keyword
MENU ▼
Read by QxMD icon Read
search

Organic chemistry*

keyword
https://www.readbyqxmd.com/read/28926233/copper-i-catalyzed-regio-and-stereoselective-intramolecular-alkylboration-of-propargyl-ethers-and-amines
#1
Hiroaki Iwamoto, Yu Ozawa, Koji Kubota, Hajime Ito
The copper(I)-catalyzed regio- and stereoselective intramolecular alkylation of propargyl ethers and amines bearing an alkyl electrophilic moiety has been developed. The reaction showed high functional group tolerance and gave highly functionalized alkenylboronates bearing heterocyclic rings, which are versatile synthetic intermediates in organic chemistry. The borylation products can be transformed into multi-substituted alkenes through stereospecific transformations. Mechanistic studies showed that the chemo- and stereoselectivity of copper(I)-catalyzed borylation depends on the type of leaving group...
September 19, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28925326/a-nitrogen-transformation-model-for-multi-layer-enhanced-groundwater-remediation-technology
#2
Yu Yang, Zhifei Ma, Yonghai Jiang, Xinying Lian, Beidou Xi, Yu Pei
The multi-layer enhanced groundwater remediation technology (MET) is an innovative platform that integrates physical chemistry, bioremediation, and phytoremediation technology to safely and effectively remediate ammonia nitrogen in groundwater. A nitrogen transformation model was established to study the mechanism of nitrogen transformation within ammonia nitrogen removal in the MET. The model considered organic nitrogen, ammonia nitrogen, and nitrate nitrogen as the variables, and ammonification, nitrification, denitrification, microbial assimilation, plant absorption, adsorption-desorption, and volatilization as the influencing factors...
September 19, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28924613/ligand-induced-twisting-of-nanoplatelets-and-their-self-assembly-into-chiral-ribbons
#3
Santanu Jana, Marta de Frutos, Patrick Davidson, Benjamin Abécassis
The emergence of chirality is a central issue in chemistry, materials science, and biology. In nanoparticle assemblies, chirality has been shown to arise through a few different processes, but chiral organizations composed of plate-like nanoparticles, a class of material under scrutiny due to their wide applicative potential, have not yet been reported. We show that ribbons of stacked board-shaped cadmium selenide (CdSe) nanoplatelets (NPLs) twist upon the addition of oleic acid ligand, leading to chiral ribbons that reach several micrometers in length and display a well-defined pitch of ~400 nm...
September 2017: Science Advances
https://www.readbyqxmd.com/read/28923590/isoprostanes-neuroprostanes-and-phytoprostanes-an-overview-of-25years-of-research-in-chemistry-and-biology
#4
REVIEW
Jean-Marie Galano, Yiu Yiu Lee, Camille Oger, Claire Vigor, Joseph Vercauteren, Thierry Durand, Martin Giera, Jetty Chung-Yung Lee
Since the beginning of the 1990's diverse types of metabolites originating from polyunsaturated fatty acids, formed under autooxidative conditions were discovered. Known as prostaglandin isomers (or isoprostanoids) originating from arachidonic acid, neuroprostanes from docosahexaenoic acid, and phytoprostanes from α-linolenic acid proved to be prevalent in biology. The syntheses of these compounds by organic chemists and the development of sophisticated mass spectrometry methods has boosted our understanding of the isoprostanoid biology...
