Stereoselective Research Articles

Alterations in driving ability and their relationship with morphometric magnetic resonance imaging indicators in patients with amnestic mild cognitive impairment and Alzheimer's disease.

Drivers with dementia are at a higher risk of motor vehicle accidents. The characteristics of driving behaviour of patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD) have not been fully elucidated. We investigated driving ability and its relationship with cognitive function and magnetic resonance imaging (MRI) morphometry indicators. The driving abilities of 19 patients with AD and 11 with amnestic MCI (aMCI) were evaluated using a driving simulator. The association between each driving ability parameter and the Mini-Mental State Examination (MMSE) score or voxel-based specific regional analysis system for AD (VSRAD) was assessed. Patients with AD made a significantly higher number of operational errors than those with aMCI in attention allocation in the complex task test (P = 0.0008). The number of operational errors in attention allocation in the complex task test significantly and negatively correlated with MMSE scores in all participants (r = -0.4354, P = 0.0162). The decision time in the selective reaction test significantly and positively correlated with the severity and extent of medial temporal structural atrophy (r = 0.4807, P = 0.0372; r = 0.4862, P = 0.0348; respectively). An increase in the operational errors for attention allocation in the complex task test could be a potential indicator of progression from aMCI to AD. Atrophy of the medial temporal structures could be a potential predictor of impaired judgement in driving performance in aMCI and AD. A driving simulator could be useful for evaluating the driving abilities of individuals with aMCI and AD.

ChemoDOTS: a web server to design chemistry-driven focused libraries.

In drug discovery, the successful optimization of an initial hit compound into a lead molecule requires multiple cycles of chemical modification. Consequently, there is a need to efficiently generate synthesizable chemical libraries to navigate the chemical space surrounding the primary hit. To address this need, we introduce ChemoDOTS, an easy-to-use web server for hit-to-lead chemical optimization freely available at https://chemodots.marseille.inserm.fr/. With this tool, users enter an activated form of the initial hit molecule then choose from automatically detected reactive functions. The server proposes compatible chemical transformations via an ensemble of encoded chemical reactions widely used in the pharmaceutical industry during hit-to-lead optimization. After selection of the desired reactions, all compatible chemical building blocks are automatically coupled to the initial hit to generate a raw chemical library. Post-processing filters can be applied to extract a subset of compounds with specific physicochemical properties. Finally, explicit stereoisomers and tautomers are computed, and a 3D conformer is generated for each molecule. The resulting virtual library is compatible with most docking software for virtual screening campaigns. ChemoDOTS rapidly generates synthetically feasible, hit-focused, large, diverse chemical libraries with finely-tuned physicochemical properties via a user-friendly interface providing a powerful resource for researchers engaged in hit-to-lead optimization.

Tailoring the A and B site of Fe-based perovskites for high selectivity in the reverse water-gas shift reaction

The reverse water-gas shift reaction (rWGS) is of particular interest as it is the first step to producing high-added-value products from carbon dioxide (CO2) and renewable hydrogen (H2), such as synthetic fuels or other chemical building blocks (e.g. methanol) through a modified Fischer-Tropsch process. However, side reactions and material deactivation issues, depending on the conditions used, still make it challenging. Efforts have been put into developing and improving scalable catalysts that can deliver high selectivity while at the same time being able to avoid deactivation through high temperature sintering and/or carbon deposition. Here we design a set of perovskite ferrites specifically tailored to the hydrogenation of CO2 via the reverse water-gas shift reaction. We tailor the oxygen vacancies, proven to play a major role in the process, by partially substituting the primary A-site element (Barium, Ba) with Praseodymium (Pr) and Samarium (Sm), and also dope the B-site with a small amount of Nickel (Ni). We also take advantage of the exsolution process and manage to produce highly selective Fe-Ni alloys that suppress the formation of any by-products, leading to up to 100% CO selectivity.

