General Synthesis Research Articles

"Hard" Emulsion-Induced Interface Super-Assembly: A General Strategy for Two-Dimensional Hierarchically Porous Metal-Organic Framework Nanoarchitectures.

Two-dimensional (2D) hierarchically porous metal-organic framework (MOF) nanoarchitectures with tailorable meso-/macropores hold great promise for enhancing mass transfer kinetics, augmenting accessible active sites, and thereby boosting performance in heterogeneous catalysis. However, achieving the general synthesis of 2D free-standing MOF nanosheets with controllable hierarchical porosity and thickness remains a challenging task. Herein, we present an ingenious "hard" emulsion-induced interface super-assembly strategy for preparing 2D hierarchically porous UiO-66-NH2 nanosheets with highly accessible pore channels, tunable meso-/macropore sizes, and adjustable thicknesses. The methodology relies on transforming the geometric shape of oil droplet templates within appropriate oil-in-water emulsions from conventional zero-dimensional (0D) "soft" liquid spheres to 2D "hard" solid sheets below the oil's melting/freezing point. Subsequent surfactant exchange on the surface of 2D "hard" emulsions facilitates the heterogeneous nucleation and interfacial super-assembly of in situ formed mesostructured MOF nanocomposites, serving as structural units, in a loosely packed manner to produce 2D MOF nanosheets with multimodal micro/meso-/macroporous systems. Importantly, this strategy can be extended to prepare other 2D hierarchically porous MOF nanosheets by altering metal-oxo clusters and organic ligands. Benefiting from fast mass transfer and highly accessible Lewis acidic sites, the resultant 2D hierarchically porous UiO-66-NH2 nanosheets deliver a fabulous catalytic yield of approximately 96% on the CO2 cycloaddition of glycidyl-2-methylphenyl ether, far exceeding the yield of approximately 29% achieved using conventional UiO-66-NH2 microporous crystals. This "hard" emulsion-induced interface super-assembly strategy paves a new path toward the rational construction of elaborate 2D nanoarchitecture of hierarchical MOFs with tailored physicochemical properties for diverse potential applications.

PMSGAN: Parallel Multistage GANs for Face Image Translation.

In this article, we address the face image translation task, which aims to translate a face image of a source domain to a target domain. Although significant progress has been made by recent studies, face image translation is still a challenging task because it has more strict requirements for texture details: even a few artifacts will greatly affect the impression of generated face images. Targeting to synthesize high-quality face images with admirable visual appearance, we revisit the coarse-to-fine strategy and propose a novel p arallel m ultistage architecture on the basis of g enerative a dversarial n etworks (PMSGAN). More specifically, PMSGAN progressively learns the translation function by disintegrating the general synthesis process into multiple parallel stages that take images with gradually decreasing spatial resolution as inputs. To prompt the information exchange between various stages, a cross-stage atrous spatial pyramid (CSASP) structure is specially designed to receive and fuse the contextual information from other stages. At the end of the parallel model, we introduce a novel attention-based module that leverages multistage decoded outputs as in situ supervised attention to refine the final activations and yield the target image. Extensive experiments on several face image translation benchmarks show that PMSGAN performs considerably better than state-of-the-art approaches.

Unsupervised Machine Learning Control Techniques for Solving the General Synthesis of Control System Problem

Unsupervised Machine Learning Control Techniques for Solving the General Synthesis of Control System Problem

Suppression of eEF2 phosphorylation alleviates synaptic failure and cognitive deficits in mouse models of Down syndrome.

Cognitive impairment is a core feature of Down syndrome (DS), and the underlying neurobiological mechanisms remain unclear. Translation dysregulation is linked to multiple neurological disorders characterized by cognitive impairments. Phosphorylation of the translational factor eukaryotic elongation factor 2 (eEF2) by its kinase eEF2K results in inhibition of general protein synthesis. We used genetic and pharmacological methods to suppress eEF2K in two lines of DS mouse models. We further applied multiple approaches to evaluate the effects of eEF2K inhibition on DS pathophysiology. We found that eEF2K signaling was overactive in the brain of patients with DS and DS mouse models. Inhibition of eEF2 phosphorylation through suppression of eEF2K in DS model mice improved multiple aspects of DS-associated pathophysiology including de novo protein synthesis deficiency, synaptic morphological defects, long-term synaptic plasticity failure, and cognitive impairments. Our data suggested that eEF2K signaling dysregulation mediates DS-associated synaptic and cognitive impairments. Phosphorylation of the translational factor eukaryotic elongation factor 2 (eEF2) is increased in the Down syndrome (DS) brain. Suppression of the eEF2 kinase (eEF2K) alleviates cognitive deficits in DS models. Suppression of eEF2K improves synaptic dysregulation in DS models. Cognitive and synaptic impairments in DS models are rescued by eEF2K inhibitors.

