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Rahul Jain, Ranga Pitchumani
Superhydrophobic surfaces have myriad industrial applications, yet their practical utilization has been limited by their poor mechanical durability and longevity. We present a low cost, facile process to develop superhydrophobic copper based coatings via electrodeposition route, that addresses this limitation. Through electrodeposition, a stable, multiscale, cauliflower shaped fractal morphology was obtained and upon modification by stearic acid, the prepared coatings show extreme water repellency with contact angle of 162 ± 2(o) and roll-off angle of about 3(o)...
October 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Songjie Yu, Hui Leng Sang, Shaozhong Ge
We report an asymmetric copper-catalyzed alkylation of quinoline N-oxides with chiral Cu-alkyl species generated by migratory insertion of vinylarene into a chiral Cu-H complex. A variety of quinoline N-oxides and vinylarenes underwent this Cu-catalyzed enantioselective alkylation reaction, yielding the corresponding chiral alkylated N-heteroarenes in high isolated yields with high to excellent enantioselectivities. This enantioselective protocol represents the first general and practical approach to access a wide range of chiral alkylated quinolines...
October 16, 2017: Angewandte Chemie
Ute Wild, Florian Schön, Hans-Jörg Himmel
Herein we report the first examples for the use of redox-active guanidines as catalysts in the green oxidation of organic molecules with dioxygen. In one half-reaction, the oxidized state of the redox-active guanidine is converted to the reduced, protonated state, thereby enabling dehydrogenative oxidation of the substrate (3,5-ditertbutylcatechol → o-benzoquinone, benzoin → benzil, and 2,4-ditertbutylphenol → biphenol). In the other half-reaction, efficient re-oxidation of the guanidine to the oxidized state is achieved with dioxygen in the presence of a copper catalyst...
October 18, 2017: Angewandte Chemie
Chih-Hung Chou, Basker Rajagopal, Chien-Fu Liang, Kuan-Lin Chen, Dun-Yuan Jin, Hsing-Yin Chen, Hsiu-Chung Tu, Yo-Ying Shen, Po-Chiao Lin
In this study, a series of variously substituted 2,3-dihydroquinolin-4-imines (DQIs) were synthesized from N-substituted propargylanilines by copper(I)-catalyzed annulation. The approach adopted in this study under mild, effective conditions exhibited broad substrate tolerance, particularly for functional groups substituted on anilines. Most of the DQI derivatives synthesized under optimal conditions were obtained in good isolated yields of 63-88%. 2,3-Dihydroquinolinimine thus obtained was easily converted to important structures like 2,3-dihydroquinolone and tetrahydrobenzodiazepin-5-one, confirming the importance of this strategy in constructing various heterocycles...
October 18, 2017: Chemistry: a European Journal
Torben Steenbock, Carmen Herrmann
Understanding (super-)exchange coupling between local spins is an important task in theoretical chemistry and solid-state physics. We show that a Green's-function approach introduced earlier (Liechtenstein et al., J. Phys. F 1984, 14, L125; Steenbock et al., J. Chem. Theory Comput. 2015, 11, 5651) can be used for analyzing exchange coupling pathways in an automated fashion rather than by visual inspection of molecular orbitals. We demonstrate the capabilities of this approach by comparing it to previously published pathway analyses for hydroxy-bridged dinuclear copper complexes and an oxo-bridged dinuclear manganese complex, and employ it for discriminating between through-space and through-bond pathways in a naphthalene-bridged bisnickelocene complex...
October 17, 2017: Journal of Computational Chemistry
Jessica R Holan, Catherine K King, Andrew R Davis
The development of environmental guidelines in the Antarctic and subantarctic is essential, as expansion of research, tourism and fishing places these regions at increasing risk of contamination. Due to unique conditions in these areas, region specific guidelines are required, however there are currently insufficient data to do this. To develop the most appropriate environmental guidelines, data from the most sensitive life stages of a species should be included to ensure effective protection throughout its life cycle...
October 17, 2017: Environmental Toxicology and Chemistry
Putri Fadhillah Nugraha, Nandy Putra, Bambang Ariantara, Muhammad Amin
Non-electric infant incubators are needed in remote areas that have no access to electricity to reduce infant mortality nationwide. In previous studies, non-electric infant incubators have been developed using phase change material of beeswax as the heating element. This study aims to improve the performance of beeswax non-electric infant incubator to obtain a more reliable and practical one. The design of the original beeswax cartridge in the form of copper boxes was modified into tubes of stainless steel...
