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https://www.readbyqxmd.com/read/28941414/synthesis-spectral-and-luminescence-study-crystal-structure-determination-and-dft-calculation-of-binuclear-palladium-ii-complexes
#1
S Seyfi, R Alizadeh, M Darvish Ganji, V Amani
Binuclear palladium(II) complexes with metal-metal (d(8)-d(8)) bonding interaction were synthesized by reactions of the 1-methyl-1H-1,2,3,4-tetrazole-5-thiol (Hmtzt) or a mixture of Hmtzt and 1,3-propanediamine (1,3-pda) ligands. Complex [Pd2(μ-mtzt)4]·2CH3CN (1) was synthesized by the reaction of Pd(OAc)2 with Hmtzt dissolved in acetonitrile and complex [Pd2(μ-mtzt)2(mtzt)2(1,3-pda)] (2) was synthesized by reaction of a mixture of Hmtzt and 1,3-propanediamine (dissolved in methanol) with PdCl2 (dissolved in acetonitrile) and were identified through elemental analysis, IR, UV-Vis, (1)H NMR, luminescence spectroscopy as well as single-crystal X-ray diffraction method...
September 14, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28941352/interlaboratory-variability-of-urinary-iodine-measurements
#2
Till Ittermann, Simone Johner, Harald Below, Matthias Leiterer, Michael Thamm, Thomas Remer, Henry Völzke
BACKGROUND: The iodine status of populations is usually assessed by median urinary iodine concentrations (UIC) in population-based studies, but it is unclear to which extent UIC are comparable across different laboratories. The aim of our study was to investigate the variability of UIC measurements across three well-established German laboratories with long-term clinical-chemical expertise in iodine measurements and to compare these results to the gold standard inductively coupled plasma mass spectrometry (ICP-MS)...
September 23, 2017: Clinical Chemistry and Laboratory Medicine: CCLM
https://www.readbyqxmd.com/read/28938145/six-scalemic-mixtures-of-6-monosubstituted-dihydrobenzophenanthridine-alkaloids-from-chelidonium-majus-and-optically-active-structures-of-enantiomers
#3
An-Jun Deng, Hai-Jing Zhang, Qian Li, Zhi-Hong Li, Zhi-Hui Zhang, Lian-Qiu Wu, Li Li, Hai-Lin Qin
Six pairs of previously undescribed 6-monosubstituted dihydrobenzophenanthridine alkaloids were separated as corresponding six scalemic mixtures from the aerial part of Chelidonium majus. The elucidation for the 2D structures of these alkaloids was achieved using regular spectroscopic and chemical methods. The assignment of scalemic-mixture nature was achieved using combined examinations of their NMR data, CD spectra, calculation of specific rotations, and chiral HPLC profiles. The identification for the relative configurations of alkaloids possessing two asymmetric carbons directly connected up by a rotatable sp(3)-sp(3) carbon-carbon single bond was significantly facilitated by discussing the erythro and threo relative configurations defined by the mutuality of the orders of decreasing steric hindrances between the two sets of ligands linked to the two chiral centers...
September 19, 2017: Phytochemistry
https://www.readbyqxmd.com/read/28937961/regulation-of-chromatin-assembly-and-cell-transformation-by-formaldehyde-exposure-in-human-cells
#4
Danqi Chen, Lei Fang, Shenglin Mei, Hongjie Li, Xia Xu, Thomas L Des Marais, Kun Lu, X Shirley Liu, Chunyuan Jin
BACKGROUND: Formaldehyde (FA) is an environmental and occupational chemical carcinogen. Recent studies have shown that exogenous FA causes only a modest increase in DNA adduct formation compared with the amount of adducts formed by endogenous FA, raising the possibility that epigenetic mechanisms may contribute to FA-mediated carcinogenicity. OBJECTIVES: We investigated the effects of FA exposure on histone modifications and chromatin assembly. We also examined the role of defective chromatin assembly in FA-mediated transcription and cell transformation...