September 15, 2017: Progress in Lipid Research
https://www.readbyqxmd.com/read/28922501/formation-and-structural-diversity-of-organo-functionalized-tin-silver-selenide-clusters
#5
Stefanie Dehnen, Niklas Rinn, Lukas Guggolz, Katharina Gries, Kerstin Volz, Jürgen Senker
When reacting the organic functionalized tin selenide clusters [(SnR1)3Se4Cl] (A, R1 = CMe2CH2C(O)Me) or [(SnR1)4Se6] (B) with (SiMe3)2Se and [Ag(PPh3)3Cl] at -78°C in CH2Cl2, a microcrystalline, intermediate (compound 1) precipitates, which was investigated by magic angle spinning (MAS) NMR spectroscopy, powder X-ray diffraction (PXRD), energy dispersive X-ray (EDX) spectroscopy, and quantum chemistry. From these studies, a suggestion about its identity was derived. Compound 1 re-dissolves under reorganization into the organo-functionalized Ag/Sn/Se cluster compound [Ag6(μ6 Se)(Ag8Se12){(R1Sn)2Se2}6] (2), or the mixed-valence cluster [(AgPPh3)2(SnIICl)2Se2{(R1SnIV)2Se2}2] (3), depending on the presence or the exclusion of daylight, respectively...
September 18, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28922481/photo-induced-assembly-of-a-luminescent-tetraruthenium-square
#6
Baptiste Laramée-Milette, Francesco Nastasi, Fausto Puntoriero, Sebastiano Campagna, Garry S Hanan
Self-assembly is a powerful synthetic tool that has led to the development of one-, two- and three-dimensional architectures. From MOFs to molecular flasks, self-assembled materials have proven to be of great interest to the scientific community. Here we describe a strategy for the construction and de-construction of a supramolecular structure through unprecedented photo-induced assembly and dis-assembly. The combination of two approaches, a [n×1]-directional bonding strategy and a ligand photo-dissociation strategy, allows the photo-induced assembly of a polypyridyl Ru(II) precursor into a discrete molecular square...
September 18, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28921969/flow-electrolysis-cells-for-the-synthetic-organic-chemistry-laboratory
#7
Derek Pletcher, Robert A Green, Richard C D Brown
Electrosynthesis has much to offer to the synthetic organic chemist. But in order to be widely accepted as a routine procedure in an organic synthesis laboratory, electrosynthesis needs to be presented in a much more user-friendly way. The literature is largely based on electrolysis in a glass beaker or H-cells that often give poor performance for synthesis with a very slow rate of conversion and, often, low selectivity and reproducibility. Flow cells can lead to much improved performance. Electrolysis is participating in the trend toward continuous flow synthesis, and this has led to a number of innovations in flow cell design that make possible selective syntheses with high conversion of reactant to product with a single passage of the reactant solution through the cell...
September 18, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28920010/exploring-step-by-step-assembly-of-nanoparticle-cytochrome-biohybrid-photoanodes
#8
Ee Taek Hwang, Katherine L Orchard, Daisuke Hojo, Joseph Beton, Colin W J Lockwood, Tadafumi Adschiri, Julea N Butt, Erwin Reisner, Lars J C Jeuken
Coupling light-harvesting semiconducting nanoparticles (NPs) with redox enzymes has been shown to create artificial photosynthetic systems that hold promise for the synthesis of solar fuels. High quantum yields require efficient electron transfer from the nanoparticle to the redox protein, a property that can be difficult to control. Here, we have compared binding and electron transfer between dye-sensitized TiO2 nanocrystals or CdS quantum dots and two decaheme cytochromes on photoanodes. The effect of NP surface chemistry was assessed by preparing NPs capped with amine or carboxylic acid functionalities...
August 2017: ChemElectroChem
https://www.readbyqxmd.com/read/28918628/breaking-benzene-aromaticity-computational-insights-into-the-mechanism-of-the-tungsten-containing-benzoyl-coa-reductase
#9
Martin Culka, Simona G Huwiler, Matthias Boll, G Matthias Ullmann
Aromatic compounds are environmental pollutants with toxic and carcinogenic properties. Despite the stability of aromatic rings, bacteria are able to degrade the aromatic compounds into simple metabolites and use them as growth substrates under oxic or even under anoxic conditions. In anaerobic microorganisms, most monocyclic aromatic growth substrates are converted to the central intermediate benzoyl-coenzyme A, which is enzymatically reduced to cyclohexa-1,5-dienoyl-CoA. The strcitly anaerobic bacterium \textit{Geobacter metallireducens} uses the class II benzoyl-CoA reductase complex for this reaction...
