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Chemistry, An Asian Journal

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https://www.readbyqxmd.com/read/29791085/sulfonylation-of-benzylic-c-h-bond-through-a-reaction-of-aryl-o-tolyl-methanones-with-sulfonyl-hydrazides-or-sulfonyl-chlorides
#1
Xinxing Gong, Jiahao Chen, Xiaofang Li, Wenlin Xie, Jie Wu
A benzylic C-H bond sulfonylation of aryl(o-tolyl)methanones with arylsulfonyl hydrazides or arylsulfonyl chlorides is reported. Both arylsulfonyl hydrazides and arylsulfonyl chlorides are employed as sulfonylation reagents to complete this transformation under different conditions. During the reaction process, enols are generated in situ from aryl(o-tolyl)methanones under ultraviolet irradiation, which react with sulfonyl radicals providing a range of aryl(2-(arylsulfonylmethyl)aryl)methanones.
May 23, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29791067/synergistic-catalysis-enabled-reaction-of-2-indolymethanols-with-oxonium-ylides-construction-of-3-indolyl-3-alkoxy-oxindole-framework
#2
Chun Ma, Jia-Yu Zhou, Yi-Zhu Zhang, Yin-Chun Jiao, Guang-Jian Mei, Feng Shi
A synergistic catalysis-enabled reaction of 2-indolymethanols with oxonium ylides has been established, which makes use of the three-component reaction of 3-diazooxindoles, alcohols and 2-indolymethanols under the cooperative catalysis of metal complex and Brønsted acid. This reaction has not only provided a new approach for constructing 3-indolyl-3-alkoxy oxindole scaffolds by utilizing the indole C3-electrophilicity, but also realized a nucleophilic addition of metal associated ylide to 2-indolylmethanols for the first time...
May 23, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29790649/hyperpolarized-nmr-d-dnp-phip-and-sabre
#3
Kirill Viktorovich Kovtunov, Ekaterina Pokochueva, Oleg Salnikov, Samuel Cousin, Dennis Kurzbach, Basile Vuichoud, Sami Jannin, Eduard Chekmenev, Boyd Goodson, Danila Barskiy, Igor Koptyug
NMR signals intensities can be enhanced by several orders of magnitude via utilization of techniques for hyperpolarization of different molecules, and it allows one to overcome the main sensitivity challenge of modern NMR/MRI techniques. Hyperpolarized fluids can be successfully used in different applications of material science and biomedicine. This focus review covers the fundamentals of the preparation of hyperpolarized liquids and gases via dissolution dynamic nuclear polarization (d-DNP) and parahydrogen-based techniques such as signal amplification by reversible exchange (SABRE) and parahydrogen-induced polarization (PHIP) in both heterogeneous and homogeneous processes...
May 23, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29786970/density-functional-theory-calculations-revealing-metal-like-band-structures-for-ultrathin-ge-111-and-211-surface-layers
#4
Chih-Shan Tan, Michael Hsuan-Yi Huang
To find out if germanium should also possess facet-dependent electrical conductivity properties, surface state density functional theory (DFT) calculations were performed on 1-6 layers of Ge (100), (110), (111), and (211) planes. Tunable Ge (100) and (110) planes always present the same semiconducting band structure with a band gap of 0.67 eV expected of bulk germanium. In contrast, 1, 2, 4, and 5 layers of Ge (111) and (211) plane models show metal-like band structures with continuous density of states (DOS) throughout the entire band...
May 21, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29781172/manganese-catalyzed-hydrosilylation-reactions
#5
Congyang Wang, Xiaoxu Yang
In the past few decades, manganese-catalyzed hydrosilylation of C=O or C=C/C≡C unsaturated bonds achieved enormous developments. In this focus review, the hydrosilylation reactions of alkene, alkyne and carbonyl-containing substrates catalyzed by manganese complexes, are summarized. Moreover, the mechanisms of manganese-catalyzed hydrosilylation are discussed briefly.
