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Herein, we report a directing-group-enabled Huisgen cycloaddition of azides and alkynes for the synthesis of functionalized triazoles in which the triazene group could act as a directing group to enable this regioselective [3 + 2] cycloaddition and further replacement by diverse groups, including amino, amide, halogen, and heterocycle substituents. This method represents a general and practical synthesis of triazoles under mild reaction conditions and broad substrate scope.The selective separation of trivalent americium from lanthanides in a nitric acid medium by a tetradentate ligand, N,N'-diethyl-N,N'-ditolyl-2,9-diamide-1,10-phenanthroline (Et-Tol-DAPhen), in an ionic liquid (IL), C4mimNTf2, was studied by batch solvent extraction and spectroscopic approaches. The effect of various parameters such as the contact time, temperature, extractant concentration, and acidity on the extraction of Am3+ and Eu3+ have been evaluated. A significant enhancement in the extraction ability of Et-Tol-DAPhen dissolved in IL was observed as compared to that in molecular diluents under low-acid conditions. The chemical stoichiometry of Am3+ and Eu3+ complexes during extraction was determined to be 12 (metal/ligand) by slope analysis of the extraction data. The extraction mechanism of Am3+ and Eu3+ by Et-Tol-DAPhen in IL was determined to be cation exchange on the basis of the effect of nitrate, NTf2-, and C4mim+ ions on extraction. The coordination chemistry of Ln3+ with the ligand in C4mimNTf2 was studied by spectroscopic titrations, which helped to further identify and confirm the extracted species as well as the extraction mechanism. Results from the present study emphasize the unique role of IL in altering the extraction behavior and suggest that the Et-Tol-DAPhen/IL system has potential applications in trivalent actinide/lanthanide separation under low-acid conditions.Deep eutectic solvents (DESs) are novel environment-friendly media for a variety of applications. In order to obtain insight into the structure and dynamics of some less-explored DESs comprising ethylene glycol and tetraalkylammonium bromide salts with variable alkyl chain length, we have captured complete dynamics occurring in these solvents in a timescale of few femtoseconds to several nanoseconds by monitoring the time-dependent fluorescence Stokes shift of coumarin 153 employing a combination of time-correlated single-photon counting and fluorescence upconversion techniques. The solvent response function constructed from the measured data reveals a sub-picosecond component (∼0.8 ps, 20-35%) in addition to a slow component (180-475 ps) with a distribution of relaxation time. The slow time component is found to be strongly dependent on the viscosity of the medium, indicating that it arises from the diffusive motions of the solvent constituents into and out of the solvation shell, whereas the ultrafast time component, which is nearly independent of the solvent viscosity, arises from fast local motions of the constituents in the immediate vicinity of the solute molecule.Advances made in fabrication of patterned surfaces with well-defined dimensions of topographic features and their lateral dissemination drive the progress in interpretation of liquid spreading, adhesion, and retreat on engineered solid surfaces. Despite extensive studies on liquid droplet spreading and adhesion on textured surfaces in recent years, conformation of the three-phase contact line and its effect on macroscopic contact angle and droplet adhesion remain the focus of intensive debate. Here, we investigate the effect of surface topography on the adhesion force of Cassie-Baxter-state droplets on concentric ring-textured hydrophobic surfaces having rings with lateral dimensions of 5, 10, and 45 μm and separated by 5, 6, and 7 μm trenches, respectively, with fixed depth of 15 μm. Unlike mostly tested surfaces textured with straight ridges, pores, and pillars, where the droplet base contact line is anisotropic and its conformation varies along the apparent boundary, concentric rings are symmetrical and reinforce the microscopic contact line to align to a circular one that reflects the shape of the pattern. In this study, adhesion forces were calculated based on surface tension and Laplace pressure forces and were compared with the experimental forces for both water and ethylene glycol droplets having a varying contact diameter on the concentric ring-pattern at the point of maximum adhesion force. Results show that the microscopic contact line of the liquid retains its circular shape controlled by circular rings of the pattern, irrespectively of the droplet base diameter larger than 0.8 mm, and there is a good agreement between the experimental and calculated adhesion forces.A general and practical method for decarboxylative hydroxylation of carboxylic acids was developed through visible light-induced photocatalysis using molecular oxygen as the green oxidant. The addition of NaBH4 to in situ reduce the unstable peroxyl radical intermediate much broadened the substrate scope. Different sp3 carbon-bearing carboxylic acids were successfully employed as substrates, including phenylacetic acid-type substrates, as well as aliphatic carboxylic acids. This transformation worked smoothly on primary, secondary, and tertiary carboxylic acids.We have investigated the chemical bath deposition (CBD) of CuS using thioacetamide on functionalized self-assembled monolayers (SAMs) using scanning electron and optical microscopies, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry. For all SAMs studied, the amount of CuS deposited is strongly dependent on the bath pH and can be attributed to the interaction of the SAM terminal