September 21, 2017: Environmental Health Perspectives
https://www.readbyqxmd.com/read/28937906/protein-activation-in-periapical-reaction-to-iodoform-containing-root-canal-sealer
#5
Nili Tickotsky, Moti Moskovitz
OBJECTIVES: An association between root canal sealers and periapical lesions in primary dentition has been suggested, yet the chemical-protein interactions that may be involved in it have not been studied. The present study explored root sealer components' effect on periapical tissue proteins using bioinformatics tools. STUDY DESIGN: For each chemical component of Endoflas F.S. root sealing material we identified the known and predicted target proteins, using STITCH (search tool for interactions of chemicals http://stitch...
September 22, 2017: Journal of Clinical Pediatric Dentistry
https://www.readbyqxmd.com/read/28937679/total-synthesis-of-tubingensin-b-enabled-by-the-strategic-use-of-an-aryne-cyclization
#6
Michael A Corsello, Junyong Kim, Neil K Garg
Tubingensin B is an indole diterpenoid that bears a daunting chemical structure featuring a disubstituted carbazole unit, five stereogenic centres-three of which are quaternary-and a decorated [3.2.2]-bridged bicycle. We describe our synthetic design toward a concise and enantiospecific total synthesis of tubingensin B, which hinges on the strategic use of a transient aryne intermediate. Although initial studies led to unexpected reaction outcomes, we ultimately implemented a sequence of carbazolyne cyclization followed by Rh-catalysed fragmentation to install the seven-membered ring and vicinal quaternary stereocentres of the natural product...
October 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28937677/synthesis-and-materialization-of-a-reaction-diffusion-french-flag-pattern
#7
Anton S Zadorin, Yannick Rondelez, Guillaume Gines, Vadim Dilhas, Georg Urtel, Adrian Zambrano, Jean-Christophe Galas, André Estevez-Torres
During embryo development, patterns of protein concentration appear in response to morphogen gradients. These patterns provide spatial and chemical information that directs the fate of the underlying cells. Here, we emulate this process within non-living matter and demonstrate the autonomous structuration of a synthetic material. First, we use DNA-based reaction networks to synthesize a French flag, an archetypal pattern composed of three chemically distinct zones with sharp borders whose synthetic analogue has remained elusive...
October 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28937670/feshbach-resonances-in-the-exit-channel-of-the-f%C3%A2-%C3%A2-ch3oh%C3%A2-%C3%A2-%C3%A2-hf%C3%A2-%C3%A2-ch3o-reaction-observed-using-transition-state-spectroscopy
#8
Marissa L Weichman, Jessalyn A DeVine, Mark C Babin, Jun Li, Lifen Guo, Jianyi Ma, Hua Guo, Daniel M Neumark
The transition state governs how chemical bonds form and cleave during a chemical reaction and its direct characterization is a long-standing challenge in physical chemistry. Transition state spectroscopy experiments based on negative-ion photodetachment provide a direct probe of the vibrational structure and metastable resonances that are characteristic of the reactive surface. Dynamical resonances are extremely sensitive to the topography of the reactive surface and provide an exceptional point of comparison with theory...
October 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28937667/direct-conversion-of-co2-into-liquid-fuels-with-high-selectivity-over-a-bifunctional-catalyst
#9
Peng Gao, Shenggang Li, Xianni Bu, Shanshan Dang, Ziyu Liu, Hui Wang, Liangshu Zhong, Minghuang Qiu, Chengguang Yang, Jun Cai, Wei Wei, Yuhan Sun
Although considerable progress has been made in carbon dioxide (CO2) hydrogenation to various C1 chemicals, it is still a great challenge to synthesize value-added products with two or more carbons, such as gasoline, directly from CO2 because of the extreme inertness of CO2 and a high C-C coupling barrier. Here we present a bifunctional catalyst composed of reducible indium oxides (In2O3) and zeolites that yields a high selectivity to gasoline-range hydrocarbons (78.6%) with a very low methane selectivity (1%)...
October 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28937606/a-novel-nanocomposite-as-an-efficient-adsorbent-for-the-rapid-adsorption-of-ni-ii-from-aqueous-solution
#10
Xiaotao Zhang, Ximing Wang, Zhangjing Chen
A sulfhydryl-lignocellulose/montmorillonite (SLT) nanocomposite was prepared using a chemical intercalation reaction. The SLT nanocomposite was characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Transmission Electron Microscopy (TEM), the results demonstrated that an intercalated-exfoliated nanostructure was formed in the SLT nanocomposite. Batch experiments were conducted to optimize parameters such as SLT nanocomposite dosage, the initial concentration of Ni(II), solution pH, temperature, and time...