September 18, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28915454/assessing-the-potential-contributions-of-additional-retention-processes-to-pfas-retardation-in-the-subsurface
#10
Mark L Brusseau
A comprehensive understanding of the transport and fate of per- and poly-fluoroalkyl substances (PFAS) in the subsurface is critical for accurate risk assessments and design of effective remedial actions. A multi-process retention model is proposed to account for potential additional sources of retardation for PFAS transport in source zones. These include partitioning to the soil atmosphere, adsorption at air-water interfaces, partitioning to trapped organic liquids (NAPL), and adsorption at NAPL-water interfaces...
September 12, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28915446/embracing-chemical-and-structural-diversity-with-uconga-a-universal-conformer-generation-and-analysis-program
#11
Nathaniel R Gunby, Sarah L Masters, Deborah L Crittenden
Molecular properties depend on molecular structure, so the first step in any computational chemistry investigation is to generate all thermally accessible conformers. Typically it is necessary to make a trade-off between the number of conformers to be explored and the accuracy of the method used to calculate their energies. Ab initio potential energy surface scans can, in principle, be applied to any molecule, but their conformational cost scales poorly with both molecular size and dimensionality of the search space...
September 6, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28915088/abiotic-and-biotic-formation-of-amino-acids-in-the-enceladus-ocean
#12
Elliot L Steel, Alfonso Davila, Christopher P McKay
The active plume at Enceladus' south pole makes the indirect sampling of its global ocean possible. The partially resolved chemistry of the plume, which points to conditions that are seemingly compatible with life, has made orbital sampling missions a priority. We present a conceptual model of energy flux, hydrothermal H2 production, and both abiotic and biotic production of amino acids. Based on the energy flux observed at the south pole and the inferred internal hydrothermal activity, we estimate an H2 production of 0...
September 2017: Astrobiology
https://www.readbyqxmd.com/read/28914790/ancient-living-organisms-escaping-from-or-imprisoned-in-the-vents
#13
REVIEW
J Baz Jackson
We have recently criticised the natural pH gradient hypothesis which purports to explain how the difference in pH between fluid issuing from ancient alkali vents and the more acidic Hadean ocean could have driven molecular machines that catalyse reactions that are useful in prebiotic and autotrophic chemistry. In this article, we temporarily suspend our earlier criticism while we consider difficulties for primitive organisms to have managed their energy supply and to have left the vents and become free-living...
September 15, 2017: Life
https://www.readbyqxmd.com/read/28914473/ethers-on-si-001-a-prime-example-for-the-common-ground-between-surface-science-and-molecular-organic-chemistry
#14
Lisa Pecher, Slimane Laref, Marc Raupach, Ralf Ewald Tonner
Using computational chemistry, we show that the adsorption of ether molecules on Si(001) under ultra-high vacuum conditions can be understood with textbook organic chemistry. The two-step reaction mechanism of (1) dative bond formation between the ether oxygen and a Lewis acidic surface atom and (2) a nucleophilic attack of a nearby Lewis basic surface atom is analysed in detail and found to mirror the acid-catalysed ether cleavage in solution. The O-Si dative bond is found to be the strongest of its kind and reactivity from this state defies the Bell-Evans-Polanyi principle...
September 15, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28913536/isoreticular-expansion-of-polymofs-achieves-high-surface-area-materials
#15
Giulia E M Schukraft, Sergio Ayala, Benjamin L Dick, Seth M Cohen
The concept of isoreticular chemistry has become a core principle in metal-organic framework (MOF) materials. Isoreticular chemistry has shown that organic ligands of different sizes, but with a common geometry/symmetry can be used to generate MOFs of related topologies, but with expanded pore sizes and volumes. In this report, polymer-MOF hybrid materials (polyMOFs) with a UiO (UiO = University of Oslo) architecture are shown to adhere to the principle of isoreticular expansion, generating polyMOFs with large surface areas and enhanced stability...