October 18, 2017: Journal of Medical Engineering & Technology
Fellippo Ramos Verri, Marlice Hayumi Theles Okumura, Cleidiel Aparecido Araujo Lemos, Daniel Augusto de Faria Almeida, Victor Eduardo de Souza Batista, Ronaldo Silva Cruz, Hiskell Francine Fernandes Oliveira, Eduardo Piza Pellizzer
The aim of this study was to evaluate different materials for restoration of teeth without ferrule by three-dimensional (3D) finite element analysis (FEA). Five models simulating the maxillary central incisor and surrounding bone were simulated according to the type of post: glass fibre post (GFP) or cast metal post (CMP) with different alloys such as gold (Au), silver-palladium (AgPd), copper-aluminum (CuAl) and nickel-chromium (NiCr). Models were designed using Invesalius and Rhinoceros. FEAs were made using FEMAP and NeiNastran, with an applied axial force of 100 N and oblique occlusal load at 45°...
October 18, 2017: Journal of Medical Engineering & Technology
Hyo-Min Kim, Jeonggi Kim, Sin-Young Cho, Jin Jang
We report the solution processed metal-oxide p-n junction, Li doped CuO (Li:CuO) and Li doped ZnO (Li:ZnO), as a charge generation junction (CGJ) in quantum-dot light-emitting diode (QLED) at reverse bias. Efficient charge generation is demonstrated in a stack of air annealed Li:CuO and Li:ZnO layers in QLEDs. Air annealing of Li:ZnO on Li:CuO turns out to be a key process to decrease the oxygen vacancy (Vo) and to increase the copper(II) oxide (CuO) fraction at the Li:CuO/Li:ZnO interface for efficient charge generation...
October 18, 2017: ACS Applied Materials & Interfaces
J Fritzsche, D Denysenko, M Grzywa, D Volkmer
The synthesis and crystal structure of the mixed-valent perfluorinated metal-organic framework (Me2NH2)[CFA-13] (Coordination Framework Augsburg University-13), (Me2NH2)[CuCu(tfpc)4] (H2-tfpc = 3,5-bis(trifluoromethyl)-1H-pyrazole-4-carboxylic acid) is described. The copper-containing MOF crystallizes in the monoclinic crystal system within the space group P21/n (no. 14) and the unit cell parameters are as follows: a = 22.3887(19), b = 13.6888(8), c = 21.1804(13) Å, β = 90.495(3)°, V = 6491.0(8) Å(3). (Me2NH2)[CFA-13] features a porous 3-D structure constructed from two types of secondary building units (SBUs)...
October 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Sebastian Bette, Reinhard K Kremer, Gerhard Eggert, Chiu C Tang, Robert E Dinnebier
Known synthesis approaches for basic copper(ii) acetates, the main components of historic verdrigis pigments were reinvestigated and revealed to be partially irreproducible. A modification of the reaction conditions led to the successful and reproducible synthesis of the 1-2-0 phase (Cu3(CH3COO)2(OH)4 = 1Cu(CH3COO)2·2Cu(OH)2·0H2O). The phase composition was derived from elemental and thermal analysis and confirmed by the crystal structure solution using synchrotron X-ray powder diffraction (XRPD) data. The 1-2-0 phase crystallises in space group Pbca with lattice parameters of a = 20...
October 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Hong Chen, Hua Lin, Yi Liu, Xin-Tao Wu, Li-Ming Wu
The chemistry of copper-based chalcogenides has received considerable attention due to their diverse structures and potential applications in the area of thermoelectric (TE) materials. In this communication, a series of spinel-type Cu4Mn2Te4-based samples have been successfully prepared and their high TE performances are attributed to the enhanced power factor and low thermal conductivity via the synergistic effect of Te deficiency and Cl doping. Consequently, a maximum TE figure of merit (ZT) of ∼0.4 was achieved for the Cu4Mn2Te3...
October 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Karunamay Majee, Jully Patel, Babulal Das, Sumanta Kumar Padhi
The binuclear copper complex [Cu(DQPD)]2 (where DQPD = deprotonated N(2),N(6)-di(quinolin-8-yl)pyridine-2,6-dicarboxamide (DQPDH2)) was synthesised and characterised by various spectroscopic as well as electrochemical techniques. The binuclear copper complex was converted into a mononuclear one by the addition of 2 equivalents of pTsOH into [Cu(DQPD)]2. The interconversion between the dimer and monomer complex was studied through UV-Vis spectroscopy and cyclic voltammetry. The mononuclear copper complex showed high catalytic activity towards electrochemical proton reduction using acetic acid as the external proton source in 95 : 5 (v/v) DMF/H2O...
