reader to enjoy this exciting area of “catalytic chess” and maybe even to start playing some games in her or his laboratory. 相似文献
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Heterogeneous Rhodium‐Catalyzed Aerobic Oxidative Dehydrogenative Cross‐Coupling: Nonsymmetrical Biaryl Amines 下载免费PDF全文
Dr. Kenji Matsumoto Prof. Masahiro Yoshida Prof. Mitsuru Shindo 《Angewandte Chemie (International ed. in English)》2016,55(17):5272-5276
The first heterogeneously catalyzed oxidative dehydrogenative cross‐coupling of aryl amines is reported herein. 2‐Naphthylamine analogues were reacted with various electron‐rich arenes using a heterogeneous Rh/C catalyst under mild aerobic conditions, thus affording nonsymmetrical biaryl amines in excellent yields with high selectivities. This reaction provides a mild, operationally simple, and efficient approach for the synthesis of biaryls which are important to pharmaceutical and materials chemistry. 相似文献