890 results match your criteria: "Center for Catalysis[Affiliation]"

In this report, we successfully engineered a novel probe based on an acceptor-donor-acceptor (A-D-A) architecture featuring dicyanovinyl-substituted thieno[3,2-]thiophene, termed DCVTT. The designed probe self-assembles into luminous nanoparticles (DCVTT NPs) upon introducing mixed aqueous solutions. These fluorescent nanostructures served as a ratiometric probe for detecting cyanide (CN) ions in aqueous-based environments, owing to the robust Intramolecular Charge Transfer (ICT) characteristics of DCVTT.

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Cellular activity is spatially organized across different organelles. While several structures are well-characterized, many organelles have unknown roles. Profiling biomolecular composition is key to understanding function but is difficult to achieve in the context of small, dynamic structures.

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Ultrasonic treatment-assisted reductive deposition of Cu and Pd nanoparticles on ultrathin 2D BiS nanosheets for selective electrochemical reduction of CO into C compounds.

Ultrason Sonochem

December 2024

Department of Chemistry, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates 127788; Center for Catalysis and Separations, Khalifa University of Science and Technology, Abu Dhabi, P.O. Box 127788, United Arab Emirates. Electronic address:

In this work, we have ultrasonically deposited Cu and Pd nanoparticles on BiS nanoparticles, prepared using an ultrasonication assisted hydrothermal method. We implemented intense ultrasonic waves bearing frequency of 20 kHz and power of 750 W at the acoustic wavelength of 100 mm to reduce Cu and Pd nanoparticles on the BiS surface. The XRD confirmed the formation of highly crystalline BiS nanoparticles with a pure orthorhombic phase and the deposition of copper (Cu) and palladium (Pd) nanoparticles was indicated by the strengthening and broadening of the peaks.

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Suzuki-Miyaura coupling (SMC), a crucial C-C cross-coupling reaction, is still associated with challenges such as high synthetic costs, intricate work-ups, and contamination with homogeneous metal catalysts. Research intensely focuses on strategies to convert homogeneous soluble metal catalysts into insoluble powder solids, promoting heterogeneous catalysis for easy recovery and reuse as well as for exploring greener reaction protocols. Metal-Organic Frameworks (MOFs), recognized for their high surface area, porosity, and presence of transition metals, are increasingly studied for developing heterogeneous SMC.

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suite of internally functionalized FeL cage complexes has been synthesized with lipophilic end groups to allow dissolution in varied solvent mixtures, and the scope of their molecular recognition of a series of neutral, nonpolar guests has been analyzed. The lipophilic end groups confer cage solubility in solvents with a wide range of polarities, from hexafluoroisopropanol (HFIP) to tetrahydrofuran, and the hosts show micromolar affinities for neutral guests, despite having no flat panels enclosing the cavity. These hosts allow interrogation of the effects of an internal functional group on guest binding properties, as well as solvent-based driving forces for recognition.

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A pair of cyclophane-encapsulated [Cu(μ-E)] complexes (E = S and Se) were characterized by resonant X-ray diffraction anomalous fine structure (DAFS), revealing unexpected polarization among the three Cu sites attributed to long-range effects of π-stacking interactions with cocrystallized benzene molecules. The resonant K-edge energies of individual Cu sites within the cluster molecules were found to vary as a function of distance from the cocrystallized benzene. This pattern was interpreted in the context of T-shaped, edge-to-face π-stacking with the assistance of theoretical charge density difference calculations.

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Selective aqueous anion recognition in an anionic host.

iScience

December 2024

Department of Chemistry and the UCR Center for Catalysis, University of California - Riverside, Riverside, CA 92521, USA.

Article Synopsis
  • * These cages have a negative charge but can still hold onto certain anions that fit in their cavity, while excluding others that are too small or large.
  • * The slow rate of exchanging anions suggests potential for using these cages in environmental applications to manage the release of specific anions over time.
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Ammonia electro-oxidation on nickel hydroxide: phases, pH and poisoning.

Phys Chem Chem Phys

December 2024

Schulich Faculty of Chemistry, The Grand Technion Energy Program, and the Resnick Sustainability Center for Catalysis, Technion - Israel Institute of Technology, Technion City, 3200003 Haifa, Israel.

Nickel hydroxide is a leading alternative to platinum group metals for electrocatalysis of the ammonia oxidation reaction (AOR), an important process for energy conversion and environmental remediation. Nevertheless, the dependence of AOR electrocatalysis on the different crystalline phases at the electrode surface (α-Ni(OH)/γ-NiOOH β-Ni(OH)/β-NiOOH) has never been investigated. Herein, the crystalline β-Ni(OH) and the disordered α-Ni(OH) were synthesized and characterized by XRD, HRSEM, and Raman and FTIR spectroscopies.