October 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Robert L Harniman, Daniela Plana, George H Carter, Kieren A Bradley, Mervyn J Miles, David J Fermín
The real-time visualization of stochastic nucleation events at electrode surfaces is one of the most complex challenges in electrochemical phase formation. The early stages of metal deposition on foreign substrates are characterized by a highly dynamic process in which nanoparticles nucleate and dissolve prior to reaching a critical size for deposition and growth. Here, high-speed non-contact lateral molecular force microscopy employing vertically oriented probes is utilized to explore the evolution of hydration layers at electrode surfaces with the unprecedented spatiotemporal resolution, and extremely low probe-surface interaction forces required to avoid disruption or shielding the critical nucleus formation...
October 17, 2017: Nature Communications
Sai-Nan Guo, Jia-Lang Zheng, Shuang-Shuang Yuan, Qing-Ling Zhu
In this study, female zebrafish (Danio rerio) were exposed to 26°C or 34°C, 0 or 197μg/L cadmium (Cd), singly or in combination for 7days. Multiple stress-related indicators were evaluated in the liver. Mortality, lipid peroxidation (LPO) and ultrastructural damage increased significantly by Cd exposure alone, and were not affected by heat alone. Interestingly, the combined exposure increased LPO, ultrastructural damage, and mortality compared with Cd exposure alone. The results indicated that elevated temperature increased Cd toxicity, which could be explained by several reasons...
October 14, 2017: Science of the Total Environment
Jiannan Gao, Chuwen Lan, Qian Zhao, Bo Li, Ji Zhou
An electrically controlled metamaterial perfect absorber (MPA) based on Mie resonance is demonstrated experimentally and modeled numerically. A ceramic dielectric cube is adhered to a specially shaped thin copper film sputtered on a quartz plate. By passing direct current (DC) through the film, the temperature of the cube can be varied, resulting in changing the cube's permittivity and shifting the absorption resonance frequency. The frequency increases on heating and the absorption is over 99% throughout the tuning range...
September 18, 2017: Optics Express
Qingfeng Li, Anne Patricia Alloncle, David Grojo, Philippe Delaporte
When the energy of a short laser pulse is localized in a fluid material, a flow motion is induced that can lead to the generation of free-surface jets. This nozzle-free jetting process is exploited to print conductive materials, typically metal nanoparticle inks, but this approach remains limited to the transfer of low viscosity fluids with a minimum feature size of few micrometers. We introduce a dual-laser method to achieve reproducible high-aspect-ratio jets from thin solid films. A first laser irradiation induces the melting of copper thin films and a second synchronized short pulse irradiation initiates the jetting process...
October 2, 2017: Optics Express
Yuguang Wang, Kai Li, Xinhua Chen, Hongbo Zhou
The microbial diversity and dynamics in the leachates and on the ore surfaces of different depth of the column were analyzed during bioleaching of low grade copper sulfide at different pH, after inoculation with the same inoculum containing mesophiles and moderate thermophiles. The results indicate that low pH was beneficial to enhance copper extraction. The highest copper extraction (86%) was obtained when pH was controlled at 1.0-1.5. The microbial structures on the ore surfaces were independent of community structures in the leachate, even at the top portion of column...
October 7, 2017: Bioresource Technology
Maria Maleva, Galina Borisova, Nadezhda Chukina, Adarsh Kumar
In the present study, two fresh water plant species Egeria densa (Planch.) Casp. and Ceratophyllum demersum L. were subjected to separate and combined action of urea (2mМ) and metals (Ni and Cu, 10μM) to investigate the phytoremediation potential of these two submerged macrophytes during short-term experiments (48h). Both submerged macrophytes demonstrated high accumulative potential for Ni and Cu (average bioconcentration factors were 2505 for Ni and 3778 for Cu). The urea (2 mM) was not significantly toxic for studied plant species...
October 14, 2017: Ecotoxicology and Environmental Safety
Juan Jesús Velasco Vélez, Katarzyna Skorupska, Elias Frei, Yu-Cheng Huang, Chung Li Dong, Bing-Jian Su, Cheng-Jhih Hsu, Hung-Yu Chou, Jin-Ming Chen, Peter Strasser, Robert Schloegl, Axel Knop-Gericke, ChengHao Chuang
The electrodeposition nature of copper on a gold electrode in a 4.8 pH CuSO4 solution was inquired using X-ray absorption spectroscopy, electrochemical quartz crystal microbalance and thermal desorption spectroscopy techniques. Our results point out that the electrodeposition of copper prompts the formation of stable oxi-hydroxide species with a formal oxidation state Cu+ without the evidence of metallic copper formation (Cu0). Moreover, the subsequent anodic polarization of Cu2Oaq yields the formation of CuO, in the formal oxidation state Cu2+, which is dissolved at higher anodic potential...
October 17, 2017: Journal of Physical Chemistry. B
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