May 20, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29781151/facile-separation-spectroscopic-identification-and-electrochemical-properties-of-higher-trifluoromethylated-derivatives-of-the-70-fullerene
#6
Maria P Kosaya, Alexey V Rybalchenko, Natalia S Lukonina, Olga N Mazaleva, Ilya N Ioffe, Vitaliy Yu Markov, Sergey I Troyanov, Lev N Sidorov, Nadezhda B Tamm, Alexey A Goryunkov
We survey structure and electronic properties of the family of higher trifluoromethylated C70(CF3)n molecules with n=14, 16, 18, and 20. Twenty two available compounds, of which thirteen are newly obtained and characterized, demonstrate broad diversity of π-system topologies, having enabled us to study the interplay between the CF3 addition pattern and the electronic properties. UV-vis spectroscopic and cyclic voltammetric studies demonstrate importance of the exact addition pattern rather than the plain number of addends...
May 20, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29779241/visible-light-driven-chemoselective-hydrogenation-of-nitroarenes-to-anilines-in-water-via-graphitic-carbon-nitride-metal-free-photocatalysis
#7
Gang Xiao, Peifeng Li, Yilin Zhao, Shengnan Xu, Haijia Su
Green and efficient procedures are highly required for the chemoselective hydrogenation of functionalized nitroarenes to industrially important anilines. Here, we show that visible-light-driven, chemoselective hydrogenation of functionalized nitroarenes bearing the sensitive groups to anilines can be achieved in good to excellent yields (82-100%) in water under relatively mild conditions, catalyzed by low-cost and recyclable graphitic carbon nitride. It is also applicable in gram-scale reaction with 86% yield of aniline...
May 20, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29774983/mechanistic-insights-into-the-ni-catalyzed-reductive-carboxylation-of-c-o-bonds-in-aromatic-esters-with-co-2-understanding-remarkable-ligand-and-traceless-directing-group-effects
#8
Yan-Li Han, Bing-Yuan Zhao, Kun-Yao Jiang, Hui-Min Yan, Zhu-Xia Zhang, Wen-Jing Yang, Zhen Guo, Yan-Rong Li
The mechanism of the Ni0 -catalyzed reductive carboxylation reaction of C(sp2 )-O and C(sp3 )-O bonds in aromatic esters with CO2 to access valuable carboxylic acids was comprehensively studied by using DFT calculations. Computational results revealed that this transformation was composed of several key steps: C-O bond cleavage, reductive elimination, and/or CO2 insertion. Of these steps, C-O bond cleavage was found to be rate-determining, and it occurred through either oxidative addition to form a NiII intermediate, or a radical pathway that involved a bimetallic species to generate two NiI species through homolytic dissociation of the C-O bond...
May 18, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29774978/n-heterocyclic-carbene-protected-ag-nanoparticles-immobilized-on-polyacrylonitrile-fiber-as-efficient-catalysts-for-a-three-component-coupling-reaction
#9
Jian Cao, Hongqi Tian
Metal nanoparticles (NPs) are routinely stabilized by the introduction of capping agents or their distribution on supports. In this context, we report the preparation and characterization of N-heterocyclic carbene (NHC)-stabilized silver NPs supported on polyacrylonitrile fiber (PANF). As a result, Ag loadings of up to 8 % and particle sizes of 11.0±3.2 nm were achieved. This novel nanocomposite catalyst demonstrated high activity in addition to excellent stability and reusability in the three-component reaction between alkynes, haloalkanes, and amines...
May 18, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29774662/highly-nitrogen-doped-porous-carbon-derived-from-zeolitic-imidazolate-framework-8-for-co2-capture
#10
Xiancheng Ma, Liqing Li, Ruofei Chen, Chunhao Wang, Haoyang Li, Hailong Li
CO2 adsorption capacity of nitrogen-doped porous carbon depends to a large nitrogen doping levels and high surface area in previous studies. However, it seems difficult to incorporate large amounts of nitrogen while maintaining a high surface area and pore structure. Here we have reported porous carbon having a nitrogen content of up to 25.52% and specific surface area of 948 m2 g-1, which is prepared by pyrolyzing the nitrogen-containing zeolite imidazole framework-8 and urea composite at 650 °C under a nitrogen atmosphere...