Cu-based nano-material catalysts for electrochemical carbon dioxide reduction reaction (CO2RR)

With the emergence of the global energy crisis and global climate change, renewable energy systems, such as fuel cells that turn off energetic oxygen and carbon cycles, are becoming increasingly important. Carbon dioxide reduction reaction (CO_2 RR) is an important electrocatalytic process on the gas diffusion electrode of CO_2 electrolyzer, which has been paid more and more attention by researchers. The problems of high cost, low efficiency, weak selectivity and stability of the carbon dioxide reduction reaction (CO_2 RR) also continue to be solved. Catalysts are considered a viable way to solve these problems. The Cu-based nanomaterial catalyst has been proven to have a good positive effect on the reaction. In this paper, the current research results of Cu-based nanomaterials on CO_2 RR were reviewed, and the catalytic effects of several different Cu-based nanomaterials on CO_2 RR reactions were compared. This paper collected the researches on the catalytic effect of copper-based nanomaterials on carbon dioxide reduction reactions in the past ten years, and found that most copper-based nanomaterials can improve the efficiency of the reactions and show good selectivity. The aim of this paper is to provide a possible catalytic direction for the improvement of carbon dioxide reduction reactions in industry

Empowering University Students with Cutting-Edge True Wireless Stereo Selection: A Comparative Analysis of Simple Additive Weighting and TOPSIS Algorithms

Currently, there are a lot of Solid-State Drives or SSDs that are running in the market. Each SSD can come with different features and prices from one another. Hence, this can confuse buyers planning to purchase one for their PC or laptop. It also applies to university students who depend on laptops to do college work and run on a limited budget. Any mistake in deciding which SSD to use can be costly. Henceforth, this paper aims to help decide what SSD would be best for an average university student. Two algorithms will determine which SSDs are best for university students to buy. The algorithms used are Simple Additive Weighting and Technique for Order of Preference by Similarity to Ideal Solution. The results of these algorithms are used to show the top three best SSDs for university students. Therefore, university students can make an informed choice based on the results from both algorithms.

Electrocatalysis‐driven sustainable plastic waste upcycling

AbstractWith large quantities and natural resistance to degradation, plastic waste raises growing environmental concerns in the world. To achieve the upcycling of plastic waste into value‐added products, the electrocatalytic‐driven process is emerging as an attractive option due to the mild operation conditions, high reaction selectivity, and low carbon emission. Herein, this review provides a comprehensive overview of the upgrading of plastic waste via electrocatalysis. Specifically, key electrooxidation processes including the target products, intermediates and reaction pathways in the plastic electro‐reforming process are discussed. Subsequently, advanced electrochemical systems, including the integration of anodic plastic monomer oxidation and value‐added cathodic reduction and photo‐involved electrolysis processes, are summarized. The design strategies of electrocatalysts with enhanced activity are highlighted and catalytic mechanisms in the electrocatalytic oxidation of plastic waste are elucidated. To promote the electrochemistry‐driven sustainable upcycling of plastic waste, challenges and opportunities are further put forward.

Investigating the Sole Olefin-Based Cycle in Small-Cage MCM-35-Catalyzed Methanol-to-Olefins Reactions.

Small-pore zeolites catalyze the methanol-to-olefins (MTO) reaction via a dual-cycle mechanism, encompassing both olefin- and aromatic-based cycles. Zeolite topology is crucial in determining both the catalytic pathway and the product selectivity of the MTO reaction. Herein, we investigate the mechanistic influence of MCM-35 zeolite on the MTO process. The structural properties of the as-synthesized MCM-35 catalyst, including its confined cages (6.19 Å), were characterized, confirming them as the catalytic centers. Then, the MTO reactions were systematically performed and investigated over a MCM-35 catalyst. Feeding pure methanol to the reactor yielded minimal MTO activity despite the formation of some aromatic species within the zeolite. The results suggest that the aromatic-based cycle is entirely suppressed in MCM-35, preventing the simultaneous occurrence of the olefin-based cycle. However, cofeeding a small amount of propene in methanol can obviously enhance the methanol conversion under the same studied reaction conditions. Thus, the exclusive operation of the olefin-based cycle in the MTO reaction, independent of the aromatic-based cycle, was demonstrated in MCM-35 zeolite.

