Efficient Method For Synthesis Research Articles

Influence of various concentrations of chloroauric acid on the fabrication of gold nanoparticles: Green synthesis using Elaeis guineensis Jacq leaf extract and characterizations

This work studies a green method for synthesizing gold nanoparticles (AuNPs) using Elaeis Guineensis Jacq. (oil palm) leaf extract (EGE) using a precursor of chloroauric acid (HAuCl4). The influence of various HAuCl4 concentrations on the formation of AuNPs by the green method was investigated. Characterization methods were employed to analyze the optical properties, size, shape, structure, and SERS applicability of the AuNPs. The findings suggest that EGE contains biomolecules like flavonoids and phenols, which fulfil the roles of reducing and capping agents during the synthesis of AuNPs. The AuNPs were fabricated spectroscopically at around 525 nm and validated by UV–Vis spectrophotometer. FT-IR result presents that the stretching vibrations of the hydroxyl (O–H) molecule are indicated by the large peak absorption at 3336 cm−1, demonstrating the O–H functional groups in the derivatives of phenols. The carbonyl (CO) stretching vibrations, generated by the carboxylic acid in flavonoids and phenols, exhibited a robust absorption at 1602 cm−1. An optimal HAuCl4 concentration of 0.69 mM resulted in AuNPs with uniform spherical morphology and a 10–30 nm size range confirmed by TEM analysis. This concentration also led to the strongest Raman intensity, indicating the potential of these biogenic AuNPs for SERS applications. Overall, the study demonstrates a sustainable and efficient method for AuNP synthesis using a readily available plant extract, paving the way for their use in advanced sensing technologies.

Synthesis of Quinolines Catalyzed by Bidentate Terpyridine Mn(I) Complex

ABSTRACTA method for efficient synthesis of quinolines via acceptorless dehydrogenative condensation is presented. A series of quinolines are obtained by the coupling reaction of 2‐aminobenzyl alcohols with secondary alcohols in the presence of bidentate terpyridine Mn(I) complex in good to excellent yields. Pleasantly, various substituted secondary alcohols and substituted aminobenzyl alcohols all provide quinolines with good functional group tolerance. Importantly, this investigation also provides a green and environmentally friendly protocol for constructing heterocyclic compounds.

Asymmetric Synthesis of Chiral Aliphatic α‐Tertiary Aminonitriles via Organocatalytic Isomerization of Cyanoketimines

Comprehensive SummaryChiral α‐tertiary aminonitriles are valuable synthetic intermediates. They are also found in various structures of biologically active molecules. Therefore, numerous reports of catalytic asymmetric synthesis of chiral α‐aminonitriles continuously emerged during the past few decades. Great strides have been made for the synthesis of chiral α‐aryl and α‐branched alkyl aminonitriles. However, efficient methods for catalytic asymmetric synthesis of chiral α‐linear alkyl aminonitriles remain limited. We herein report a new synthetic approach to chiral α‐tertiary alkyl aminonitriles via catalytic asymmetric isomerization of cyanoketimines. The synthetic value of this method was illustrated by application to a concise catalytic asymmetric synthesis of vildagliptin.

Asymmetric Synthesis of Chiral Calix[4]arenes with Both Inherent and Axial Chirality via Cobalt-Catalyzed Enantioselective Intermolecular C-H Annulation.

Inherently chiral calixarenes have garnered significant attention due to their distinctive properties, yet the development of efficient catalytic asymmetric synthesis methods remains a critical challenge. Herein, we report the asymmetric synthesis of calix[4]arenes featuring inherent or both inherent and axial chirality via a cobalt-catalyzed C-H activation/annulation strategy in high yield with excellent enantio- and diastereoselectivity (up to > 99% ee and > 20:1 dr). Electrooxidation was also suitable for this transformation to obviate the sacrificial metal oxidants, underscoring the environmentally friendly potential of this approach. A key octahedral cobaltacycle intermediate was synthesized and characterized, providing valuable insights into the mode of enantio- and diastereocontrol of this protocol. Noteworthy photoluminescence quantum yields of up to 0.94 were measured, underscoring the potential of these compounds in the domain of organic fluorescent materials.