groups with the chalcogenide ions present in solution. For -CH3-terminated SAMs, there is a steady increase in the amount of CuS deposited with an increase in the bath pH because there is an increase in the concentration of chalcogenide ion. However, for -OH- and -COOH-terminated SAMs, we observe that the maximum amount of CuS is deposited at pH 10. We attribute this behavior to a competition between the repulsion of the chalcogenide ions by the negatively charged SAM terminal groups and an increase in the chalcogenide ion concentration with an increase in the bath pH. Using the interaction of the chalcogenide ions with the different SAM terminal functional groups, we demonstrate that CuS can be selectively deposited on the -CH3-terminated areas of patterned -OH/-CH3- and -COOH/-CH3-terminated SAMs.Algae products are attracting growing interest due to their pleasant taste and their high contents in protein, essential amino acids, vitamins, and minerals. Specifically, spirulina products are widely promoted for their high vitamin B12 content. So far, knowledge regarding the contamination with cyanotoxins, heavy metals, pesticides, or polycyclic aromatic hydrocarbons (PAHs) is scarce, although some studies reported high contaminant levels in spirulina products. The regular intake of spirulina, and very likely other algae products as well, as a dietary supplement in the gram range demands a closer monitoring of potentially harmful constituents.Antioxidant metabolites contribute to alleviating oxidative stress caused by reactive oxygen species (ROS) in microorganisms. We utilized oxidative stressors such as hydrogen peroxide supplementation to increase the yield of the bioactive secondary metabolite antioxidant antrodin C in submerged fermentations of the medicinal mushroom Antrodia cinnamomea. Changes in the superoxide dismutase and catalase activities of the cells indicate that ROS are critical to promote antrodin C biosynthesis, while the ROS production inhibitor diphenyleneiodonium cancels the productivity-enhancing effects of H2O2. Transcriptomic analysis suggests that key enzymes in the mitochondrial electron transport chain are repressed during oxidative stress, leading to ROS accumulation and triggering the biosynthesis of antioxidants such as antrodin C. Accordingly, rotenone, an inhibitor of the electron transport chain complex I, mimics the antrodin C productivity-enhancing effects of H2O2. Delineating the steps connecting oxidative stress with increased antrodin C biosynthesis will facilitate the fine-tuning of strategies for rational fermentation process improvement.Phenoxyalkanoic acid (PAA) herbicides are mainly metabolized by microorganisms in soils, but the degraders that perform well under alkaline environments are rarely considered. Herein, we report Cupriavidus oxalaticus strain X32, which showed encouraging PAA-degradation abilities, PAA tolerance, and alkali tolerance. In liquid media, without the addition of exogenous carbon sources, X32 could completely remove 500 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) or 4-chloro-2-methylphenoxyacetic acid within 3 days, faster than that with the model degrader Cupriavidus necator JMP134. Particularly, X32 still functioned at pH 10.5. Of note, with X32 inoculation, we observed 2,4-D degradation in soils and diminished phytotoxicity to maize (Zea mays). Furthermore, potential mechanisms underlying PAA biodegradation and alkali tolerance were then analyzed by whole-genome sequencing. Three modules of tfd gene clusters involved in 2,4-D catabolism and genes encoding monovalent cation/proton antiporters involved in alkali tolerance were putatively identified. Thus, X32 could be a promising candidate for the bioremediation of PAA-contaminated sites, especially in alkaline surroundings.Hierarchically porous materials with high stability and tailorable pore characters have potential for mass transfer applications, including bulky molecule capture and separation, heterogeneous catalysis, and drug delivery. https://www.selleckchem.com/products/emd638683.html The scope of functionalities can be notably broadened by employing metal-organic framework (MOF) sheets with tunable thickness as giant molecular building blocks for self-assembly into hierarchical supramolecular porous coordination materials. However, synthesizing MOF sheets with controllable bulkiness has proved challenging for scientists. We present a rational yet unprecedented bottom-up strategy to prepare a novel two-dimensional MOF sheet [Zn(BPDI)(Py)2] (BPDI = N,N'-bis(glycinyl)pyromellitic diimide; Py = pyridine) with unusual and highly desired tunable thickness. These sheets self-organize into a unique three-dimensional supramolecular coordination material (NEU-1) with tailorable porosity. To assess its technological relevance, NEU-1c is tested as a support of amine sorbent for CO2 capture. Multichannel porous NEU-1c solves the conventional trade-off suffered by supported amine carbon dioxide adsorbents between increasing amine content and decreasing access to amine sites. Our synthesis process opens the door to novel MOF nanosheets and unique hierarchical supramolecular porous materials with tailorable porosity.The meta-CAr-H bond formylation of arenes has been achieved using CHBr3 as a formyl source in the presence of [Ru(p-cym)(OAc)2] as a catalyst. This method provides efficient access to the preparation of various meta-substituted aromatic compounds, such as alcohols, ethers, amines, nitriles, alkenes, halogens, carboxylic acids, and their derivatives, through transformation of the versatile formyl group. Furthermore, mechanistic studies show that the key active species is a pentagonal ruthenacycle complex.
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