Oxygen reduction reaction platinum group metal-free electrocatalysts derived from spent coffee grounds

The annual generation of coffee waste has overtaken 6 million metric tons, becoming a serious environmental problem. Herein, we report the fabrication of bimetallic electrocatalysts synthesized by 1) pyrolyzing spent coffee grounds (SCGs) at 400, 600, 800 and 1000 °C, 2) activating the as-obtained char with KOH and 3) functionalizing the activated carbon with iron(II) and manganese(II) phthalocyanine. The final electrocatalysts showed a high degree of amorphousness, defectivity (increasing with temperature) and high specific surface area (up to 1820 m2 g−1). In half-cell compartment (0.1 M KOH electrolyte), the top-notch material in terms of oxygen reduction reaction (ORR) activity and selectivity was CFeMn_600, which showed the same half-wave potential (E1/2) compared to Pt/C standard along with a lower peroxide production. These outstanding results could be attributed to a high surface area, a Fe-Mn synergy, and an abundance of C-N defects. The performance of CFeMn_600 as a cathode material in alkaline exchange membrane fuel cells (AEMFC) showed an open circuit voltage (OCV) of 0.890 V and power density of 30 mW cm−2. Notwithstanding, this research is one of few cases where a waste-derived electrocatalyst is tested in a real AEMFC, thus becoming a pioneer in the fuel cell study of waste-derived electrode materials.

Perspectives on the highly selective oxidation of copper-mediated C3N4-BiVO4 organic-inorganic hybrid catalysts and the efficient generation of reactive oxygen species

Singlet oxygen (1O2) is a kind of reactive oxygen species (ROS) with both oxidizability and selectivity. The construction of 1O2 is the key to improve the selectivity of various organic reactions. In this study, Cu/C3N4-BiVO4 (CCN-BVO) ternary system significantly improved the catalytic effect of selective oxidation of glycerol to prepare high value chemical dihydroxyacetone (DHA). At the same time, CCN-BVO also has a strong environmental catalytic effect, and the decomposition effect of liquid phase organic pollutants can reach more than 90 % within 2 h. The superior ROS production capacity of CCN-BVO, particularly its ability to produce 1O2, has been confirmed by electron spin resonance (ESR) and quenching experiments as the reason for its excellent catalytic effect. Electrochemical characterization and X-ray photoelectron spectroscopy (XPS) proved that Cu can be used as an intermediary to accelerate electron conduction, and can also effectively construct defects to improve oxygen absorption efficiency, thus effectively increasing ROS yield. This study also theoretically confirmed the reaction path of glycerol catalysis through DFT calculation, which provided a theoretical basis for the subsequent design of efficient catalytic materials.

Unveiling the Untapped Potential of Bertagnini's Salts in Microwave-Assisted Synthesis of Quinazolinones.

Microwave-assisted organic synthesis (MAOS) has emerged as a transformative technique in organic chemistry, significantly enhancing the speed, efficiency, and selectivity of chemical reactions. In our research, we have employed microwave irradiation to expedite the synthesis of quinazolinones, using water as an eco-friendly solvent and thereby adhering to the principles of green chemistry. Notably, the purification of the product was achieved without the need for column chromatography, thus streamlining the process. A key innovation in our approach is using aldehyde bisulfite adducts (Bertagnini's salts) as solid surrogates of aldehydes. Bertagnini's salts offer several advantages over free aldehydes, including enhanced stability, easier purification, and improved reactivity. Green metrics and Eco-Scale score calculations confirmed the sustainability of this approach, indicating a reduction in waste generation and enhanced sustainability outcomes. This methodology facilitates the synthesis of a diverse array of compounds, offering substantial contributions to the field, with potential for widespread applications in pharmaceutical research and beyond.