May 18, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29771008/dianionic-titanyl-and-vanadyl-cation-2-m-iv-o-pc-4-2-phthalocyanine-salts-containing-pc-4-macrocycles
#11
Dmitri V Konarev, Alexey V Kuzmin, Salavat S Khasanov, Alexey L Litvinov, Akihiro Otsuka, Hideki Yamochi, Hiroshi Kitagawa, Rimma N Lyubovskaya
In this study, the titanyl and vanadyl phthalocyanine (Pc) salts (Bu4 N+ )2 [MIV O(Pc4- )]2- (M=Ti, V) and (Bu3 MeP+ )2 [MIV O(Pc4- )]2- (M=Ti, V) with [MIV O(Pc4- )]2- dianions were synthesized and characterized. Reduction of MIV O(Pc2- ) carried out with an excess of sodium fluorenone ketyl in the presence of Bu4 N+ or Bu3 MeP+ is exclusive to the phthalocyanine centers, forming Pc4- species. During reduction, the metal +4 charge did not change, implying that Pc is an non-innocent ligand. The Pc negative charge increase caused the C-N(pyr) bonds to elongate and the C-N(imine) bonds to alternate, thus increasing the distortion of Pc...
May 17, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29771003/synthesis-and-characterisation-of-stable-phosphorus-carbabetaines
#12
Hikaru Yanai, Pedro Almendros, Saori Takahashi, Carlos Lázaro-Milla, Benito Alcaide, Takashi Matsumoto
Phosphorus 1,3- and 1,4-carbabetaines with 'P(+)-C-C(-)' and 'P(+)-C-C-C(-)' structures, in which the carbanion moiety was significantly stabilised by two triflyl groups, were synthesised. Through their crystal structures, it was suggested that attractive interactions between the anionic and cationic moieties were negligibly weak. This point was corroborated by Natural Bond Orbital (NBO) and Bader's Quantum Theory of Atoms in Molecules (QTAIM) analyses. In contrast, the same analysis of known 1,3-carbabetaine equivalent depicted as 'P(+)-C-C=C-O(-)' resonance structure revealed pronounced charge-transfer bonding between the anionic and cationic atoms...
May 17, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29770604/synthesis-of-black-phosphorus-quantum-dots-with-high-quantum-yield-by-pulsed-laser-ablation-for-cell-bioimaging
#13
Xiaoling Zhang, Xin Ren, Fang Zhang
Black phosphorus quantum dots (BPQDs) with an average diameter of ≈ 6 nm and a height of ≈1.1 nm are successfully synthesized by using a pulsed laser ablation (PLA) method in isopropyl ether (IPE) solvent. PL quantum yield of the as-prepared sample is as high as 20.7% which is 3 times that of the BPQDs prepared by probe ultrasonic exfoliation (approximately 7.2%) for the first time. The stable and blue-violet photoluminescence (PL) emission of the BPQDs is observed, which is elucidated that electrons transit from the LUMO energy level to the HOMO energy level as well as energy levels below the HOMO ( H1 and H2 )...
May 16, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29767480/n-heterocyclic-carbene-catalyzed-annulation-of-ylides-with-ynals-direct-access-to-%C3%AE-pyrones
#14
Jian Wang, Ming Lang, Qianfa Jia
-Pyones are frequently observed as the core in numerous natural products and biologically important molecules. They have exhibited promising biological activities, such as anti-HIV, antimicrobial, antifungal, telomerase inhibition, pheromonal, androgen, cardiotonic, neurotoxic and phytotoxic effects. In medicinal chemistry, α-pyones often serve as convenient precursors for the assembly of other medicinal important structures. Therefore, the development of an efficient synthetic protocol for the construction of diversified -pyrone derivatives tends to be interesting and highly demanded...
May 16, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29767475/iron-catalyzed-vinylic-c-h-alkylation-with-alkyl-peroxides
#15
Hongli Bao, Liang Ge, Wujun Jian, Huan Zhou, Shaowei Chen, Changqing Ye, Fei Yu, Bo Qian, Yajun Li
A variety of alkyl peresters and alkyl diacyl peroxides which are readily accessible from carboxylic acids are utilized as general primary, secondary, and tertiary alkylating reagents for iron catalyzed vinylic C-H alkylation of vinyl arenes, dienes, and 1,3-enynes. This transformation affords the olefinic products in up to 98% yields with high E/Z values. A broad range of functionalities including carboxyl, boronic acid, methoxy, ester, amino, and halides are tolerated. This protocol provides a facile approach to some olefins that are difficult to access, and hence offers an alternative to the existing systems...