September 22, 2017: Materials
https://www.readbyqxmd.com/read/28937596/synthesis-of-multi-walled-carbon-nanotubes-from-plastic-waste-using-a-stainless-steel-cvd-reactor-as-catalyst
#11
Pranav K Tripathi, Shane Durbach, Neil J Coville
The disposal of non-biodegradable plastic waste without further upgrading/downgrading is not environmentally acceptable and many methods to overcome the problem have been proposed. Herein we indicate a simple method to make high-value nanomaterials from plastic waste as a partial solution to the environmental problem. Laboratory-based waste centrifuge tubes made of polypropylene were chosen as a carbon source to show the process principle. In the process, multi-walled carbon nanotubes (MWCNTs) were synthesized from plastic waste in a two-stage stainless steel 316 (SS 316) metal tube that acted as both reactor vessel and catalyst...
September 22, 2017: Nanomaterials
https://www.readbyqxmd.com/read/28937167/an-unsaturated-metal-site-promoted-approach-to-construct-strongly-coupled-noble-metal-hnb3o8-nanosheets-for-efficient-thermo-photo-catalytic-reduction
#12
Lijuan Shen, Yuzhou Xia, Sen Lin, Shijing Liang, Ling Wu
Creating two-dimensional (2D) crystal-metal heterostructures with an ultrathin thickness has spurred increasing research endeavors in catalysis because of its fascinating opportunities in tuning the electronic state at the surface and enhancing the chemical reactivity. Here we report a novel and facile Nb(4+)-assisted strategy for the in situ growth of highly dispersed Pd nanoparticles (NPs) on monolayer HNb3O8 nanosheets (HNb3O8 NS) constituting a 2D Pd/HNb3O8 NS heterostructure composite without using extra reducing agents and stabilizing agents...
September 22, 2017: Nanoscale
https://www.readbyqxmd.com/read/28936850/-protective-effects-of-schizonepeta-volatile-oil-on-endotoxin-poisoning-induced-by-lipopolysaccharide-in-mice
#13
Tao-Qun Wen, Wen-Tao Sang, Feng Xu, Feng Wang, Nan Zeng
In order to study the protective effects of Schizonepeta volatile oil (Sto)on endotoxin poisoning mice, and the relatively content of each chemical osubstance in Schizonepeta volatile oil was measured using GC-MS. The mare C57BL/6J mice were randomly divided into five groups including the normal group, model group, dexamethasone group (5 mg•kg⁻¹), and Sto (0.226 and 0.452 g•kg⁻¹, respectively) groups. The dexamethasone group was given the drugs once time by intraperitoneal injection on the 5th day, while the other mice were given drugs by oral administration once a day for 5 days...
December 2016: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
https://www.readbyqxmd.com/read/28936577/highly-efficient-electro-oxidation-catalyst-under-ultra-low-voltage-for-degradation-of-aspirin
#14
Xiaolei Kang, Wei Sun, Limei Cao, Ji Yang
A novel cryptomelane-Ir (cry-Ir) electrode is prepared for Ir to enter into the cryptomelane (named as cry-Mn) structure and used for aspirin degradation. This catalyst can efficiently reduce the Ir usage from 85 to 34%. Also, the onset potential of cry-Ir is about 1.40 V and the over potential is about 0.34 V at 10 mA cm(-2), indicating that cry-Ir has an excellent oxygen evolution reaction (OER) activity to produce oxidizing species and can decrease electrolytic voltage during the electro-oxidation process...
September 22, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28936336/cyclohexa-1-4-dienes-in-transition-metal-free-ionic-transfer-processes
#15
REVIEW
Sebastian Keess, Martin Oestreich
Safe- and convenient-to-handle surrogates of hazardous chemicals are always in demand. Recently introduced cyclohexa-1,4-dienes with adequate substitution fulfil this role as El(+)/H(-) equivalents in B(C6F5)3-catalysed transfer reactions of El-H to π- and σ-donors (C 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 C/C 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 C and CO/CN)...
