Direct Synthesis Research Articles

Chemo-, Regio- and Stereoselective Preparation of (Z)-2-Butene-1,4-Diol Monoesters via Pd-Catalyzed Decarboxylative Acyloxylation.

(Z)-alkenes are useful synthons but thermodynamically less stable than their (E)-isomers and typically more difficult to prepare. The synthesis of 1,4-hetero-bifunctionalized (Z)-alkenes is particularly challenging due to the inherent regio- and stereoselectivity issues. Herein we demonstrate a general, chemoselective and direct synthesis of (Z)-2-butene-1,4-diol monoesters. The protocol operates within a Pd-catalyzed decarboxylative acyloxylation regime involving vinyl ethylene carbonates (VECs) and various carboxylic acids as the reaction partners under mild and operationally attractive conditions. The newly developed process allows access to a structurally diverse pool of (Z)-2-butene-1,4-diol monoesters in good yields and with excellent regio- and stereoselectivity. Various synthetic transformations of the obtained (Z)-2-butene-1,4-diol monoesters demonstrate how these synthons are of great use to rapidly diversify the portfolio of these formal desymmetrized (Z)-alkenes.

Multi-aspect assessment of a novel geothermal-driven polygeneration arrangement using water electrolyzer, methanol synthesis unit, and Goswami cycle

Geothermal energy’s renewable nature with minimal emissions compared to fossil fuels has led to valuable polygeneration models in geothermal-rich regions, promoting energy sustainability. Key challenges include improving integrated structures due to these resources’ low/medium temperature nature and assessing the feasibility of producing essential products (e.g., hydrogen and methanol), typically produced in structures with substantial pollution. The proposed system’s innovations focus on reducing irreversibility through thermal integration, introducing a negative CO2 emission structure, and utilizing CO2 hydrogenation based on geothermal energy for methanol production. Hence, the system encompasses a geothermal power plant, a Goswami cycle, a direct hydrogenation methanol synthesis unit, and a proton exchange membrane electrolyzer. The findings show generating methanol at a rate of 0.85 kg/s, domestic hot water at a rate of 2.231 kg/s, chilled water at a rate of 3.931 kg/s, and electric power at a capacity of 21,530 kW. Hence, the system’s thermal, electrical, and exergy efficiencies are determined to be 7.54 %, 3.87 %, and 47 %, respectively. Furthermore, the sum unit cost of products and the levelized energy cost equal 0.0272 $/GJ and 0.17 $/kWh, correspondingly. Additionally, a net present value of 65.86 M$ and a total yearly cost of 37.52 M$ are the results of the economic assessment. The current research demonstrates a negative CO2 emission from an environmental standpoint. The attainment of negative CO2 emissions is due to using CO2 as input material in the system. Also, the system’s net present value surpasses the total annual cost by 1.75 times, mainly due to its ability to produce products like methanol, generating revenue to offset initial costs. The proposed system is ideal for geothermal energy sites near seawater, promoting environmental preservation by reducing pollutants. Finally, it is suggested that the system’s operation be optimized and an experiential setup be used for future research.

A green, facile, and practical preparation of capsaicin derivatives with thiourea structure

Capsaicin derivatives with thiourea structure (CDTS) is highly noteworthy owing to its higher analgesic potency in rodent models and higher agonism in vitro. However, the direct synthesis of CDTS remains t one or more shortcomings. In this study, we present reported a green, facile, and practical synthetic method of capsaicin derivatives with thiourea structure is developed by using an automated synthetic system, leading to a series of capsaicin derivatives with various electronic properties and functionalities in good to excellent yields.

Deposition of Pd, Pt, and PdPt Nanoparticles on TiO2 Powder Using Supercritical Fluid Reactive Deposition: Application in the Direct Synthesis of H2O2.

