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https://www.readbyqxmd.com/read/29160872/zinc-ii-cobalt-ii-and-manganese-ii-networks-with-phosphoserine-ligand-synthesis-crystal-structures-and-magnetic-and-proton-conductivity-properties
#1
J Vallejo, I R Salcedo, R M P Colodrero, A Cabeza, A Switlicka, J Cano, M Viciano-Chumillas
A series of zinc(ii), cobalt(ii) and manganese(ii) coordination networks with phosphoserine ligand (H3PSer) are synthesized and characterized. Whereas in compounds 1 and 2 with the general formula [M(HPser)]n [M = Zn (1) and Co (2)], the metal(ii) ion presents a tetrahedral geometry, in [Co(HPSer)(H2O)2]n (3) and [Mn(HPSer)(H2O)]n (4), the metal(ii) ions are in a distorted octahedral geometry. The 3D frameworks are formed by inorganic layers built up from MO4 or MO6 polyhedra and phosphate groups. These layers are linked by the carboxylate groups of the phosphoserine ligand...
November 21, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29160057/effective-and-durable-co-single-atomic-co-catalysts-for-photocatalytic-hydrogen-production
#2
Qi Zhao, Weifeng Yao, Cunping Huang, Qiang Wu, Qunjie Xu
This research reports for the first time that single cobalt atoms anchored nitrogen-doped graphene (Co-NG) can serve as a highly effective and durable cocatalyst for visible light photocatalytic hydrogen production from water. Results show that under identical conditions the hydrogen production rate (1382 µmol/h) for 0.25 wt.% Co-NG loaded CdS photocatalyst (0.25 wt.% Co-NG/CdS) is 3.42 times greater than that of nitrogen-doped graphene (NG) loaded CdS photocatalyst (NG/CdS) and about 1.3 times greater than the greatest hydrogen production rate (1077 µmol/h) for 1...
November 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29159348/hydrogen-evolution-from-water-based-on-plasmon-induced-charge-separation-at-a-tio2-au-nio-pt-system
#3
Kun-Che Kao, Yoshinori Kuroiwa, Hiroyasu Nishi, Tetsu Tatsuma
Metal-semiconductor plasmonic nanostructures are capable of converting light energy through plasmon-induced charge separation (PICS), providing fruitful new strategies to utilize solar energy in various fields, including photocatalysis. Here, we enhance the PICS efficiencies for hydrogen evolution from water at a Pt cathode coupled with a TiO2/Au photoanode by coating the TiO2/Au with a p-type NiO layer on which a Pt co-catalyst is deposited. PICS occurs at the Au-TiO2 interface under visible light. The electrons injected from the Au nanoparticles into TiO2 are transported to the Pt cathode and cause hydrogen evolution from water, the action spectrum of which matches the plasmonic extinction spectrum of the Au nanoparticles...
November 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29153087/a-fluorescence-aptasensor-based-on-two-dimensional-sheet-metal-organic-frameworks-for-monitoring-adenosine-triphosphate
#4
Xiao-Man Hai, Nan Li, Ke Wang, Zhi-Qi Zhang, Jing Zhang, Fu-Quan Dang
In the present study, a facile fluorescence aptasensor based on two-dimensional sheet metal-organic frameworks of N,N-bis(2-hydroxyethyl)dithiooxamidato copper(II) (H2dtoaCu) was developed for the sensitive detection of adenosine triphosphate (ATP). The sensing mechanism was based on the noncovalent interaction between FAM-labeled (fluorescein amidite) ATP aptamers and H2dtoaCu. In the absence of ATP, the FAM-labeled aptamer readily adsorbs onto H2dtoaCu, mainly via π-π stacking and hydrogen bond interactions between the nucleotide bases and the H2dtoaCu surface, leading to the reduction of fluorescence intensity of the FAM by photoinduced electron transfer (PET)...
January 15, 2018: Analytica Chimica Acta
https://www.readbyqxmd.com/read/29152341/crystal-structure-of-4-4-bipyridyl-%C3%AE%C2%BAn-bis-n-2-hydroxy-ethyl-n-iso-propyl-dithio-carbamato-%C3%AE%C2%BA-2-s-s-zinc-ii-4-4-bipyridyl-2-1-and-its-isostructural-cadmium-ii-analogue
#5
Yee Seng Tan, Edward R T Tiekink
The title structures, [M(C6H12NOS2)2(C10H8N2)]·0.5C10H8N2, for M = Zn, (I), and Cd, (II), feature terminally bound 4,4'-bipyridyl ligands and non-coordinating 4,4'-bi-pyridyl mol-ecules, with the latter disposed about a centre of inversion. The coordination geometry about the metal atom is defined by two non-symmetrically chelating di-thio-carbamate ligands and a pyridyl N atom. The NS4 donor sets are distorted but, approximate to trigonal bipyramidal in each case. In the crystal, hy-droxy-O-H⋯O(hy-droxy) and hy-droxy-O-H⋯N(pyrid-yl) hydrogen bonds between the zinc-containing mol-ecules lead to a supra-molecular layer parallel to (100)...