Ozone Strong Water Dosing as Optimized Ozonation Process for Micropollutants Reduction in Wastewater Treatment Plants

ABSTRACT Growing concern over potential ecotoxicological problems caused by micropollutants (MPs) in water has led to the application of adsorptive and oxidative advanced treatment technologies at European wastewater treatment plants (WWTPs). Direct dosage of gaseous ozone via diffusers or pump-injection systems is the most common large-scale process applied in water and wastewater treatment. Studies point out that MP removal may take place via the direct, very selective reaction with the ozone molecule as well as the indirect reaction with the very reactive but nonselective hydroxyl radicals. Several process parameters and set-ups may affect the MPs elimination and inhibit or even cause the formation of transformation products (TPs) such as bromate. This work compares an alternative ozone application procedure (the so-called ‘ozone strong water’ dosing – OSW) with standard systems regarding MP elimination, ozone consumption, reaction time, and required plant space. A full-scale OSW system was installed and operated at the WWTP Duisburg-Vierlinden. A significant reduction in the time required to achieve the maximum possible elimination was observed for all six MPs investigated, with a hydraulic reaction time of 8 min. According to a theoretical calculation, the reactor volume could be reduced by two-thirds of the installed volume.

Electrochemical carbon monoxide reduction at high current density: Cell configuration matters

Electrochemical carbon monoxide reduction (COR) is an important link between the electrochemical CO2-to-CO reduction technology and the renewable production of C2+ chemicals. Along with the development of catalyst materials for selective and efficient COR, it is imperative to optimize electrolysis conditions and cell parameters to efficiently reduce CO at industrially relevant current density and produce concentrated product streams. This study focuses on understanding fundamental differences in reaction selectivity during COR, when the same Cu catalyst was used in three different cell configurations, namely, microfluidic, hybrid anode zero-gap, and zero-gap electrolysers. In all cases, ethylene, acetate, ethanol, and propanol formation was confirmed at industrially relevant current densities (0.5–1.2 A cm−2) at reasonable cell voltages, albeit with subtle differences. The local chemical environment at the electrode/electrolyte interface is very different in each configuration leading to different product distribution and product crossover to the anode. This stresses the importance of cell architecture and implies that comparing the catalytic activity of a catalyst studied with different cell configurations can lead to inconsistent conclusions.

Solvent Effects on Heterogeneous Catalysis for the Selective Hydrogenation

AbstractSolvent effects add a new dimension for tuning the activity and selectivity of heterogeneous catalytic reactions, which is extensively employed in the hydrogenation of unsaturated compounds with multiple functional groups. In this concept, we briefly summarize recent developments on how the solvent effects affect the catalytic performance from the following aspects: 1) the polarity of the solvent can influence the interaction between the solvent and the reactant or intermediate; 2) the composition of mixed solvent can influence the reactivity of the reactant or intermediate; 3) solvent effect varies with the metal identity and support; 4) the solvent can induce surface modification of the supported catalysts. This summarization will provide insights into the rational development of efficient and selective heterogeneous hydrogenation catalytic system to realize the precise synthesis of desired chemicals.

Cobalt-and-Nitrogen-Doped Carbon Nanoparticle Catalysts for Selective Hydrogen Transfer Reactions

Cobalt-and-Nitrogen-Doped Carbon Nanoparticle Catalysts for Selective Hydrogen Transfer Reactions

Bond Selective Photochemistry at Metal Nanoparticle Surfaces: CO Desorption from Pt and Pd.