In this study, we investigated the catalytic properties of mono- and bimetallic palladium (Pd) and platinum (Pt) nanoparticles deposited via supercritical fluid reactive deposition (SFRD) on titanium dioxide (TiO2) powder. Transmission electron microscopy analyses verified that SFRD experiments performed at 353 K and 15.6 MPa enabled the deposition of uniform mono- and bimetallic nanoparticles smaller than 3 nm on TiO2. Electron-dispersive X-ray spectroscopy demonstrated the formation of alloy-type structures for the bimetallic PdPt nanoparticles. H2O2 is an excellent oxidizing reagent for the production of fine and bulk chemicals. However, until today, the design and preparation of catalysts with high H2O2 selectivity and productivity remain a great challenge. The focus of this study was on answering the questions of (a) whether the catalysts produced are suitable for the direct synthesis of hydrogen peroxide (H2O2) in the liquid phase and (b) how the metal type affects the catalytic properties. It was found that the metal type (Pd or Pt) influenced the catalytic performance strongly; the mean productivity of the mono- and bimetallic catalysts decreased in the following order: Pd > PdPt > Pt. Furthermore, all catalysts prepared by SFRD showed a significantly higher mean productivity compared to the catalyst prepared by incipient wetness impregnation.

Modularized Engineering of Shewanella oneidensis MR-1 for Efficient and Directional Synthesis of 5-Aminolevulinic Acid.

Shewanella oneidensis MR-1 has found widespread applications in pollutant transformation and bioenergy production, closely tied to its outstanding heme synthesis capabilities. However, this significant biosynthetic potential is still unexploited so far. Here, we turned this bacterium into a highly-efficient bio-factory for green synthesis of 5-Aminolevulinic Acid (5-ALA), an important chemical for broad applications in agriculture, medicine, and the food industries. The native C5 pathway genes of S. oneidensis was employed, together with the introduction of foreign anti-oxidation module, to establish the 5-ALA production module, resulting 87-fold higher 5-ALA yield and drastically enhanced tolerance than the wide type. Furthermore, the metabolic flux was regulated by using CRISPR interference and base editing techniques to suppress the competitive pathways to further improve the 5-ALA titer. The engineered strain exhibited 123-fold higher 5-ALA production capability than the wide type. This study not only provides an appealing new route for 5-ALA biosynthesis, but also presents a multi-dimensional modularized engineering strategy to broaden the application scope of S. oneidensis.

An inexpensive, metal-free and one-pot approach towards N-sulfonyl amidines: Identification of a chorismate mutase inhibitor with activities against S. aureus

The simple yet innovative synthetic approaches for the direct access to the diversity based unique class of compounds of potential biological interest are of considerable interest as that can greatly facilitate the efforts in bioorganic / medicinal chemistry and drug discovery. In our efforts, we have developed a metal-free, inexpensive and one-pot method for the facile and direct synthesis of N-sulfonyl amidines that were designed as inhibitors of chorismate mutase. The methodology involved POCl3-SOCl2 promoted reaction of amide with sulphonamide to afford an array of new and unique class of compounds in good to acceptable yields. The methodology is free from the use of additional organic reaction media and amenable for scale-up. Based on in vitro and in silico studies, 3g has been identified as a first example of chorismate mutase inhibitor with selective and promising activities on a range of S. aureus strains. Indeed, the docking of 3g into AlphaFold predicted structure S. aureus CM I (UniProt ID: A0A380DU97) revealed good interactions with stabilization mostly via π-anion interactions in addition to a halogen (fluorine) bond. Compound 3g is of further pharmacological interest.

A direct synthesis of 5-azidomethyl pyrimidine nucleosides via dehydroxyazidation

We have successfully developed a direct azidation method for selectively functionalizing 5-hydroxymethyl pyrimidine deoxyribonucleosides (such as 5hmdU and 5hmdC) and nucleobases. This approach yielded the corresponding 5-azidomethyl nucleobases and nucleosides (5zmdU and 5zmdC) with moderate to good yields, eliminating the requirement for converting them into more reactive halides or tosylates beforehand. The incorporated azido group demonstrated effectiveness as a chemical tag for subsequent labeling and detection by reacting with strained alkyne DBCO-acid.

Stepwise structural evolution toward robust carboranealkynyl-protected copper nanocluster catalysts for nitrate electroreduction.