Exploring the molarity of Lithium Fluoride in minimally intensive layer delamination (MILD) method for efficient room temperature synthesis of high quality Ti3C2Tx free-standing film

In recent years, MXene has become the most demanding material in the 2D family, leading to their increased use in research for a diverse range of applications, such as energy storage, water purification, optoelectronics, electromagnetic interference (EMI) shielding and medicine. However, recent research has made it increasingly important to synthesize high-quality MXene in a safe, reliable, fast, reproducible, and good-yielding single-step method. To achieve high-quality MXene by etching the MAX phase precursors, it is very important to critically optimize synthesis parameters, such as etching method, etchant concentrations, temperature, time, etc. Minimally intensive layer delamination (MILD) method for MXene synthesis using Lithium Fluoride (LiF) salt and hydrochloric (HCl) acid seems to be a better choice in the context of improved performance in different applications as well as its scalability and reproducibility. Here, the molar ratio of HCL/LIF is critical for Aluminium etching at room temperature to produce a high-quality MXene with = O, -OH, -F termination groups in the MILD method. However, in case of MILD method the effect of LiF/HCL concentrations on quality of MXene need to be addressed. In this study, we focus on room temperature etching of Ti3AlC2 using MILD method to synthesize quasi two-dimensional carbide (Ti3C2) MXene. The influence of molarity concentration of etchants (LiF and HCl) on quality of MXene has been thoroughly investigated. Different molar concentrations of Lithium Fluoride (LiF) with fixed HCL concentration were tested at room temperature for 24 h in the etching process. The crystal structure, microstructure and composition of the MXene were characterized using X-ray diffraction, Raman spectroscopy, and electron microscopy. Flexible free-standing MXene film with largest shift in the characteristic (002) peak, indicating large interplanar spacing, has been successfully achieved repeatedly for an optimum molar concentration of etchants at room temperature.

Mild and Catalytic Synthesis of Pyrroles from Vinyl Ethynylethylene Carbonates.

A tandem remote propargylic amination/ring closure/aromatization reaction of vinyl ethynylethylene carbonates and amines has been developed, successfully constructing pyrrole derivatives. The reaction features mild conditions, high regioselectivity, high yields, and good functional group tolerance, making it an efficient method for pyrrole synthesis. Importantly, a variety of substrates containing natural product skeletons could also be compatibly and efficiently converted into pyrroles under the reaction conditions.

Dual-Factor-Controlled Dynamic Precursors Enable On-Demand Thermoset Degradation and Recycling.

Thermosets are well known for their advantages such as high stability and chemical resistance. However, developing sustainable thermosets with degradability and recyclability faces several principal challenges, including reconciling the desired characteristics during service with the recycling and reprocessing properties required at the end of life, establishing efficient methods for large-scale synthesis, and aligning with current manufacturing process. Here a general strategy is presented for the on-demand degradation and recycling of thermosets under mild conditions utilizing dynamic precursors with dual-factor-controlled reversibility. Specifically, dynamic triazine crosslinkers are introduced through dynamic nucleophilic aromatic substitution (SNAr) into the precursor polyols used in polyurethane (PU) synthesis. Upon removal of the catalyst and alcohol, the reversibility of SNAr is deactivated, allowing for the use of standard PU polymerization techniques such as injection molding, casting, and foaming. The resulting cyanurate-crosslinked PUs maintain high stability and diverse mechanical properties of traditional crosslinked PUs, yet offer the advantage of easy on-demand depolymerization for recycling by activating the reversibility of SNAr under specific but mild conditions-a combination of base, alcohol, and mild heat. It is envisioned that this approach, involving the pre-installation of dual-factor-controlled dynamic crosslinkers, can be broadly applied to current thermosetting plastic manufacturing processes, introducing enhancedsustainability.

Synthesis of silacycles via metal hydrogen atom transfer and radical-polar crossover mechanism

In this study, we have developed an efficient method for silacycle synthesis using metal hydride hydrogen atom transfer (MHAT) and radical-polar crossover (RPC) mechanism. Allylic silanols were synthesized via one-step condensation and then cyclized under mild conditions using N-fluoropyridinium tetrafluoroborate (Me3NFPY·BF4) as the oxidant under cobalt catalysis. This approach yielded five-, six-, and seven-membered silacycles with high selectivity, with the six-membered rings being the favored products. Density functional theory (DFT) calculations provided valuable insights into the reaction mechanisms and highlighted the role of ring strain in determining product selectivity. This study demonstrated the effectiveness of combining MHAT/RPC methodologies with silicon tethering, thus offering a robust platform for expanding the use of silicon-based strategies in synthetic chemistry.