The use of visible photon fluxes to influence catalytic reactions on metal nanoparticle surfaces has attracted attention based on observations of reaction mechanisms and selectivity not observed under equilibrium heating. These observations suggest that photon fluxes can selectively impact the rates of certain elementary steps, creating nonequilibrium energy distributions among various reaction pathways. However, quantitative studies validating these hypotheses on metal nanoparticle surfaces are lacking. We examine the influence of continuous wave visible photon fluxes on the CO desorption rates from 1 to 2 nm diameter Pt and Pd nanoparticle surfaces supported on γ-Al2O3. Temperature-programmed desorption measurements quantified via diffuse reflectance infrared Fourier transform spectroscopy demonstrate that visible photon fluxes significantly enhanced the rate of CO desorption from Pt nanoparticles in a wavelength-dependent manner. 440 nm photons most efficiently promoted CO desorption from Pt nanoparticle surfaces, aligning with the excitation energy for the interfacial electronic transition within the Pt-CO bond. Conversely, visible photon fluxes had no measurable influence on CO desorption rates from Pd nanoparticle surfaces after accounting for photon-induced heating. Density functional theory calculations demonstrate that the Pt-CO bond exhibits a narrower LUMO resonance, stronger coupling between the photoexcitation and forces induced on the metal-C bond, and vibrational energy dissipation that more effectively couples to desorption as compared to Pd-CO. These results demonstrate the specificity photons provide in facilitating chemical reactions on metal nanoparticle surfaces and substantiate the idea that photon fluxes can steer processes and outcomes of catalytic reactions in ways not achievable by equilibrium heating.

Transition-Metal-Catalyzed Direct Arylation of Ammonia

AbstractIn the past few decades, transition-metal-catalyzed direct amination of aryl halides with ammonia has attracted significant attention from chemists because of its broad substrate scope, good functional group compatibility, and high reaction selectivity. Herein, recent examples of transition-metal-catalyzed syntheses of aniline derivatives starting from aryl halides are reviewed.1 Introduction2 Heat-Driven Transition-Metal-Catalyzed Amination of Aryl Electrophiles2.1 Palladium-Catalyzed Amination2.2 Copper-Catalyzed Amination2.3 Nickel-Catalyzed Amination3 Light-Driven Transition-Metal-Catalyzed Amination of Aryl Electrophiles4 Conclusion and Outlook

Solar‐Light‐Driven Photocatalytic Oxidative Coupling of Phenol Derivatives over Bismuth‐Based Porous Metal Halide Perovskites

AbstractThe selective oxidative coupling of phenol derivatives, involving carbon‐carbon (C−C) and carbon‐oxygen (C−O) bond formation, has emerged as a critical approach in the synthesis of natural products. However, achieving precise control over the selectivity in coupling reactions of unsubstituted phenols utilizing solar light as the driving force remains a big challenge. In this study, we report a series of porous Cs3Bi2X9 (X=Cl, Br, I) photocatalysts with tailored band gaps and compositions engineered for efficient solar‐light‐driven oxidative phenol coupling. Notably, p‐Cs3Bi2Br9 exhibited about 73 % selectivity for C−C coupling, displaying a high formation rate of 47.3 μmol gcat−1 h−1 under solar radiation. Furthermore, this approach enables control of the site‐selectivity for phenol derivatives on Cs3Bi2X9, enhancing C−C coupling. The distinctive porous structure and appropriate band‐edge positions of Cs3Bi2Br9 facilitated efficient charge separation, and surface interaction/activation of phenolic hydroxyl groups, resulting in the kinetically preferred formation of C−C over C−O bond. Mechanistic insights into the reaction pathway, supported by comprehensive control experiments, unveiled the crucial role of interfacial charge transfers and Lewis acid Bi sites in stabilizing phenolic intermediates, thereby directing the regioselectivity of diradical couplings and resulting in the formation of unsymmetrical biphenols.

Solar-Light-Driven Photocatalytic Oxidative Coupling of Phenol Derivatives over Bismuth-Based Porous Metal Halide Perovskites.