Stöber method to amorphous metal-organic frameworks and coordination polymers

The Stöber method is a widely-used sol-gel route for synthesizing amorphous SiO2 colloids and conformal coatings. However, the material systems compatible with this method are still limited. Herein, we have extended the approach to metal-organic frameworks (MOFs) and coordination polymers (CPs) by mimicking the Stöber method. We introduce a general synthesis route to amorphous MOFs or CPs by making use of a base-vapor diffusion method, which allows to precisely control the growth kinetics. Twenty-four different amorphous CPs colloids were successfully synthesized by selecting 12 metal ions and 17 organic ligands. Moreover, by introducing functional nanoparticles (NPs), a conformal amorphous MOFs coating with controllable thickness can be grown on NPs to form core-shell colloids. The versatility of this amorphous coating technology was demonstrated by synthesizing over 100 core-shell composites from 20 amorphous CPs shells and over 30 different NPs. Besides, various multifunctional nanostructures, such as conformal yolk-amorphous MOF shell, core@metal oxides, and core@carbon, can be obtained through one-step transformation of the core@amorphous MOFs. This work significantly enriches the Stöber method and introduces a platform, enabling the systematic design of colloids exhibiting different level of functionality and complexity.

Automation in Healthcare: Advantages, Prospects, Perceptual Barriers

Introduction. In healthcare, automation refers to the use of technology to replace manual labor with mechanized processes. It offers solutions to some of the biggest challenges in this field by increasing work efficiency and improving the quality of medical care. The aim of the study was to explore the potential impact of automation on healthcare practices and to investigate the perceptions of healthcare professionals towards these innovations. Materials and methods. The study utilized general scientific research methodologies, including analysis and synthesis. Through the examination of secondary data,, the findings of a sociological survey conducted by Google Cloud commissioned by Harris Poll were analyzed and presented in the context of the studied topic. The questionnaire was filled in by 300 doctors across the United States. Results. Over the next years, global automation in healthcare is expected to see a significant growth due to various growth factors including the continuous improvement of healthcare automation technologies, growing public investment, as well as recognition of the benefits of automation in medical logistics processes, laboratory research and other types of medical and related activities. Automation, such as information technology and control systems, reduces individual efforts in multiple procedures.

Modifications in the T arm of tRNA globally determine tRNA maturation, function, and cellular fitness

Almost all elongator tRNAs (Transfer RNAs) harbor 5-methyluridine 54 and pseudouridine 55 in the T arm, generated by the enzymes TrmA and TruB, respectively, in Escherichia coli. TrmA and TruB both act as tRNA chaperones, and strains lacking trmA or truB are outcompeted by wild type. Here, we investigate how TrmA and TruB contribute to cellular fitness. Deletion of trmA and truB in E. coli causes a global decrease in aminoacylation and alters other tRNA modifications such as acp3U47. While overall protein synthesis is not affected in ΔtrmA and ΔtruB strains, the translation of a subset of codons is significantly impaired. As a consequence, we observe translationally reduced expression of many specific proteins, that are either encoded with a high frequency of these codons or that are large proteins. The resulting proteome changes are not related to a specific growth phenotype, but overall cellular fitness is impaired upon deleting trmA and truB in accordance with a general protein synthesis impact. In conclusion, we demonstrate that universal modifications of the tRNA T arm are critical for global tRNA function by enhancing tRNA maturation, tRNA aminoacylation, and translation, thereby improving cellular fitness irrespective of the growth conditions which explains the conservation of trmA and truB.