One-step synthesis of Pt@(CrMnFeCoNi)3O4 high entropy oxide catalysts through flame spray pyrolysis

High entropy oxides (HEOs) show great prospects in catalysis owing to their widely tunable component structures and ease of combination with active metals. However, the development of HEO catalysts is limited by the lack of efficient synthesis methods due to the difficulty of homogeneously mixing at least five elements. In this work, flame spray pyrolysis (FSP) is successfully employed to synthesize (CrMnFeCoNi)3O4 HEO with a single phase spinel structure in one step, which is verified by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and energy-dispersive X-ray spectroscopy (EDS). Taking CO catalytic oxidation as a probe reaction, the Pt@(CrMnFeCoNi)3O4 HEO catalyst synthesized by FSP in one step is compared with the catalyst whose Pt is impregnated on (CrMnFeCoNi)3O4 HEO support. The FSP-made catalysts have a higher catalytic reaction rate and better redox ability, which lowers the temperature of complete CO conversion by nearly 100 °C. Furthermore, it can be observed that the flame parameters can be optimized to modify the particle size and oxygen vacancies of the HEO nanoparticles, thus enhancing the catalytic performances. This work demonstrates that FSP is an effective method for the one-step synthesis of HEO catalysts with excellent catalytic performance, providing a new perspective for the synthesis of HEO-based materials.

Photocatalytic Decarboxylative Fluorination by Quinone-Based Isoreticular Covalent Organic Frameworks.

The strategic incorporation of fluorine atoms into molecules has become a cornerstone of modern pharmaceuticals, agrochemicals, and materials science. Herein, we have developed a covalent organic framework (COF)-based, robust photocatalyst that enables the photofluorodecarboxylation reaction of diverse carboxylic acids, producing alkyl fluorides with remarkable efficiency. The catalytic activity of an anthraquinone-based COF catalyst TpAQ outperforms other structurally analogous β-ketoenamine COFs. Through comprehensive control experiments, photoluminescence, and electrochemical studies, we have elucidated the unique features of the material and the mechanistic pathway. This in-depth understanding has paved the way for optimizing the reaction conditions and achieving high yields of alkyl fluorides. The versatility of this protocol extends to a broad range of aliphatic acids with diverse functional groups and heterocycles. It also enabled the late-stage diversification of anti-inflammatory drugs and steroid derivatives. This opens up exciting possibilities for synthesizing novel pharmaceuticals and functionalized molecules. The methodology was also generalized to other light-mediated decarboxylative halogenation reactions. Furthermore, our method demonstrates scalability under both batch and continuous flow conditions, offering a promising approach for large-scale production. Additionally, the TpAQ catalyst exhibits exceptional durability and can be reused multiple times without significant activity loss (>80% yield after the eighth cycle), making it a sustainable and cost-effective solution. This work lays the foundation for developing efficient and sustainable light-driven synthesis methods using COFs as photocatalysts with potential applications beyond alkyl halide synthesis.

Deep Eutectic Solvent (DES)‐Mediated Green Approach for Synthesis of Benzothiazole Tethered Pyrazoles: Antimicrobial Properties and Molecular Docking Insights

AbstractThe escalating incidence of bacterial resistance to commonly prescribed antibiotics underscores the urgent need for the rapid development of innovative antibacterial medications. Heterocyclic compounds, particularly nitrogen‐containing heterocycles like pyrazoles and thiazoles, have garnered attention for their diverse biological activities, including antimicrobial properties. Here, we present a green and efficient multicomponent synthesis method for fourteen novel benzothiazole‐tethered pyrazole derivatives. Utilizing the deep eutectic solvent glycerol/K2CO3 as a base‐catalytic reaction medium at 70 °C, this synthesis approach yielded promising compounds exhibiting substantial antimicrobial activity against various pathogenic microorganisms such as Staphylococcus aureus, Bacillus cereus, and Candida albicans. Among these, 4‐(benzo[d]thiazol‐2‐yl)‐3‐(4‐nitrophenyl)‐1‐phenyl‐1H‐pyrazol‐5‐amine emerged as the most promising candidate, showcasing significant inhibitory potentials with CZD values of 24 mm, 21 mm, and 26 mm for S. aureus, B. cereus, and C. albicans, respectively. Molecular docking studies further supported the experimental observations, revealing the high binding affinity of the compound to the nitroreductase enzyme with a binding score of −8.5 kcal/mol. These findings underscore the potential of these synthesized compounds as antimicrobial agents and suggest avenues for future research in exploring their structure‐activity relationships and therapeutic applications in combating bacterial infections.

