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Siegfried R Waldvogel, Sebastian Lips, Dieter Schollmeyer, Robert Franke
A novel strategy for the efficient synthesis of biaryls consisting of a benzothiophene and phenol moiety is reported. These heterobiaryls are of utmost interest for pharmaceutical, biological, and high-performance optoelectronic applications. By a metal- and reagent-free, sustainable, electrosynthetic and highly efficient method, 2-(hydroxyphenyl)- or 3-(hydroxyphenyl)benzo[b]thiophenes are regioselectively obtained. The described one-step synthesis is easy to conduct, scalable and inherently safe. The products are afforded in high yields up to 88% and exquisite selectivity...
August 13, 2018: Angewandte Chemie
Niankai Fu, Gregory S Sauer, Song Lin
This protocol describes an electrochemical synthesis of 1,2-diazides from alkenes. Organic azides are highly versatile intermediates for synthetic chemistry, materials, and biological applications. 1,2-Diazides are commonly reduced to form 1,2-diamines, which are prevalent structural motifs in bioactive natural products, therapeutic agents, and molecular catalysts. The electrochemical formation of 1,2-diazides involves the anodic generation of an azidyl radical from sodium azide, followed by two successive additions of this N-centered radical to the alkene, and is assisted by a Mn catalyst...
August 2018: Nature Protocols
Yoo Seok Lee, Seungwoo Baek, Hyeryeong Lee, Stacy Simai Reginald, Yeongeun Kim, Hyunsoo Kang, In-Geol Choi, In Seop Chang
Direct electron transfer (DET) between enzymes and electrodes is a key issue for practical use of bioelectrocatalytic devices as a bioenergy process, such as enzymatic electrosynthesis, biosensors, and enzyme biofuel cells. To date, based on the DET of bioelectrocatalysis, less than 1% of the calculated theoretical current was transferred to final electron acceptor due to energy loss at enzyme-electrode interface. This study describes the design and construction of a synthetic glucose dehydrogenase (GDH; α and γ subunits) combined with a gold-binding peptide at its amino or carboxy terminus for direct contact between enzyme and electrode...
August 15, 2018: ACS Applied Materials & Interfaces
Yansong Zhou, Fanglin Che, Min Liu, Chengqin Zou, Zhiqin Liang, Phil De Luna, Haifeng Yuan, Jun Li, Zhiqiang Wang, Haipeng Xie, Hongmei Li, Peining Chen, Eva Bladt, Rafael Quintero-Bermudez, Tsun-Kong Sham, Sara Bals, Johan Hofkens, David Sinton, Gang Chen, Edward H Sargent
The electrochemical reduction of CO2 to multi-carbon products has attracted much attention because it provides an avenue to the synthesis of value-added carbon-based fuels and feedstocks using renewable electricity. Unfortunately, the efficiency of CO2 conversion to C2 products remains below that necessary for its implementation at scale. Modifying the local electronic structure of copper with positive valence sites has been predicted to boost conversion to C2 products. Here, we use boron to tune the ratio of Cuδ+ to Cu0 active sites and improve both stability and C2 -product generation...
July 16, 2018: Nature Chemistry
Xiang Ren, Guanwei Cui, Liang Chen, Fengyu Xie, Qin Wei, Ziqi Tian, Xuping Sun
A highly attractive, but still a key challenge, is the development of earth-abundant electrocatalysts for efficient NH3 electrosynthesis via the N2 reduction reaction (NRR). In this communication, we report the development of a Mo2N nanorod as a highly efficient and selective NRR electrocatalyst for artificial N2 fixation in acidic electrolytes under ambient conditions. In 0.1 M HCl, this catalyst achieved a high Faradaic efficiency of 4.5% with a NH3 yield of 78.4 μg h-1 mgcat.-1 at -0.3 V vs. a reversible hydrogen electrode, thus outperforming most reported NRR electrocatalysts under ambient conditions and some under harsh conditions...
July 26, 2018: Chemical Communications: Chem Comm
Ke Huang, Jan Clausmeyer, Long Luo, Karalee Jarvis, Richard M Crooks
In this paper, we report the electrosynthesis and characterization of individual, shape-controlled Pt nanocrystals (NCs) electrodeposited on carbon nanoelectrodes (CNEs). Single Pt NCs were deposited onto the CNEs using an empirically developed square-wave potential program. Characterization by scanning electron microscopy indicates that the sizes of Pt NCs are remarkably reproducible (relative standard deviation = 6%). Electrochemically active surface areas, determined by Cu underpotential deposition and H adsorption/desorption analyses, are also reproducible...
July 10, 2018: Faraday Discussions
Mélida Del Pilar Anzola Rojas, Marcelo Zaiat, Ernesto Rafael Gonzalez, Heleen De Wever, Deepak Pant
Microbial electrosynthesis (MES) technology relies on the direct use of electrons to convert CO2 into long chain organic chemicals. Therefore, MES has been proposed to be coupled to the renewable electricity supply, mainly from solar and wind sources. However, those energies suffer fluctuations and interruptions of variable duration, which can have an adverse effect on MES performance. Such effects on MES has been evaluated for the first time under different interruptions time. H-cell-MES reactors were disconnected from power supply during 4, 6, 8, 16, 32 and 64 h...