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Overuse of levofloxacin (LEV) is often associated with bacterial resistance and serious health problems, underscoring the need for reliable sensing and monitoring of LEV molecules. Therefore, this study aimed to investigate LEV using boron-doped diamond (BDD) and boron-doped diamond modified with MXene (TiCT) (BDD-MXene) electrode. The successful deposition of MXene on the BDD surface was confirmed using scanning electron microscope (SEM).

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Electrochemical immunosensor for the predictive cancer biomarker SLFN11 using reduced graphene oxide/MIL-101(Cr)-NH composite.

Int J Biol Macromol

December 2024

Department of Chemistry, Khalifa University of Science and Technology, Abu Dhabi, P.O. Box 127788, United Arab Emirates; Center for Catalysis and Separations, Khalifa University of Science and Technology, Abu Dhabi, P.O. Box 127788, United Arab Emirates. Electronic address:

SLFN11 is a predictive cancer biomarker essential for identifying tumors that are sensitive to DNA-damaging agents, facilitating more personalized and effective treatment approaches. Detecting this biomarker can guide therapeutic decisions and improve outcomes for cancer patients. However, existing detection methods for SLFN11 are complex and require advanced techniques.

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Gallium-doped zinc oxide (GZO) has demonstrated significant potential in gas-sensing applications due to its enhanced electrical and chemical properties. This study focuses on the synthesis, characterization, and gas-sensing performance of GZO nanoparticles (NPs), specifically targeting CO₂ detection, which is crucial for environmental monitoring and industrial safety. The GZO samples were synthesized using a sol-gel method, and their crystal structure was determined through X-ray diffraction (XRD), confirming the successful incorporation of gallium into the ZnO lattice.

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With growing efforts pushing toward sustainable catalysis, using earth-abundant metals has become increasingly important. Here, we present the first examples of cobalt PCP pincer complexes that demonstrate dual stereoselectivity for allyl ether isomerization. While the cationic cobalt complex [((PCP)Co)-μ-N][BAr ] () mainly favors the -isomer of the enol ether, the corresponding methyl complex [(PCP)CoMe] () mostly gives the -isomer.

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Article Synopsis
  • * The study uses computational methods to investigate how heteroatoms and heterocyclic fusion influence antiaromaticity in -indacene, revealing that both factors significantly impact stability, with the position of substitution being crucial.
  • * The research highlights that while heteroatom effects are stronger, heterocycle fusion still plays a role, and understanding these interactions can help design more stable antiaromatic compounds for electronic applications.
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Quaternary carbon centers are desirable targets for drug discovery and complex molecule synthesis, yet the synthesis of these motifs within traditional cross-coupling paradigms remains a significant challenge due to competing β-hydride elimination pathways. In contrast, the bimolecular homolytic substitution (S2) mechanism offers a unique and attractive alternative pathway. Metal porphyrin complexes have emerged as privileged catalysts owing to their ability to selectively form primary metal-alkyl complexes, thereby eliminating the challenges associated with tertiary alkyl complexation with a metal center.

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Stereoselective Synthesis of 1,n-Dicarbonyl Compounds Through Palladium-Catalyzed Ring Opening/Isomerization of Densely Substituted Cyclopropanols.

Angew Chem Int Ed Engl

November 2024

Schulich Faculty of Chemistry and the, Resnick Sustainability Center for Catalysis, Technion-, Israel Institute of Technology, Haifa, 3200009, Israel.

We report a highly diastereoselective protocol for the synthesis of 1,4- and 1,5-dicarbonyl compounds from densely substituted cyclopropanols. The methodology involves a palladium-catalyzed ring opening reaction followed by a "metal-walk" and oxidation of a remote hydroxyl group. The methodology represents a new application of cyclopropanols as initiation sites for chain walking remote functionalization.

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Phagocytosis is usually carried out by professional phagocytic cells in the context of pathogen response or wound healing. The transient surface proteins that regulate phagocytosis pose a challenging proteomics target; knowledge thereof could lead to new therapeutic insights. Herein, we describe a novel photocatalytic proximity labeling method: "μMap-Interface", allowing for spatiotemporal mapping of phagocytosis.

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Tuning the charge density at the active site to balance the adsorption ability and reactivity of oxygen is extremely significant for driving a two-electron oxygen reduction reaction (ORR) to produce hydrogen peroxide (HO). Herein, we have highlighted the influence of intermolecular polarity in covalent organic frameworks (COFs) on the efficiency and selectivity of electrochemical HO production. Different C3 symmetric building blocks have been utilized to regulate the charge density at the active sites.

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Stereochemical Impacts on Acyclic Mechanochemical Carbon-Carbon Bond Activation.