November 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/29152332/crystal-structure-of-poly-di-aqua-bis-%C3%AE-5-benzene-1-3-di-carboxyl-ato-n-n-di-methyl-formamide-cadmium-ii-disodium-i
#6
Matimon Sangsawang, Kittipong Chainok, Nanthawat Wannarit
The title compound, [CdNa2(C8H4O4)2(C3H7NO)(H2O)2] n or [CdNa2(1,3-bdc)2(DMF)(H2O)2] n , is a new Cd(II)-Na(I) heterobimetallic coordination polymer. The asymmetric unit consists of one Cd(II) atom, two Na(I) atoms, two 1,3-bdc ligands, two coordinated water mol-ecules and one coordinated DMF mol-ecule. The Cd(II) atom exhibits a seven-coordinate geometry, while the Na(I) atoms can be considered to be penta-coordinate. The metal ions and their symmetry-related equivalents are connected via chelating-bridging carboxyl-ate groups of the 1,3-bdc ligands to generate a three-dimensional framework...
November 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/29152035/direct-visualization-of-au-atoms-bound-to-tio2-110-o-vacancies
#7
Andrew Mellor, David Humphrey, Chi M Yim, Chi L Pang, Hicham Idriss, Geoff Thornton
Au nanoparticles supported on reducible metal oxide surfaces are known to be active catalysts for a number of reactions including CO oxidation and hydrogen production. The exact choice of a metal oxide support has been shown to have a marked impact on activity, suggesting that interactions between Au and the support play a key role in catalysis. For TiO2, a model substrate for Au catalysis, it had been thought that bridging oxygen vacancies are involved in binding Au atoms to the (110) surface based on indirect evidence...
November 9, 2017: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
https://www.readbyqxmd.com/read/29150441/co-ii-and-ni-ii-binding-of-the-escherichia-coli-transcriptional-repressor-rcnr-orders-its-n-terminus-alters-helix-dynamics-and-reduces-dna-affinity
#8
Hsin-Ting Huang, Cedric E Bobst, Jeffrey S Iwig, Peter T Chivers, Igor A Kaltashov, Michael J Maroney
RcnR, a transcriptional regulator in Escherichia coli, derepresses the expression of the export proteins RcnAB upon binding Ni(II) or Co(II). Lack of structural information has precluded elucidation of the allosteric basis for the decreased DNA affinity in RcnR's metal-bound states. Here, using hydrogen-deuterium exchange coupled with MS (HDX-MS), we probed the RcnR structure in the presence of DNA, the cognate metal ions Ni(II) and Co(II), or the noncognate metal ion Zn(II). We found that cognate metal binding altered the flexibility from the N-terminus through helix 1 and modulated the RcnR-DNA interaction...
November 17, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29149555/mapping-the-reactions-in-a-single-zero-valent-iron-nanoparticle
#9
Lan Ling, Xiao-Yue Huang, Meirong Li, Wei-Xian Zhang
Nanoscale zero-valent iron (nZVI) posseses unique functionalities for metal-metalloid removal and sequestration. So far, direct evidence on the heavy metal-iron reactions in the solid phase is still limited due to low concentration of heavy metals and small size of nanoparticles. In this work, angstrom-resolution spectral mappings on the reactions of nZVI with chromate, arsenate, nickel, silver, cesium, and zinc ions are presented. This work was achieved with spherical aberration-corrected scanning transmission electron microscopy integrated with high-sensitivity X-ray energy-dispersive spectroscopy scanning transmission electron microscopy (XEDS-STEM)...
November 17, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/29149471/polyaniline-derived-n-doped-carbon-coated-cobalt-phosphide-nanoparticles-deposited-on-n-doped-graphene-as-an-efficient-electrocatalyst-for-hydrogen-evolution-reaction
#10
Jingwen Ma, Min Wang, Guangyu Lei, Guoliang Zhang, Fengbao Zhang, Wenchao Peng, Xiaobin Fan, Yang Li
The development of highly efficient and durable non-noble metal electrocatalysts for the hydrogen evolution reaction (HER) is significant for clean and renewable energy research. This work reports the synthesis of N-doped graphene nanosheets supported N-doped carbon coated cobalt phosphide (CoP) nanoparticles via a pyrolysis and a subsequent phosphating process by using polyaniline. The obtained electrocatalyst exhibits excellent electrochemical activity for HER with a small overpotential of -135 mV at 10 mA cm(-2) and a low Tafel slope of 59...