October 2018: Bioresource Technology
Maria Elvira Carbone, Rosanna Ciriello, Pasquale Moscarelli, Federica Boraldi, Giuliana Bianco, Antonio Guerrieri, Brigida Bochicchio, Antonietta Pepe, Daniela Quaglino, Anna Maria Salvi
This investigation was undertaken to explore the mutual recognition of the pentapeptide (ValGlyGlyValGly)n , a hydrophobic elastin-like peptide (ELP), suspended in deionized water in monomer (n = 1) and trimer (n = 3) forms and the outer surface of a very thin, insulating polymer, poly(ortho-aminophenol) (PoAP), electrochemically grown on a platinum foil by cyclic voltammetry in a neutral medium (phosphate-buffered saline, I = 0.1M) immersed in the suspension. As a prior task, the proved propensity of the ValGlyGlyValGly sequence, at the given minimal length (three or more repeats), to self-assemble into amyloid-like fibrils when solubilized in an aqueous environment was considered within the framework of testing PoAP surfaces for the specific detection of amyloid precursors...
August 2018: Analytical and Bioanalytical Chemistry
Sven D Waniek, Jan Klett, Christoph Förster, Katja Heinze
A series of four ferrocenyl ester compounds, 1-methoxycarbonyl- ( 1 ), 1,1'-bis(methoxycarbonyl)- ( 2 ), 1,1',3-tris(methoxycarbonyl)- ( 3 ) and 1,1',3,3'-tetrakis(methoxycarbonyl)ferrocene ( 4 ), has been studied with respect to their potential use as redox mediators. The impact of the number and position of ester groups present in 1 - 4 on the electrochemical potential E 1/2 is correlated with the sum of Hammett constants. The 1 / 1 + - 4 / 4 + redox couples are chemically stable under the conditions of electrolysis as demonstrated by IR and UV-vis spectroelectrochemical methods...
2018: Beilstein Journal of Organic Chemistry
Marcel Schreier, Youngmin Yoon, Megan N Jackson, Yogesh Surendranath
The dynamics of carbon monoxide on Cu surfaces was investigated during CO reduction, providing insight into the mechanism leading to the formation of hydrogen, methane, and ethylene, the three key products in the electrochemical reduction of CO2 . Reaction order experiments were conducted at low temperature in an ethanol medium affording high solubility and surface-affinity for carbon monoxide. Surprisingly, the methane production rate is suppressed by increasing the pressure of CO, whereas ethylene production remains largely unaffected...
June 19, 2018: Angewandte Chemie
Zhenhua Yan, Hongming Sun, Xiang Chen, Huanhuan Liu, Yaran Zhao, Haixia Li, Wei Xie, Fangyi Cheng, Jun Chen
Electrochemical deposition is a facile strategy to prepare functional materials but suffers from limitation in thin films and uncontrollable interface engineering. Here we report a universal electrosynthesis of metal hydroxides/oxides on varied substrates via reduction of oxyacid anions. On graphitic substrates, we find that the insertion of nitrate ion in graphene layers significantly enhances the electrodeposit-support interface, resulting in high mass loading and super hydrophilic/aerophobic properties. For the electrocatalytic oxygen evolution reaction, the nanocrystalline cerium dioxide and amorphous nickel hydroxide co-electrodeposited on graphite exhibits low overpotential (177 mV@10 mA cm-2 ) and sustains long-term durability (over 300 h) at a large current density of 1000 mA cm-2 ...
June 18, 2018: Nature Communications
Markus D Kärkäs
Conventional methods for carrying out carbon-hydrogen functionalization and carbon-nitrogen bond formation are typically conducted at elevated temperatures, and rely on expensive catalysts as well as the use of stoichiometric, and perhaps toxic, oxidants. In this regard, electrochemical synthesis has recently been recognized as a sustainable and scalable strategy for the construction of challenging carbon-carbon and carbon-heteroatom bonds. Here, electrosynthesis has proven to be an environmentally benign, highly effective and versatile platform for achieving a wide range of nonclassical bond disconnections via generation of radical intermediates under mild reaction conditions...
July 30, 2018: Chemical Society Reviews
Xiaohu Li, Irini Angelidaki, Yifeng Zhang
Biological conversion of CO2 to value-added chemicals and biofuels has emerged as an attractive strategy to address the energy and environmental concerns caused by the over-reliance on fossil fuels. In this study, an innovative microbial reverse-electrodialysis electrolysis cell (MREC), which combines the strengths of reverse electrodialysis (RED) and microbial electrosynthesis technology platforms, was developed to achieve efficient CO2 -to-value chemicals bioconversion by using the salinity gradient energy as driven energy sources...