Photochemical oxidative coupling of thiols to disulfides using Bi quantum dots: Mild and efficient catalysis

Herein, we present an efficient synthesis method utilizing Bi quantum dots (QDs) as catalysts for the photochemical oxidative coupling of thiols to disulfides under mild conditions. The protocol offers low catalyst loading, simplicity in reaction setup as well as high efficiency. Aromatic thiols and aliphatic thiols are successfully transformed into disulfides with good to quantitative yields, demonstrating tolerance to various substituents and heterocycles. Additionally, the protocol extends to the synthesis of asymmetric disulfides and allows for gram-scale synthesis.

Efficient triethylamine sensing achieved by in-situ Zn2+ doping regulated Mo-MOFs derived MoO3/ZnMoO4 heterostructures

Triethylamine (TEA) poses severe safety hazards to industrial production and human health. To accurately detect TEA concentrations and rapidly warn of leakage, a simple reflux condensation method was deployed to successfully incorporate Zn2+ in situ into Mo-MOFs precursor in a green, safe, and time-efficient synthesis condition. Subsequently, through calcination, MoO3/ZnMoO4-X (MMZ-X) were prepared, which exhibited an increased number of defects and enriched porosity, facilitating the access and interaction of TEA with adsorption sites. Simultaneously, rationally built in situ MoO3/ZnMoO4 heterostructures accelerated carrier migration and induced a drastic resistive change. MMZ-2 demonstrated outstanding TEA sensing performance, exhibiting extremely high sensitivity (R = 572.3, 100 ppm), along with superior selectivity, repeatability and stability, rapid response and recovery times, and a low detection limit. Moreover, the key intrinsic parameters of the heterostructure on the atomic scale were determined by density functional theory (DFT) calculations, providing a detailed elucidation of the sensing enhancement mechanism of the MoO3/ZnMoO4 heterostructure. The simple and efficient synthesis method and the related mechanistic analysis pave a new path for designing high-performance TEA gas sensors with practical applications.

A high-speed method to obtain Ni-Zn ferrite nanoparticles by microwave hydrotalcite decomposition for magnetic applications

Nanoparticles of Zn0.375Ni0.625Fe2O4 ferrite were successfully synthesized using an innovative, rapid, and efficient synthesis method based on microwave-assisted hydrotalcite decomposition, enabling nanoparticle crystallization in less than 15 minutes. A single composition was studied to better assess the impact of the synthesis method on structural, morphological, and magnetic properties. This new synthesis route was compared with the traditional ceramic method. The prepared hydrotalcite was analyzed by high-resolution transmission electron microscopy (HRTEM), identifying hydrotalcite diffraction planes consistent with selected area electron diffraction (SAED) and X-ray diffraction (XRD) patterns. The decomposition phases of the hydrotalcite were identified by simultaneous thermogravimetric and differential thermal analysis (DTA/TG). After hydrotalcite decomposition, the ferrite obtained was analyzed by XRD, confirming a single-phase cubic structure. Scanning electron microscopy (SEM) micrographs revealed nanoparticles less than 100 nm in size with the new method and larger than 2 µm with the traditional route. At a temperature of 5 K, the M-H graph obtained with a superconducting quantum interference device (SQUID) indicated that the spinel-type ferrite exhibited a smooth ferrimagnetic behavior, which was also corroborated by electron paramagnetic resonance (EPR). Magnetic saturation values of 105.73 emu/g were obtained in the synthesis microwave-assisted hydrotalcite decomposition and 51.49 emu/g in the traditional synthesis, representing an increase of over 100 %. The two synthesis methods were also compared using density functional theory (DFT) calculations, confirming the influence of morphology on magnetic properties, obtained thanks to different synthesis methods. These results indicate that the synthesized Ni-Zn spinel ferrite nanoparticles can be used in high-frequency applications, such as ceramic induction plates.

Methods for rapid and efficient synthesis of dendrimers, a new impetus for the development of dendrimer materials science

Methods for rapid and efficient synthesis of dendrimers, a new impetus for the development of dendrimer materials science

Temperature-Controlled Synthesis of Thiophenol-VBXs from EBXs and Thiophenols

Vinylbenziodoxolones (VBXs) is an important electrophilic alkene synthon, however, the synthesis of cis-thiophenol-VBXs reagents from ethynylbenziodoxolones (EBXs) and thiophenols is still facing challenge. Herein, we firstly explored an efficient method for synthesis of cis-thiophenol-VBXs in excellent yield with excellent regio- and stereoselectivity from EBXs and thiophenols under temperature-controlled condition.

Stoichiometric Study on Ion Composition of a Precursor in Chemical Bottom-Up Synthesis for Peroxo-Titanate.