Angew Chem Int Ed Engl

October 2024

Schulich Faculty of Chemistry and the Resnick Sustainability Center for Catalysis, Technion - Israel Institute of Technology, Haifa, 3200008, Israel.

The influence of stereochemistry on the mechanochemistry rate is studied using a new mechanophore based on a benzopinacol (BP) skeleton. Two sets of BP diastereomers, the meso R,S and the R,R/S,S were isolated, incorporated into the center of a poly(methyl acrylate), and their mechanical activation rate was measured in solution. Under mechanical stress, the central C-C bond in BP is cleaved, providing two independent benzophenone molecules with higher UV-absorption coefficient at 254 nm.

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Artificial Neural Networks are incredibly efficient at handling complicated and nonlinear mathematical problems, making them very useful for tackling these challenges. Artificial neural networks offer a special computational architecture that is extremely valuable in disciplines like biotechnology, biological computing, and computational fluid dynamics. The present work investigates the applicability of back-propagation artificial neural networks in conjunction with the Levenberg-Marquardt algorithm for evaluating heat transmission in hybrid nanofluids.

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Energy harvesting from ambient sources present in the environment is essential to replace traditional energy sources. These strategies can diversify the energy sources, reduce maintenance, lower costs, and provide near-perpetual operation of the devices. In this work, a triboelectric nanogenerator (TENG) based on silane-coupled Linde type A/polydimethylsiloxane (LTA/PDMS) is developed for harsh environmental conditions.

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Isocyanide Substituent Influences Reductive Elimination versus Migratory Insertion in Reaction with an [Fe(μ-H)] Complex.

Inorg Chem

November 2024

Center for Catalysis and Florida Center for Heterocyclic Chemistry, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States.

Iron hydrides are proposed reactive intermediates for N and CO conversion in industrial and biological processes. Here, we report a reactivity study of a low-coordinate di(μ-hydrido)diiron(II) complex, Fe(μ-H), where is a bis(β-diketiminate) cyclophane, with isocyanides, which have electronic structures related to N and CO. The reaction outcome is influenced by the isocyanide substituent, with 2,6-xylyl isocyanide leading to H loss, to form a bis(μ-1,1-isocyanide)diiron(I) complex, whereas all of the other tested isocyanides insert into the Fe-H bond to give (μ-1,2-iminoformyl) complexes.

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Copper-Catalyzed Carbomagnesiation of 1-Halocyclopropenes.

Org Lett

October 2024

Schulich Faculty of Chemistry and the Resnick Sustainability Center for Catalysis, Technion - Israel Institute of Technology, Technion City, 3200009 Haifa, Israel.

We report a versatile copper-catalyzed carbomagnesiation reaction of poly- and fully substituted 1-halocyclopropenyl esters. By fine-tuning the regioselectivity of the addition, we were able to access configurationally stable fully substituted cyclopropyl carbenoid intermediates. These intermediates were subsequently trapped with electrophiles to furnish stereodefined poly- and fully substituted halocyclopropyl esters.

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This study presents a single-site microkinetic model for methanol synthesis by CO hydrogenation over intermetallic PdGa/SiO. A reaction path analysis (RPA) combining theoretical results and realistic catalyst surface reaction data is established to elucidate the reaction mechanism and kinetic models of CO hydrogenation to methanol and CO. The RPA leads to the derivation of rate expressions for both reactions without presumptions about the most abundant reactive intermediate (MARI) and rate-determining step (rds).

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Anion-Exchange Membrane Oxygen Separator.

ACS Org Inorg Au

October 2024

The Wolfson Department of Chemical Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel.

Anion-exchange membranes (AEMs), known for enabling the high conductivity of hydroxide anions through dense polymeric structures, are pivotal components in fuel cells, electrolyzers, and other important electrochemical systems. This paper unveils an unprecedented utilization of AEMs in an electrochemical oxygen separation process, a new technology able to generate enriched oxygen from an O/N mixture using a small voltage input. We demonstrate a first-of-its-kind AEM-based electrochemical device that operates under mild conditions, is free of liquid electrolytes or sweep gases, and produces oxygen of over 96% purity.

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N activation is a vital step in the process toward NH production. NH synthesis has been considered a crucial process for the production of value-added chemicals and/or hydrogen carriers over recent years. In this work, density functional theory (ab initio) calculations are implemented for a thorough screening of bimetallic alloy surfaces using Fe, Ru, and Mo as the matrix (host) metals and Ag, Au, Co, Cu, Fe, Mo, Ni, Pd, Pt, Rh, and Rh as heterometals toward exploring the N catalytic activation (electronic and chemical characteristics); the monometallic surfaces are used for critical comparison in terms of their N activation behavior.

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