The selective oxidative coupling of phenol derivatives, involving carbon-carbon (C-C) and carbon-oxygen (C-O) bond formation, has emerged as a critical approach in the synthesis of natural products. However, achieving precise control over the selectivity in coupling reactions of unsubstituted phenols utilizing solar light as the driving force remains a big challenge. In this study, we report a series of porous Cs3Bi2X9 (X=Cl, Br, I) photocatalysts with tailored band gaps and compositions engineered for efficient solar-light-driven oxidative phenol coupling. Notably, p-Cs3Bi2Br9 exhibited about 73 % selectivity for C-C coupling, displaying a high formation rate of 47.3 μmol gcat -1 h-1 under solar radiation. Furthermore, this approach enables control of the site-selectivity for phenol derivatives on Cs3Bi2X9, enhancing C-C coupling. The distinctive porous structure and appropriate band-edge positions of Cs3Bi2Br9 facilitated efficient charge separation, and surface interaction/activation of phenolic hydroxyl groups, resulting in the kinetically preferred formation of C-C over C-O bond. Mechanistic insights into the reaction pathway, supported by comprehensive control experiments, unveiled the crucial role of interfacial charge transfers and Lewis acid Bi sites in stabilizing phenolic intermediates, thereby directing the regioselectivity of diradical couplings and resulting in the formation of unsymmetrical biphenols.

Insight into Impacts of π-π Assembly on Phthalocyanine Based Heterogeneous Molecular Electrocatalysis.

Electrochemical CO2 reduction (CO2R) to feedstocks competes with the hydrogen evolution reaction (HER). Cobalt phthalocyanine (CoPc) immobilized onto carbon driven by π-π interaction represents a classical type of heterogeneous molecular catalyst for CO2R. However, the impacts of π conjugation on the electrocatalysis have not been clarified. Herein, the electrochemical properties of CoPc were investigated by comparison of its analogue to 2,3-naphthalocyanine cobalt (NapCo) having extended π conjugation. It is found that CoPc is redox-active on carbon to provide low oxidized Co sites for improving the CO2R activity and selectivity, while NapCo on carbon turned out to be redox-inert leading to lower performance. In addition, the redox-mediated mechanism for CO2R on CoPc tends to operate with increasing electrolyte alkalinity, which further enhances the reaction selectivity. We speculated that moderate π conjugation allows the redox-mediated mechanism on CoPc, which is critical to promote CO2R performance while depressing the competing HER.

Time-resolved spectroscopic investigation for the practical application of a photocatalytic air purifier

The photocatalytic efficiency for removing volatile organic compounds (VOCs) is significantly influenced by operational parameters like humidity and flow velocity, exhibiting notable and inconsistent fluctuations in both lab-scale and large-scale demonstrations. In this study, operando spectroscopy and isotope analysis were employed to investigate the correlation between humidity levels and degradation of gaseous acetaldehyde using TiO2 photocatalysts, aiming to demonstrate the scaling-up of photocatalytic air purifier. It was observed that rate constants for the mineralization of acetaldehyde rapidly decreased by 30% as relative humidity increased from 25% to 80% in the flow system (with an air velocity, v = 0.78 m/s). However, batch system showed smaller change with only a 10% reduction of the rate constant. Humidity fluctuations were more pronounced under high-speed conditions and were amplified in air purifier (v = 3.8 m/s). Time-resolved operando spectroscopy using an 13C isotope of acetaldehyde revealed that humidity’s distinct role in dark adsorption and photocatalytic reactions. Water was found to inhibit the formation of crotonaldehyde during aldol condensation reaction in dark condition. Moreover, water suppressed photocatalytic mineralization by inhibiting acetate oxidation to formate. These findings provide valuable insights for improving realistic air purification processes, underscoring the importance of identifying key intermediates and controlling humidity to enhance the selectivity of gaseous pollutant oxidation reactions.