β‐Phenethylamine Synthesis: N‐Pyridinium Aziridines as Latent Dual Electrophiles

Abstractβ‐Phenethylamines are widely represented in biologically and pharmacologically active organic small molecules. Here, we introduce N‐pyridinium aziridines as latent dual electrophiles for the synthesis of β‐phenethylamines. Bromide‐promoted ring opening generates β‐halopyridinium amines. Selective Ni‐catalyzed C−C cross‐coupling between organozinc nucleophiles and the benzylic C−Br electrophile affords a diverse family of β‐functionalized phenethylaminopyridinium salts, and coupling is stereoconvergent in the presence of chiral ligands. Subsequent Ni‐catalyzed reductive N−N bond activation within the β‐functionalized phenethylaminopyridinium salts furnishes the products of formal olefin carboamination. Other reductive N−N cleavage reactions are demonstrated to provide access to free primary amines, alkylated amines, heterocycles, and products derived from N‐centered radical chemistry. The developed reaction sequence can be implemented in the context of complex molecules and natural product derivatives. Together, the described results provide a general and modular synthesis of β‐phenethylamines and significantly expand the utility of N‐pyridinium aziridines as linchpins in chemical synthesis.

β-Phenethylamine Synthesis: N-Pyridinium Aziridines as Latent Dual Electrophiles.

β-Phenethylamines are widely represented in biologically and pharmacologically active organic small molecules. Here, we introduce N-pyridinium aziridines as latent dual electrophiles for the synthesis of β-phenethylamines. Bromide-promoted ring opening generates β-halopyridinium amines. Selective Ni-catalyzed C-C cross-coupling between organozinc nucleophiles and the benzylic C-Br electrophile affords a diverse family of β-functionalized phenethylaminopyridinium salts, and coupling is stereoconvergent in the presence of chiral ligands. Subsequent Ni-catalyzed reductive N-N bond activation within the β-functionalized phenethylaminopyridinium salts furnishes the products of formal olefin carboamination. Other reductive N-N cleavage reactions are demonstrated to provide access to free primary amines, alkylated amines, heterocycles, and products derived from N-centered radical chemistry. The developed reaction sequence can be implemented in the context of complex molecules and natural product derivatives. Together, the described results provide a general and modular synthesis of β-phenethylamines and significantly expand the utility of N-pyridinium aziridines as linchpins in chemical synthesis.

Multiaction Pt(IV) Prodrugs Releasing Cisplatin and Dasatinib Are Potent Anticancer and Anti-Invasive Agents Displaying Synergism between the Two Drugs.

Herein, we describe the general design, synthesis, characterization, and biological activity of new multitargeting Pt(IV) prodrugs that combine antitumor cisplatin and dasatinib, a potent inhibitor of Src kinase. These prodrugs exhibit impressive antiproliferative and anti-invasive activities in tumor cell lines in both two-dimensional (2D) monolayers of cell cultures and three-dimensional (3D) spheroids. We show that the cisplatin moiety and dasatinib in the investigated Pt(IV) complexes are both involved in the mechanism of action in MCF7 breast cancer cells and act synergistically. Thus, combining dasatinib and cisplatin into one molecule, compared to using individual components in a mix, may bring several advantages, such as significantly higher activity in cancer cell lines and higher selectivity for tumor cells. Most importantly, Pt(IV)-dasatinib complexes hold significant promise for potential anticancer therapies by targeting epithelial-mesenchymal transition, thus preventing the spread and metastasis of tumors, a value unachievable by a simple combination of both individual components.

Silylene mit kleinen Chalcogenolato‐Substituenten: Variation der Grenzorbitalenergien von O bis Te

AbstractDie Synthesen der heteroleptischen, acyclischen Silylene [(dtbpCbz)SiE16R], die neben dem sterisch anspruchsvollen Carbazolyl‐Liganden dtbpCbz einen Chalcogenolato‐Substituenten der Art E16R=OtBu, SEt, SePh oder TePh tragen, werden detailliert beschrieben. Dabei ist es möglich, Chalcogenolato‐Einheiten einzusetzen, die nur einen geringen sterischen Anspruch aufweisen sowie durch die Wahl des Chalcogenolato‐Substituenten die elektronischen Eigenschaften der Silylene zu variieren. Die daraus resultierenden Effekte werden in den NMR‐ und UV/Vis‐Spektren deutlich. Erste Reaktivitätsstudien der schweren Chalcogenolatosilylene wurden durch Umsetzung mit Trimethylphosphanselenid bzw. mit einem Terphenylazid TerN3, (Ter=2,6‐Dimesitylphenyl) durchgeführt.

Silylenes with a Small Chalcogenide Substituent: Tuning Frontier Orbital Energies from O to Te.