Layered alkali titanates of the lepidocrocite type are gaining enormous interest in various fields owing to their unique properties. These materials are mainly synthesized through a hydrothermal alkali treatment. However, this method uses a highly concentrated alkali solution, which has high environmental impacts and is therefore unsuitable for mass synthesis. Herein, we propose an efficient method for the large-scale synthesis of layered sodium titanate structures (Na2-x H x Ti2O5) using a recently reported bottom-up chemical process. The effects of the Na:Ti molar ratio in the peroxo-titanium complex ion precursor on the products are investigated through stoichiometric calculations for a molar ratio range of 10:1-1:1. The optimal ratio for the complete ionization of TiH2 (which is the starting material) to form the peroxo-titanium complex ion is found to be 1.1:1. The amount of alkali raw material required is 99.6% lower than that required in the traditional hydrothermal method. The crystal structures and morphologies of the samples are almost identical regardless of the Na:Ti molar ratio. The precursor-derived peroxo bonds narrow the energy band gaps of the layered titanates even when the amount of titanium ions dissolved in the precursor increases. The proposed method is not only an efficient synthetic route for mass production but also has potential applications in the development of photofunctional materials.

In-situ synthesis of Fe3O4@Fe3C nanoparticles with heterostructures embedded in the N-doped porous carbon for high-performance lithium ion batteries

Metal oxides (Fe3O4) have attracted immense attention as high-capacity anode materials for high-performance electrochemical energy storage systems. However, the large structural change and sluggish reaction kinetics in the lithiation and delithiation reactions critically limit their practical development. Here, we design a novel composite consisting of Fe3O4@Fe3C nanoparticles embedded in N-doped porous carbon (Fe3O4@Fe3C-NPC) for lithium ion batteries. Benefiting from the synergistic effect of heterostructures, the Fe3O4@Fe3C-NPC delivers high reversible capacities (911.9 mAh g−1 at 0.2 A g−1, 319.6 mAh g−1 at 5.0 A g−1). The formed heterointerfaces can build an internal electric field, which help to improve reaction kinetics with fast ion diffusion kinetics and low charge transfer resistance. Furthermore, the Fe3O4@Fe3C-NPC//LiFePO4 full cell also displays great performance. The structural design concept and efficient synthesis method in the work can be extended to construct metal oxide/carbide heterostructures for anode materials.

Photoelectrocatalytic Synthesis of Urea from Carbon Dioxide and Nitrate over a Cu2O Photocathode.

Transformation of carbon dioxide and nitrate ions into urea offers an attractive route for both nitrogen fertilizer production and environmental remediation. However, achieving this transformation under mild conditions remains challenging. Herein, we report an efficient photoelectrochemical method for urea synthesis by co-reduction of carbon dioxide and nitrate ion over a Cu2O photocathode, delivering urea formation rate of 29.71±2.20 μmol g-1 h-1 and Faradaic efficiency (FE) of 12.90±1.15 % at low external potential (-0.017 V vs. reversible hydrogen electrode). Experimental data combined with theoretical calculations suggest that the adsorbed CO* and NO2* species are the key intermediates, and associated C-N coupling is the rate-determining step. This work demonstrates that Cu2O is an efficient catalyst to drive co-reduction of CO2 and NO3 - to urea under light irradiation with low external potential, showing great opportunity of photoelectrocatalysis as a sustainable tool for value-added chemical synthesis.

Photoelectrocatalytic Synthesis of Urea from Carbon Dioxide and Nitrate over a Cu2O Photocathode

AbstractTransformation of carbon dioxide and nitrate ions into urea offers an attractive route for both nitrogen fertilizer production and environmental remediation. However, achieving this transformation under mild conditions remains challenging. Herein, we report an efficient photoelectrochemical method for urea synthesis by co‐reduction of carbon dioxide and nitrate ion over a Cu2O photocathode, delivering urea formation rate of 29.71±2.20 μmol g−1 h−1 and Faradaic efficiency (FE) of 12.90±1.15 % at low external potential (−0.017 V vs. reversible hydrogen electrode). Experimental data combined with theoretical calculations suggest that the adsorbed CO* and NO2* species are the key intermediates, and associated C−N coupling is the rate‐determining step. This work demonstrates that Cu2O is an efficient catalyst to drive co‐reduction of CO2 and NO3− to urea under light irradiation with low external potential, showing great opportunity of photoelectrocatalysis as a sustainable tool for value‐added chemical synthesis.