July 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28936331/double-c-h-bond-activation-of-acetylene-by-atomic-boron-in-forming-aromatic-cyclic-hbc2bh-in-solid-neon
#16
Jiwen Jian, Wei Li, Xuan Wu, Mingfei Zhou
The organo-boron species formed from the reactions of boron atoms with acetylene in solid neon are investigated using matrix isolation infrared spectroscopy with isotopic substitutions as well as quantum chemical calculations. Besides the previously reported single C-H bond activation species, a cyclic-HBC2BH diboron species is formed via double C-H bond activation of acetylene. It is characterized to have a closed-shell singlet ground state with planar D2h symmetry. Bonding analysis indicates that it is a doubly aromatic species involving two delocalized σ electrons and two delocalized π electrons...
June 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28935878/old-yellow-enzyme-homologues-in-mucor-circinelloides-expression-profile-and-biotransformation
#17
Alice Romagnolo, Federica Spina, Anna Poli, Sara Risso, Bianca Serito, Michele Crotti, Daniela Monti, Elisabetta Brenna, Luisa Lanfranco, Giovanna Cristina Varese
The reduction of C=C double bond, a key reaction in organic synthesis, is mostly achieved by traditional chemical methods. Therefore, the search for enzymes capable of performing this reaction is rapidly increasing. Old Yellow Enzymes (OYEs) are flavin-dependent oxidoreductases, initially isolated from Saccharomyces pastorianus. In this study, the presence and activation of putative OYE enzymes was investigated in the filamentous fungus Mucor circinelloides, which was previously found to mediate C=C reduction...
September 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28935769/mof-derived-cobalt-nanoparticles-catalyze-a-general-synthesis-of-amines
#18
Rajenahally V Jagadeesh, Kathiravan Murugesan, Ahmad S Alshammari, Helfried Neumann, Marga-Martina Pohl, Jörg Radnik, Matthias Beller
The development of base metal catalysts for the synthesis of pharmaceutically relevant compounds remains an important goal of chemical research. Here, we report that cobalt nanoparticles encapsulated by a graphitic shell are broadly effective reductive amination catalysts. Their convenient and practical preparation entailed template assembly of cobalt-diamine-dicarboxylic acid metal organic frameworks on carbon and subsequent pyrolysis under inert atmosphere. The resulting stable and reusable catalysts were active for synthesis of primary, secondary, tertiary and N-methylamines (>140 examples)...
September 21, 2017: Science
https://www.readbyqxmd.com/read/28935566/construction-of-protein-functionalized-virus-like-particles-of-parvovirus-b19
#19
Ismael Bustos-Jaimes, Ricardo Arturo Soto-Román, Isabel Alejandra Gutiérrez-Landa, Josefina Valadez-García, Carla Lizbeth Segovia-Trinidad
Decoration of virus-like particles (VLPs) expands the repertory of functions these particles can display. In the last years, VLPs have successfully been used as scaffolds to present different molecules, frequently through the specific reaction of chemical groups on the surface of the particles, or by protein engineering when the presentation of peptides or proteins is the primary goal. VLPs of parvovirus B19 (B19V), have been previously produced in vitro and its stability and ability to assemble into hybrid particles composed of wild-type and chimeric proteins evidenced their potential as research tools...
September 18, 2017: Journal of Biotechnology
https://www.readbyqxmd.com/read/28935406/fate-and-chemical-speciation-of-antimony-sb-during-uptake-translocation-and-storage-by-rye-grass-using-xanes-spectroscopy
#20
Ying Ji, Géraldine Sarret, Rainer Schulin, Susan Tandy
Antimony (Sb) is a contaminant of increased prevalence in the environment, but there is little knowledge about the mechanisms of its uptake and translocation within plants. Here, we applied for the synchrotron based X-ray absorption near-edge structure (XANES) spectroscopy to analyze the speciation of Sb in roots and shoots of rye grass (Lolium perenne L. Calibra). Seedlings were grown in nutrient solutions to which either antimonite (Sb(III)), antimonate (Sb(V)) or trimethyl-Sb(V) (TMSb) were added. While exposure to Sb(III) led to around 100 times higher Sb accumulation in the roots than the other two treatments, there was no difference in total Sb in the shoots...
September 18, 2017: Environmental Pollution
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