November 17, 2017: Small
https://www.readbyqxmd.com/read/29148984/supercritical-diethylamine-facilitated-loading-of-ultrafine-ru-particles-on-few-layer-graphene-for-solvent-free-hydrogenation-of-levulinic-acid-to-%C3%AE-valerolactone
#11
Tao Hengcong, Jingjing Ding, Chao Xie, Yunnan Gao, Jinliang Song, Zhenyu Sun
We demonstrate a facile and versatile method to grow Ru particles uniformly on pristine few-layer graphene (FLG) in supercritical diethylamine. In particular, a large number of Ru subnanometer clusters less than 1.0 nm were observed. The particle size can be tuned by manipulating the loading content of Ru and controlling the reaction temperature. The resulting Ru/FLG showed remarkably high activity, selectivity, and reusability towards the hydrogenation of levulinic acid to γ-valerolactone. This method is flexible, and can be extended to the synthesis of a variety of other ultrafine metal particles supported on FLG...
November 17, 2017: Nanotechnology
https://www.readbyqxmd.com/read/29148779/hydrogen-uptake-on-coordinatively-unsaturated-metal-sites-in-vsb-5-revisited-strong-binding-affinity-leading-to-high-temperature-d2-h2-selectivity
#12
Amit Sharma, Keith V Lawler, Jarod J Wolffis, Christopher T Eckdahl, Cooper S McDonald, Jesse L C Rowsell, Stephen A Fitzgerald, Paul M Forster
We examine the adsorption of hydrogen and deuterium into the nanoporous nickel phosphate, VSB-5. Based on gas sorption analysis, VSB-5 exhibits one of the highest measured H2 heats of adsorption (HOA) for hydrogen (16 kJ/mol) yet reported. This high HOA is consistent with an unusually large redshift in the Q(1) and Q(0) hydrogen vibrational modes as measured with in situ IR spectroscopy. The HOA for D2 is measured to be 2 kJ/mol higher than for H2. Ideal Adsorbed Solution Theory analysis of H2 and D2 isotherms provides selectivities above 4 for deuterium at 140 K, suggesting that VSB-5 is a promising adsorbent for pressure-swing adsorption type separations of hydrogen isotopes...
November 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29148746/keto-enol-tautomerization-triggers-an-electrophilic-aldehyde-deformylation-reaction-by-a-nonheme-manganese-iii-peroxo-complex
#13
Fabián G Cantú Reinhard, Prasenjit Barman, Gourab Mukherjee, Jitendra Kumar, Deep Kumar, Devesh Kumar, Chivukula V Sastri, Sam P de Visser
Oxygen atom transfer by high-valent enzymatic intermediates remains an enigma in chemical catalysis. In particular, manganese is an important first-row metal involved in key biochemical processes including the biosynthesis of mo-lecular oxygen (through the photosystem II complex) and biodegradation of toxic superoxide to hydrogen peroxide by superoxide dismutase. Biomimetic models of these biological systems have been developed to gain understanding on the structure and properties of short-lived intermediates but also with the aim to create environmentally benign oxidants...
November 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29148736/formation-of-metal-cyanide-complexes-in-deliquescent-airborne-particles-a-new-possible-sink-for-hcn-in-urban-environments
#14
Chiara Giorio, Daniele Marton, Gianni Formenton, Andrea Tapparo
Hydrogen cyanide is a ubiquitous gas in the atmosphere and a biomass burning tracer. Reactive gasses can be adsorbed onto aerosol particles where they can promote heterogeneous chemistry. In the present study, we report for the first time on the measurement and speciation of cyanides in atmospheric aerosol. Filter samples were collected at an urban background site in the city center of Padua (Italy), extracted and analyzed with headspace gas chromatography and nitrogen-phosphorous detection. The results showed that strongly bound cyanides were present in all aerosol samples at a concentration ranging between 0...
November 17, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/29148234/visible-light-mediated-metal-free-hydrosilylation-of-alkenes-through-selective-hydrogen-atom-transfer-for-si-h-activation
#15
Rong Zhou, Yi Yiing Goh, Haiwang Liu, Hairong Tao, Lihua Li, Jie Wu
Although developments on the transition-metal-catalyzed hydrosilylation of alkenes have achieved great progress over the past several decades, metal-free hydrosilylation is still rare and highly desirable. Herein, we report a convenient visible-light-driven metal-free hydrosilylation of both electron-deficient and electron-rich alkenes via selective hydrogen atom transfer for Si-H activation. By the synergistic combination of an organo-photocatalyst 4CzIPN and quinuclidin-3-yl acetate catalyst, the hydrosilylation of electron-deficient alkenes exclusively occurred with Si-H activation...