September 15, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28913530/why-microfluidics-merits-and-trends-in-chemical-synthesis
#16
REVIEW
Yong Liu, Xingyu Jiang
The intrinsic limitations of conventional batch synthesis have hindered its applications in both solving classical problems and exploiting new frontiers. Microfluidic technology offers a new platform for chemical synthesis toward either molecules or materials, which has promoted the progress of diverse fields such as organic chemistry, materials science, and biomedicine. In this review, we focus on the improved performance of microreactors in handling various situations, and outline the trend of microfluidic synthesis (microsynthesis, μSyn) from simple microreactors to integrated microsystems...
September 15, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28913523/the-difficult-search-for-organocerium-iv-compounds
#17
Reiner Anwander, Michael Dolg, Frank T Edelmann
This Tutorial Review provides an overview of the historic and current development of the organometallic chemistry of cerium in its oxidation state 4+. Among the tetravalent lanthanide ions, only Ce(4+) forms stable coordination compounds (e.g. (NH4)2[Ce(NO3)6]). Important fields of applications for cerium(iv) compounds include organic synthesis, bioinorganic chemistry, materials science, and industrial catalysis. In sharp contrast, organometallic cerium(iv) compounds are still exceedingly rare. The history of organocerium(iv) compounds is an exciting story of ups and downs...
September 15, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/28910746/transport-of-imidazolium-based-ionic-liquids-with-different-anion-cation-species-in-sand-soil-columns
#18
Zhiqiang Dong, Li Wei, Suwei Xu, Jingwei Sun, Xinyi Shi, Yuping Qiu
Ionic liquids (ILs) have been widely used as environmentally friendly solvents to replace volatile organic solvents in the chemistry industries. They have a high water solubility and potential risk to organisms in the soil-water environment. At present, most studies focused on the batch sorption of ILs in soil and neglected the investigation of IL transports in soil, which results in a lack of understanding of the structure-dependent mobility of ILs in the environment. Laboratory-scale sand/soil column experiments were performed to study the transport of imidazolium-based ILs, such as [C4mim][OTF], [C4mim][TOS], [C4mim][MeSO3], [C4mim][BF4], [C2mim][BF4], and [C6mim][BF4] including different counteranions and alkyl chain lengths of IL cations...
September 11, 2017: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/28910143/the-lost-city-hydrothermal-field-a-spectroscopic-and-astrobiological-analogue-for-nili-fossae-mars
#19
Elena S Amador, Joshua L Bandfield, William J Brazelton, Deborah Kelley
Low-temperature serpentinization is a critical process with respect to Earth's habitability and the Solar System. Exothermic serpentinization reactions commonly produce hydrogen as a direct by-product and typically produce short-chained organic compounds indirectly. Here, we present the spectral and mineralogical variability in rocks from the serpentine-driven Lost City Hydrothermal Field on Earth and the olivine-rich region of Nili Fossae on Mars. Near- and thermal-infrared spectral measurements were made from a suite of Lost City rocks at wavelengths similar to those for instruments collecting measurements of the martian surface...
September 14, 2017: Astrobiology
https://www.readbyqxmd.com/read/28906074/fully-automated-quantum-chemistry-based-computation-of-spin-spin-coupled-nuclear-magnetic-resonance-spectra-for-molecules
#20
Stefan Grimme, Christoph Bannwarth, Sebastian Dohm, Andreas Hansen, Jana Pisarek, Philipp Pracht, Jakob Seibert, Frank Neese
We present a composite procedure for the quantum chemical computation of spin-spin coupled 1H-NMR spectra for general, flexible molecules in solution. It is based on four main steps, namely, conformer/rotamer ensemble (CRE) generation by the fast tight-binding method GFN-xTB and a newly developed search algorithm, relative free energy and NMR parameter computation, and solution of the spin-Hamiltonian. In this way the NMR-specific nuclear permutation problem is solved and the correct spin-symmetries are obtained...
September 14, 2017: Angewandte Chemie
keyword
keyword
3485
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"