Atomically precise metal nanoclusters (NCs) are emerging as idealized model catalysts for imprecise metal nanoparticles to unveil their structure-activity relationship. However, the directional synthesis of robust metal NCs with accessible catalytic active sites remains a great challenge. In this work, we achieved bulky carboranealkynyl-protected copper NCs, the monomer Cu13·3PF6 and nido-carboranealkynyl bridged dimer Cu26·4PF6, with fair stability as well as accessible open metal sites step by step through external ligand shell modification and metal-core evolution. Both Cu13·3PF6 and Cu26·4PF6 demonstrate remarkable catalytic activity and selectivity in electrocatalytic nitrate (NO3-) reduction to NH3 reaction, with the dimer Cu26·4PF6 displaying superior performance. The mechanism of this catalytic reaction was elucidated through theoretical computations in conjunction with in situ FTIR spectra. This study not only provides strategies for accessing desired copper NC catalysts but also establishes a platform to uncover the structure-activity relationship of copper NCs.

One‐step Synthesis of Organic Terminal 2D Ti3C2Tx MXene Nanosheets by Etching of Ti3AlC2 in an Organic Lewis Acid Solvent

AbstractThe surface and interface chemistry are critical for controlling the properties of two‐dimensional transition metal carbides and nitrides (MXenes). Numerous efforts have been devoted to the functionalization of MXenes with small inorganic ligands; however, few etching methods have been reported on the direct bonding of organic groups to MXene surfaces. In this work, we demonstrated an efficient and rapid strategy for the direct synthesis of 2D Ti3C2Tx MXene nanosheets with organic terminal groups in an organic Lewis acid (trifluoromethanesulfonic acid) solvent, without introducing additional intercalations. The dissolution of aluminum and the subsequent in situ introduction of trifluoromethanesulfonic acid resulted in the extraction of Ti3C2Tx MXene (T=CF3SO3−) (denoted as CF3SO3H−Ti3C2Tx) flakes with sizes reaching 15 μm and high productivity (over 70 %) of monolayers or few layers. More importantly, the large CF3SO3H−Ti3C2Tx MXene nanosheets had high colloidal stability, making them promising as efficient electrocatalysts for the hydrogen evolution reaction.

Catalytic evaluation of Ni–3%Sr-/MCM-41 in dry and steam reforming of methane

A nickel catalyst on mesoporoussilica created through a direct synthesis and modified with a strontium promoter. After conducting dry and steam reforming tests, the prepared samples characterized using the XRD, XRF, BET, TPR and HR-TEM, and then considered to study the catalyst stability and activity. And, the CH4 and CO2 conversion and ratio of H2/CO with using the Sr–Ni/MCM-41 catalyst in the DRM and SRM processes at 700 °C, were determined about (73.3% and 80.6%), (55.81% and 60.25%), and (0.88 and 3.1), respectively. Furthermore, SEM, TPR, and TPD analysis were used to characterize the utilized catalyst. The finding demonstrated a good structural order and the specific surface area (SSA) of 889.5 m2/g. The presence of a strontium enhanced nickel oxide's reducibility and strengthened its interaction with the base. Furthermore, strontium enhanced the catalytic activity.

Optimizing Membrane Reactor Structures for Enhanced Hydrogen Yield in CH4 Tri-Reforming: Insights from Sensitivity Analysis and Machine Learning Approaches

This study explores the optimization of membrane reactor configurations to enhance hydrogen production through CH4 tri-reforming. The investigation employs ceramic membranes for oxygen, vapor, and carbon dioxide distribution within the reactor bed. A differential evolution algorithm is utilized alongside cuckoo search algorithm (CSA) and support vector regression (SVR) to determine optimal values for O2/CH4, H2O/CH4, and CO2/CH4 ratios, membrane thickness, and shell pressure, with hydrogen yield as the objective function. Results demonstrate that the oxygen membrane reactor achieves the highest hydrogen yield, reaching 2.02 and 1.75 for direct methanol synthesis and Fischer-Tropsch processes, respectively, representing a 7.98% and 10.03% increase compared to the conventional tri-reforming reactor. Furthermore, CSA and SVR emerge as invaluable tools, facilitating robust optimization and predictive modeling. The CSA efficiently navigates complex solution spaces to identify optimal parameters, while SVR accurately models relationships between input variables and hydrogen yield. Incorporating these methodologies enhances the effectiveness of membrane reactor design and synthesis gas production. This study contributes to advancements in clean energy technologies by providing insights into efficient hydrogen production methods using membrane reactors.