October 1, 2018: Water Research
Jose A Cornejo, Hua Sheng, Eran Edri, Caroline M Ajo-Franklin, Heinz Frei
By electrochemically coupling microbial and abiotic catalysts, bioelectrochemical systems such as microbial electrolysis cells and microbial electrosynthesis systems synthesize energy-rich chemicals from energy-poor precursors with unmatched efficiency. However, to circumvent chemical incompatibilities between the microbial cells and inorganic materials that result in toxicity, corrosion, fouling, and efficiency-degrading cross-reactions between oxidation and reduction environments, bioelectrochemical systems physically separate the microbial and inorganic catalysts by macroscopic distances, thus introducing ohmic losses, rendering these systems impractical at scale...
June 11, 2018: Nature Communications
Achille De Battisti, Paolo Formaglio, Sergio Ferro, Mustafa Al Aukidy, Paola Verlicchi
Lab-scale experiments using real groundwater were carried out using the CabECO® reactor system in order to evaluate its suitability for producing safe water, acceptable for civil purposes. Trials were carried out in discontinuous and in continuous mode, analyzing the influence of electrical and hydraulic process parameters on the quality of treated water. The use of highly boron-doped diamond electrodes in the reactor allowed the electrosynthesis of considerable amounts of ozone. Because of the relatively high amount of chloride in the groundwater samples, a mixture of HOCl/ClO- was also synthesized...
September 2018: Chemosphere
Maria de Fátima Alves, Ricardo Augusto Moreira de Souza Corrêa, Filipe Soares da Cruz, Diego Leoni Franco, Lucas Franco Ferreira
This paper reports the electrosynthesis and characterisation of a polymeric film derived from 2-hydroxybenzamide over a graphite electrode and its application as an enzymatic biosensor for the determination and quantification of the pesticide fenitrothion. The material was analysed by scanning electron microscopy and its electrochemical properties characterised by cyclic voltammetry and electrochemical impedance spectroscopy. The enzyme tyrosinase was immobilised over the modified electrode by the drop and dry technique...
July 15, 2018: Analytical Biochemistry
Jun Wang, Liang Yu, Lin Hu, Gang Chen, Hongliang Xin, Xiaofeng Feng
Electrochemical reduction of N2 to NH3 provides an alternative to the Haber-Bosch process for sustainable, distributed production of NH3 when powered by renewable electricity. However, the development of such process has been impeded by the lack of efficient electrocatalysts for N2 reduction. Here we report efficient electroreduction of N2 to NH3 on palladium nanoparticles in phosphate buffer solution under ambient conditions, which exhibits high activity and selectivity with an NH3 yield rate of ~4.5 μg mg-1 Pd h-1 and a Faradaic efficiency of 8...
May 15, 2018: Nature Communications
Yuvraj Y Birdja, Rafaël E Vos, Tim A Wezendonk, Lin Jiang, Freek Kapteijn, Marc T M Koper
Heterogenization of molecular catalysts for CO2 electroreduction has attracted significant research activity, due to the combined advantages of homogeneous and heterogeneous catalysts. In this work, we demonstrate the strong influence of the nature of the substrate on the selectivity and reactivity of electrocatalytic CO2 reduction, as well as on the stability of the studied immobilized indium(III) protoporphyrin IX, for electrosynthesis of formic acid. Additionally, we investigate strategies to improve the CO2 reduction by tuning the chemical functionality of the substrate surface by means of electrochemical and plasma treatment and by catalyst encapsulation in polymer membranes...
May 4, 2018: ACS Catalysis
Zehra Zaybak, Bruce E Logan, John M Pisciotta
Electroautotrophic microorganisms accept electrons from a cathode as source of reducing equivalents to drive CO2 fixation by poorly understood mechanisms. Acetogenic bacteria were the first group found to possess the capability for electroautotrophic metabolism in pure culture with associated electrosynthesis of acetate as primary metabolite. Identification of additional electrotrophic species can contribute to our understanding of this unusual form of metabolism. Here, bioelectrochemical techniques, chemical analysis and microscopy were used to determine electrotrophic metabolism of Desulfobacterium autotrophicum HRM2...
October 2018: Bioelectrochemistry
Mickaël Mateos, Rita Meunier-Prest, Olivier Heintz, Frederic Herbst, Jean-Moïse Suisse, Marcel Bouvet
In this work, we report for the first time on a comprehensive study of poly(2,3,5,6-tetrafluoroaniline) (PTFANI). Contrary to the nonfluorinated polyaniline (PANI) or its analogues bearing one fluorine atom, PTFANI is a poorly conductive material. We present a comprehensive study of the electrosynthesized PTFANI from its monomer in an acidic aqueous medium. PTFANI was fully characterized by a potential-pH diagram, spectroelectrochemistry, and electrochemical quartz crystal microbalance (EQCM) measurements, as well as by a morphological study...
June 13, 2018: ACS Applied Materials & Interfaces
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