November 16, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/29146810/catalytic-molten-metals-for-the-direct-conversion-of-methane-to-hydrogen-and-separable-carbon
#16
D Chester Upham, Vishal Agarwal, Alexander Khechfe, Zachary R Snodgrass, Michael J Gordon, Horia Metiu, Eric W McFarland
Metals that are active catalysts for methane (Ni, Pt, Pd), when dissolved in inactive low-melting temperature metals (In, Ga, Sn, Pb), produce stable molten metal alloy catalysts for pyrolysis of methane into hydrogen and carbon. All solid catalysts previously used for this reaction have been deactivated by carbon deposition. In the molten alloy system, the insoluble carbon floats to the surface where it can be skimmed off. A 27% Ni-73% Bi alloy achieved 95% methane conversion at 1065°C in a 1.1-meter bubble column and produced pure hydrogen without CO2 or other by-products...
November 17, 2017: Science
https://www.readbyqxmd.com/read/29146332/micro-oxygenation-does-not-eliminate-hydrogen-sulfide-and-mercaptans-from-wine-it-simply-shifts-redox-and-complex-related-equilibria-to-reversible-oxidized-species-and-complexed-forms
#17
Eduardo Vela, Purificación Hernandez-Orte, Ernesto Franco-Luesma, Vicente Ferreira
This work seeks to assess the effects of micro-oxygenation (MOX) on the present and potential levels of Volatile Sulfur Compounds (VSCs) of wine. With such purpose, three red wines with a tendency to develop sulfury off-odors were subjected to three different MOX conditions (4.4-20mg/L delivered at 0.05 or 0.2mg/L/day). Samples were further subjected to Accelerated Reductive aging (AR) and analyzed for free and Brine Releasable (BR) VSCs and redox potential. Although MOX induced strong decreases in the levels of all free VSCs, hardly affected the ability of the wine to release back hydrogen sulfide and other mercaptans during AR-aging...
March 15, 2018: Food Chemistry
https://www.readbyqxmd.com/read/29144751/dendrimer-stabilized-metal-nanoparticles-as-efficient-catalysts-for-reversible-dehydrogenation-hydrogenation-of-n-heterocycles
#18
Christophe V Deraedt, Rong Ye, Walter Ralston, F Dean Toste, Gabor A Somorjai
Nanoparticles (Pd, Pt, Rh) stabilized by G4OH PAMAM dendrimers and supported in SBA-15 (MNPs/SBA-15 with M= Pd, Pt, Rh) were efficiently used as catalysts in the acceptorless dehydrogenation of tetrahydroquinoline/indoline derivatives in toluene (release of H2) at 130 °C. These catalysts are air stable, very active, robust, and recyclable during the process. The reverse hydrogenation reaction of quinoline derivatives (H2 storage) was also optimized and successfully performed in presence of the same catalysts in toluene at 60 °C under only 1 atmosphere of hydrogen gas...
November 16, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29144606/mesoporous-nickel-and-cobalt-based-oxides-nanorods-catalytic-effects-on-improving-libh4-dehydrogenation-properties
#19
Lei Zang, Qiuyu Zhang, Li Li, Yike Huang, Xiaoya Chang, Lifang Jiao, Huatang Yuan, Yijing Wang
Lithium borohydride (LiBH4) with a theoretical hydrogen storage capacity of 18.5 wt% has attracted intense interest as a high-density hydrogen storage material. However, high dehydrogenation temperatures and limited kinetics restrict its practical applications. In this study, the mesoporous nickel- and cobalt-based oxides nanorods (NiCo2O4, Co3O4 and NiO) were controlled synthesized by hydrothermal method and mixed with LiBH4 by ball milling. It is found that the dehydrogenation properties of LiBH4 are remarkably enhanced by doping the as-synthesized metal oxides nanorods...
November 16, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29143834/cobalt-nickel-and-iron-complexes-of-8-hydroxyquinoline-di-2-picolyl-amine-for-light-driven-hydrogen-evolution
#20
Nadia Alessandra Carmo Dos Santos, Mirco Natali, Elena Badetti, Klaus Wurst, Giulia Licini, Cristiano Zonta
Novel cobalt, nickel, and iron complexes based on the pentadentate 8-hydroxyquinoline-di(2-picolyl)amine ligand were synthesized and thoroughly characterized. X-ray structures of both the cobalt and iron complexes were also obtained, showing the tendency to adopt a pseudo-octahedral geometry by coordination of an additional sixth ligand. These metal complexes were then studied as potential hydrogen-evolving catalysts (HECs) under both electrochemical and light-driven conditions. In particular, two different photochemical systems were tested involving either Ru(bpy)3(2+)/ascorbic acid or Ir(ppy)2(bpy)(+)/TEA sensitizer/sacrificial donor couples...
November 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
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