An Efficient Synthesis of α‐Sulfonamide Phosphonates through Metal‐Free Three‐Component Reaction

A metal‐free three‐component reaction for the direct synthesis of α‐sulfonamide phosphonates involving sulfonamide derivatives, benzaldehyde derivatives, and diethyl phosphite, has been achieved with high yields using ethanol as a green solvent. This efficient method reduces reaction time and minimizes the use of excess reagents. Hitherto, no reports have been found in the literature for the direct synthesis of α‐sulfonamide phosphonates from the readily available aldehydes, diethyl phosphite, and sulfonamides, emphasizing the novelty and significance of this work.

Identifying Pd9OX as the optimum catalyst for the direct synthesis of H2O2 through microkinetic modeling with coverage effects

Identifying efficient active sites for the direct synthesis of hydrogen peroxide over Pd-based catalysts has been a subject of considerable debate. In this study, we employ particle swarm optimization method and density functional theory to explore the H2O2 synthesis mechanism on Pd, PdO, and the partially oxidized surface (Pd9OX). A comprehensive mechanism for Pd9OX is elucidated, and subsequent coverage-dependent kinetic analysis allows for a quantitative assessment of catalytic performance at the interphase. Our findings conclusively establish that the interphase between Pd and PdO represents the optimal active site. Phase diagram analysis further aids in determining stable structures under reaction conditions. At 298.15 K and under oxygen balance, the Pd9O6 surface remains stable throughout the reaction, demonstrating high activity and selectivity. This work underscores the significance of the interphase in comprehending catalytic performance and unveils promising avenues for optimizing catalyst performance by controlling reaction conditions and surface composition.

Direct Synthesis of Glycosyl Chlorides from Thioglycosides.

Reported herein is a new method for the direct synthesis of glycosyl chlorides from thioglycosides using sulfuryl chloride at rt. A variety of thioglycosides and thioimidates could be used as substrates. Both acid- and base-sensitive protecting groups were found compatible with these reaction conditions. Preliminary investigation of the reaction mechanism indicates chlorination of the leaving group at the anomeric sulfur as the key step of the reaction.

Cation Exchange in Colloidal Transition Metal Nitride Nanocrystals.

Transition metal nitride (TMN)-based nanostructures have emerged as promising materials for diverse applications in electronics, photonics, energy storage, and catalysis due to their highly desirable physicochemical properties. However, synthesizing TMN-based nanostructures with designed compositions and morphologies poses challenges, especially in the solution phase. The cation exchange reaction (CER) stands out as a versatile postsynthetic strategy for preparing nanostructures that are otherwise inaccessible through direct synthesis. Nevertheless, exploration of the CER in TMNs lags behind that in metal chalcogenides and metal phosphides. Here, we demonstrate cation exchange in colloidal metal nitride nanocrystals, employing Cu3N nanocrystals as starting materials to synthesize Ni4N and CoN nanocrystals. By controlling the reaction conditions, Cu3N@Ni4N and Cu3N@CoN core@shell heterostructures with tunable compositions can also be obtained. The Ni4N and CoN nanocrystals are evaluated as catalysts for the electrochemical oxygen evolution reaction (OER). Remarkably, CoN nanocrystals demonstrate superior OER performance with a low overpotential of 286 mV at 10 mA·cm-2, a small Tafel slope of 89 mV·dec-1, and long-term stability. Our CER approach in colloidal TMNs offers a new strategy for preparing other metal nitride nanocrystals and their heterostructures, paving the way for prospective applications.

High-Level Disordered Metal-Organic Frameworks Synthesized by Interference-Oriented Attachment for Electrochemical Anion Sieve.