The general synthesis of heteroleptic acyclic silylenes with a bulky carbazolyl substituent (dtbpCbz) is detailed and a series of compounds with a chalcogenide substituent of the type [(dtbpCbz)SiE16R] (E16R=OtBu, SEt, SePh, TePh) is reported. With the bulky carbazolyl substituent present, the chalcogenide moiety can be very small, as is shown by incorporating groups as small as ethyl, phenyl or tert-butyl. For the first time, the electronic properties of the silylene can be tuned along a complete series of chalcogenide substituents. The effects are clearly visible in the NMR and UV/Vis spectra, and were rationalised by DFT computations. The reactivity of the heaviest chalcogenide-substituted silylenes was probed by reactions with trimethylphosphine selenide and the terphenyl azide TerN3 (Ter=2,6-dimesitylphenyl).

General Matrix Synthesis for Cascaded-Block Filters With Flexible Bandwidth

General Matrix Synthesis for Cascaded-Block Filters With Flexible Bandwidth

Construction of an Axial Charge Transfer Channel Between Single-Atom Fe Sites and Nitrogen-Doped Carbon Supports for Boosting Oxygen Reduction.

The introduction of axial-coordinated heteroatoms in Fe─N─C single-atom catalysts enables the significant enhancement of their oxygen reduction reaction (ORR) performance. However, the interaction relationship between the axial-coordinated heteroatoms and their carbon supports is still unclear. In this work, a gas phase surface treatment method is proposed to prepare a series of X─Fe─N─C (X = O, P, and S) single-atom catalysts with axial X-coordination on graphitic-N-rich carbon supports. Synchrotron-based X-ray absorption near-edge structure spectra and X-ray photoelectron spectroscopy indicate the formation of an axial charge transfer channel between the graphitic-N-rich carbon supports and single-atom Fe sites by axial O atoms in O─Fe─N─C. As a result, the O─Fe─N─C exhibits excellent ORR performance with a half-wave potential of 0.905V versus RHE and a high specific capacity of 884 mAh g-1 for zinc-air battery, which is superior to other X─Fe─N─C catalysts without axial charge transfer and the commercial Pt/C catalyst. This work not only demonstrates a general synthesis strategy for the preparation of single-atom catalysts with axial-coordinated heteroatoms, but also presents insights into the interaction between single-atom active sites and doped carbon supports.

General and Scalable Synthesis of 2-Aryl and 2-Alkyl Pyrimidines via an Electronically Tuned SNAr Approach.

An efficient SNAr approach for generating a wide array of 2-aryl and 2-alkyl pyrimidines in good to high yields was developed. This methodology does not require precious metal catalysts and is compatible with aryl, heteroaryl, and alkyl magnesium halides as nucleophiles. This process is scalable and performed at room temperature well below the temperature of the competing decomposition of the activated 2-tert-butyl sulfonyl pyrimidine electrophile.

Controlled Synthesis of Unconventional Phase Alloy Nanobranches for Highly Selective Electrocatalytic Nitrite Reduction to Ammonia.

The controlled synthesis of metal nanomaterials with unconventional phases is of significant importance to develop high-performance catalysts for various applications. However, it remains challenging to modulate the atomic arrangements of metal nanomaterials, especially the alloy nanostructures that involve different metals with distinct redox potentials. Here we report the general one-pot synthesis of IrNi, IrRhNi and IrFeNi alloy nanobranches with unconventional hexagonal close-packed (hcp) phase. Notably, the as-synthesized hcp IrNi nanobranches demonstrate excellent catalytic performance towards electrochemical nitrite reduction reaction (NO2RR), with superior NH3 Faradaic efficiency and yield rate of 98.2 % and 34.6 mg h-1 mgcat -1 (75.5 mg h-1 mgIr -1) at 0 and -0.1 V (vs reversible hydrogen electrode), respectively. Ex/in situ characterizations and theoretical calculations reveal that the Ir-Ni interactions within hcp IrNi alloy improve electron transfer to benefit both nitrite activation and active hydrogen generation, leading to a stronger reaction trend of NO2RR by greatly reducing energy barriers of rate-determining step.

General synthesis of ionic-electronic coupled two-dimensional materials.