May 16, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29763525/-bis-imidazolyl-bh%C3%A2-bis-triazolyl-bh%C3%A2-ionic-liquids-with-high-density-and-energy-capacity
#16
Nianming Jiao, Hao Li, Yanqiang Zhang, Long Liu, Suojiang Zhang
[Bis(imidazolyl)-BH₂]+[bis(triazolyl)-BH₂]- and [bis- (imidazolyl)-BH₂]+[tris(triazolyl)-BH]- were first synthesized, whose cations and anions were all functionalized with B-H groups and azoles. As B-H groups contributing to hypergolic activity and azole groups improving the energy outputs, the resulting ionic liquids exhibited ignition delay time as low as 20 ms and energy output as high as 461.1 kJ mol-1. Besides, densities (1.07-1.22 g∙cm-3) and density-specific impulse (ρIsp, ~ 360 s g cm-3) reach to relatively high level...
May 15, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29761658/carbeniophosphines-vs-phosphoniocarbenes-the-role-of-the-positive-charge
#17
Yves Canac
The chemistry of carbeniophosphines and phosphoniocarbenes, whose general structures derive formally from the three-component "carbene/phosphine/positive charge" association, is presented. These two complementary classes of carbon-phosphorus based ligands defined by the presence of an inverted cationic coordinating structure [C+~P: vs. P+~C:] have the common purpose of positioning a positive charge in the vicinity of the metal center. Through selected examples, synthetic methods, coordination properties and general reactivity of both cationic species are described...
May 15, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29757499/silica-gel-as-a-promoter-of-sequential-aza-michael-michael-reactions-of-amines-and-propiolic-esters-solvent-free-and-metal-free-synthesis-of-polyfunctionalized-conjugated-dienes
#18
Jovana Aleksić, Milovan Stojanović, Marija Baranac-Stojanović
We present an efficient and simple, metal-free and solvent-free silica gel-promoted synthesis of functionalized conjugated dienes by sequential aza-Michael/Michael reactions starting from commercially available primary amines and propiolic esters. The scope and usefulness of the method is demonstrated on 31 examples, including a range of propiolic esters, aliphatic amines and differently substituted aromatic amines. In the case of aliphatic amines, the products are obtanied within 0.5-4 h in 52-85% yield compared with 3...
May 14, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29756680/design-of-single-site-photocatalyst-using-metal-organic-framework-as-matrix
#19
Meicheng Wen, Kohsuke Mori, Yasutaka Kuwahara, Taicheng An, Hiromi Yamashita
Single-site photocatalyst generally displays excellent photocatalytic activtiy and considerable high stability as compared to homogeneous catalytic system. A rational structural design of single-site photocatalyst with isolated, uniform and spatially separated active sites in a given solid is of prime importance to achieve high photocatalytic activity. Intense attentions have been focused on the engineering and fabrication of single-site photocatalys by using porous materials as platform. Metal-organic frameworks (MOFs) hold great potential for the design and fabrication of single-site photocatalysts due to their remarkable porosity, ultrahigh surface area, extraordinary tailorability and significant diversity...
May 14, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29756306/mussel-inspired-polydopamine-coating-for-flexible-ternary-resistive-memory
#20
Yong-Yan Zhao, Xue-Feng Cheng, Wen-Hu Qian, Jin Zhou, Jing-Hui He, Hua Li, Qing-Feng Xu, Na-Jun Li, Dong-Yun Chen, Jian-Mei Lu
In recent years, numerous organic molecules and polymers carrying various functional groups were synthesized and used in fabrication of wearable electronic devices. Compared to previous materials suffer from poisonousness, stiffness and complex film fabrication, we circumvent above matters by taking advantage of mussel-inspired polydopamine as our active material to realize random resistive access memories (RRAMs). Polydopamine thin film were grown on indium tin oxide glass catalyzed by Cu2SO4/H2O2 and characterized by Fourier infrared spectroscope (FT-IR), Ultra-violet (UV-Vis) and scanning electron microscope...
May 14, 2018: Chemistry, An Asian Journal
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