Disordered MOFs seamlessly amalgamate the robust stability and pore tunability inherent in crystalline MOFs with the advantages derived from abundant defects and active sites present in amorphous structures. This study pioneers the use of the interference-oriented attachment (IOA) mechanism to meticulously craft the morphology and crystal growth of MIL-101(Cr) (Cr-MOF), resulting in the successful synthesis of a high-level disordered Cr-MOF boasting an enhanced array of active sites and exceptional electrochemical properties. The correlation between disordered structures and the electrochemical properties of MOFs are elucidated using the lattice distortion index and fractal dimension. The high-level disordered MOF electrode showcases a remarkable fluoride sieving effect, outperforming conventional fluoride removal materials with a remarkable fluoride adsorption capacity of 41.04 mgNaF gelectrodes -1. First-principles calculations, in conjunction with relevant experiments, provided further validation that the disordered structure significantly enhances the defluorination performance of the material. This study introduces a novel approach for the direct bottom-up synthesis of high-level disordered MOFs, showcasing their potential for applications in electrochemical water treatment.

Direct Synthesis of Ultrasmall PbS Nanocrystals Passivated with a Metal-Halide-Perovskite-like Monolayer

Direct Synthesis of Ultrasmall PbS Nanocrystals Passivated with a Metal-Halide-Perovskite-like Monolayer

Direct Synthesis of α-Ketoamides via Copper-Catalyzed Reductive Amidation of Nitroarenes with α-Oxocarboxylic Acids.

Nitroarenes are known for their stability, low toxicity, easy availability, and cost-effectiveness, making them one of the most fundamental chemical feedstocks. The direct utilization of nitroarenes as nitrogen sources in amidation reactions offers significant advantages over using arylamines. Herein, we disclose a streamlined method for constructing α-ketoamides through the direct coupling of nitroarenes with α-oxocarboxylic acids. This transformation obviates the need for preparing, isolating, and purifying arylamines, leading to improved efficiency, cost-effectiveness, and time savings.

Exploring High‐Pressure Polymorphism in Carbonic Acid through Direct Synthesis from Carbon Dioxide Clathrate Hydrate

AbstractCarbon dioxide (CO2) is widespread in astrochemically relevant environments, often coexisting with water (H2O) ices and thus triggering a great interest regarding the possible formation of their adducts under various thermodynamic conditions. Amongst them, solid carbonic acid (H2CO3) remains elusive, yet being widely studied. Synthetic routes followed for its production have always been characterised by drastic irradiation on solid ice mixtures or complex procedures on fluid samples (such as laser heating at moderate to high pressures). Here we report about a simpler yet effective synthetic route to obtain two diverse carbonic acid crystal structures from the fast, cold compression of pristine clathrate hydrate samples. The two distinct polymorphs we obtained, differing in the water content, have been deeply characterised via spectroscopic and structural techniques to assess their composition and their astonishing pressure stability, checked up to half a megabar, also highlighting the complex correlations between them so to compile a detailed phase diagram of this system. These results may have a profound impact on the prediction and modelisation of the complex chemistry which characterises many icy bodies of our Solar System.

Exploring High-Pressure Polymorphism in Carbonic Acid through Direct Synthesis from Carbon Dioxide Clathrate Hydrate.

Carbon dioxide (CO2) is widespread in astrochemically relevant environments, often coexisting with water (H2O) ices and thus triggering a great interest regarding the possible formation of their adducts under various thermodynamic conditions. Amongst them, solid carbonic acid (H2CO3) remains elusive, yet being widely studied. Synthetic routes followed for its production have always been characterised by drastic irradiation on solid ice mixtures or complex procedures on fluid samples (such as laser heating at moderate to high pressures). Here we report about a simpler yet effective synthetic route to obtain two diverse carbonic acid crystal structures from the fast, cold compression of pristine clathrate hydrate samples. The two distinct polymorphs we obtained, differing in the water content, have been deeply characterised via spectroscopic and structural techniques to assess their composition and their astonishing pressure stability, checked up to half a megabar, also highlighting the complex correlations between them so to compile a detailed phase diagram of this system. These results may have a profound impact on the prediction and modelisation of the complex chemistry which characterises many icy bodies of our Solar System.