Two-dimensional (2D) AMX2 compounds are a family of mixed ionic and electronic conductors (where A is a monovalent metal ion, M is a trivalent metal, and X is a chalcogen) that offer a fascinating platform to explore intrinsic coupled ionic-electronic properties. However, the synthesis of 2D AMX2 compounds remains challenging due to their multielement characteristics and various by-products. Here, we report a separated-precursor-supply chemical vapor deposition strategy to manipulate the chemical reactions and evaporation of precursors, facilitating the successful fabrication of 20 types of 2D AMX2 flakes. Notably, a 10.4 nm-thick AgCrS2 flake shows superionic behavior at room temperature, with an ionic conductivity of 192.8 mS/cm. Room temperature ferroelectricity and reconfigurable positive/negative photovoltaic currents have been observed in CuScS2 flakes. This study not only provides an effective approach for the synthesis of multielement 2D materials with unique properties, but also lays the foundation for the exploration of 2D AMX2 compounds in electronic, optoelectronic, and neuromorphic devices.

General Synthesis of Metal Indium Sulfide Atomic Layers for Photocatalysis.

The metal indium sulfides have attracted extensive research interest in photocatalysis due to regulable atomic configuration and excellent optoelectronic properties. However, the synthesis of metal indium sulfide atomic layers is still challenging since intrinsic non-van-der-Waals layered structures of some components. Here, a surfactant self-assembly growth mechanism is proposed to controllably synthesize metal indium sulfide atomic layers. Eleven types of atomic layers with tunable compositions, thickness, and defect concentrations are successfully achieved namely In2S3, MgIn2S4, CaIn2S4, MnIn2S4, FeIn2S4, ZnIn2S4, Zn2In2S5, Zn4In16S33, CuInS2, CuIn5S8, and CdIn2S4. The typical CaIn2S4 shows a defect-dependence activity for CO2 photoreduction. The designed S vacancies in CaIn2S4 can serve as catalytic centers to activate CO2 molecules via localized electrons for π-back-donation. The engineered S vacancies tune the non-covalent interaction with CO2 and intermediates, manages to tune the free energy, and lower the reaction energy barrier. As a result, the defect-rich CaIn2S4 displays 2.82× improved reduction rate than defect-poor CaIn2S4. Meantime, other components also display promising photocatalytic performance, such as Zn2In2S5 with a H2O2 photosynthesis rate of 292µmolg-1h-1 and CuInS2 with N2-NH4 + conversion rate of 54µmolg-1h-1. This work paves the way for the multidisciplinary exploration of metal indium sulfide atomic layers with unique photocatalysis properties.

General and Facile Synthesis of Co/CoO Nanoparticals Supported by Nitrogen-Doped Graphenic Networks as Efficient Oxygen Electrocatalyst for Zn-Air Batteries.

Reasonable design of low-cost, high-efficiency and stable bifunctional oxygen electrocatalysts is of great significance to improve the reaction efficiency of Zn-air batteries, which is still a huge challenge. Here, we report a highly efficient bifunctional oxygen electrocatalyst with three-dimensional (3D) N-doped graphene network-supported cobalt and cobalt oxide nanoparticles (Co/CoO-NG), which can be in situ synthesized by inducing metal ions on metal plates via graphene oxide as an inducer. This 3D network structure and open active center show excellent bifunctional oxygen electrocatalytic activity under alkaline conditions, and can be used as an air electrode in rechargeable Zn-air batteries, with significantly better power density (244.28 mW cm-2) and stability (over 340 h) than commercial Pt/C+RuO2 mixtures. This work is conducive to advancing the practical application of graphene-based materials as air electrodes for rechargeable zinc-air batteries.

Experimental screening of intermetallic alloys for electrochemical CO2 reduction

In this study, we experimentally screen a promising class of intermetallic alloys for the electrochemical reduction of CO2 toward hydrocarbon products. Based on previous DFT-based screening papers, combinations of strongly CO-binding metals such as iron, cobalt, and nickel with weakly CO-binding metals such as gallium, aluminium or zinc were selected as potentially promising catalytic materials. Despite the challenging production of these alloys, we report a general two-step synthesis method for intermetallic alloys and discuss the specific synthesis conditions that must be taken into account when synthesising these materials. After their synthesis, we use a recently developed differential electrochemical mass spectrometry (DEMS) setup to rapidly quantify the CO2 reduction products over a range of potentials. Almost all newly developed intermetallic catalysts are shown to produce methane and ethylene, while the CoSn catalyst showed higher selectivity towards formate production. However, all tested catalysts mostly produced hydrogen and only reduce CO2 to a small extent, despite the favourable computational screening results. We discuss possible reasons for this discrepancy and outline a more holistic approach for linking future DFT studies with experiments.