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1.
Phys Chem Chem Phys ; 2024 Jul 16.
Article in English | MEDLINE | ID: mdl-39011574

ABSTRACT

Hydrogen energy with its advantages of high calorific value, renewable nature, and zero carbon emissions is considered an ideal candidate for clean energy in the future. The electrochemical decomposition of water, powered by renewable and clean energy sources, presents a sustainable and environmentally friendly approach to hydrogen production. However, the traditional electrochemical overall water-splitting reaction (OWSR) is limited by the anodic oxygen evolution reaction (OER) with sluggish kinetics. Although important advances have been made in efficient OER catalysts, the theoretical thermodynamic difficulty predetermines the inevitable large potential (1.23 V vs. RHE for the OER) and high energy consumption for the conventional water electrolysis to obtain H2. Besides, the generation of reactive oxygen species at high oxidation potentials can lead to equipment degradation and increase maintenance costs. Therefore, to address these challenges, thermodynamically favorable anodic oxidation reactions with lower oxidation potentials than the OER are used to couple with the cathodic hydrogen evolution reaction (HER) to construct new coupling hydrogen production systems. Meanwhile, a series of robust catalysts applied in these new coupled systems are exploited to improve the energy conversion efficiency of hydrogen production. Besides, the electrochemical neutralization energy (ENE) of the asymmetric electrolytes with a pH gradient can further promote the decrease in application voltage and energy consumption for hydrogen production. In this review, we aim to provide an overview of the advancements in electrochemical hydrogen production strategies with low energy consumption, including (1) the traditional electrochemical overall water splitting reaction (OWSR, HER-OER); (2) the small molecule sacrificial agent oxidation reaction (SAOR) and (3) the electrochemical oxidation synthesis reaction (EOSR) coupling with the HER (HER-SAOR, HER-EOSR), respectively; (4) regulating the pH gradient of the cathodic and anodic electrolytes. The operating principle, advantages, and the latest progress of these hydrogen production systems are analyzed in detail. In particular, the recent progress in the catalytic materials applied to these coupled systems and the corresponding catalytic mechanism are further discussed. Furthermore, we also provide a perspective on the potential challenges and future directions to foster advancements in electrocatalytic green sustainable hydrogen production.

2.
J Ethnopharmacol ; 334: 118521, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38969152

ABSTRACT

ETHNOPHARMACOLOGICAL RELEVANCE: Sangju Cold Granule (SJCG) is a classical traditional Chinese medicine (TCM) prescription described in "Item Differentiation of Warm Febrile Diseases". Historically, SJCG was employed to treat respiratory illnesses. Despite its popular usage, the alleviating effect of SJCG on influenza A virus infection and its mechanisms have not been fully elucidated. AIM OF THE STUDY: Influenza is a severe respiratory disease that threatens human health. This study aims to assess the therapeutic potential of SJCG and the possible molecular mechanism underlying its activity against influenza A virus in vitro and in vivo. MATERIALS AND METHODS: Ultrahigh-performance liquid chromatography (UPLC)-Q-Exactive was used to identify the components of SJCG. The 50% cytotoxic concentration of SJCG in MDCK and A549 cells were determined using the CCK-8 assay. The activity of SJCG against influenza A virus H1N1 was evaluated in vitro using plaque reduction and progeny virus titer reduction assays. RT-qPCR was performed to obtain the expression levels of inflammatory mediators and the transcriptional regulation of RIG-I and MDA5 in H1N1-infected A549 cells. Then, the mechanism of SJCG effect on viral replication and inflammation was further explored by measuring the expressions of proteins of the RIG-I/NF-kB/IFN(I/III) signaling pathway by Western blot. The impact of SJCG was explored in vivo in an intranasally H1N1-infected BALB/c mouse pneumonia model treated with varying doses of SJCG. The protective role of SJCG in this model was evaluated by survival, body weight monitoring, lung viral titers, lung index, lung histological changes, lung inflammatory mediators, and peripheral blood leukocyte count. RESULTS: The main SJCG chemical constituents were flavonoids, carbohydrates and glycosides, amino acids, peptides, and derivatives, organic acids and derivatives, alkaloids, fatty acyls, and terpenes. The CC50 of SJCG were 24.43 mg/mL on MDCK cells and 20.54 mg/mL on A549 cells, respectively. In vitro, SJCG significantly inhibited H1N1 replication and reduced the production of TNF-α, IFN-ß, IL-6, IL-8, IL-13, IP-10, RANTES, TRAIL, and SOCS1 in infected A549 cells. Intracellularly, SJCG reduced the expression of RIG-I, MDA5, P-NF-κB P65 (P-P65), P-IκBα, P-STAT1, P-STAT2, and IRF9. In vivo, SJCG enhanced the survival rate and decreased body weight loss in H1N1-infected mice. Mice with H1N1-induced pneumonia treated with SJCG showed a lower lung viral load and lung index than untreated mice. SJCG effectively alleviated lung damage and reduced the levels of TNF-α, IFN-ß, IL-6, IP-10, RANTES, and SOCS1 in lung tissue. Moreover, SJCG significantly ameliorated H1N1-induced leukocyte changes in peripheral blood. CONCLUSIONS: SJCG significantly reduced influenza A virus and virus-mediated inflammation through inhibiting the RIG-I/NF-kB/IFN(I/III) signaling pathway. Thus, SJCG could provide an effective TCM for influenza treatment.

3.
J Am Chem Soc ; 146(23): 16194-16202, 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38832699

ABSTRACT

Although progress has been made in enantioselective hydroboration of di- and trisubstituted alkenes over the past decades, enantioselective hydroboration of tetrasubstituted alkenes with high diastereo- and enantioselectivities continues as an unmet challenge since the 1950s due to its extremely low reactivity and the difficulties to simultaneously control the regio- and stereoselectivity of a tetrasubstituted alkene. Here, we report highly regio-, diastereo-, and enantioselective catalytic hydroboration of diverse acyclic tetrasubstituted alkenes. The delicate interplay of an electron-rich rhodium complex and coordination-assistance forms a highly adaptive catalyst that effectively overcomes the low reactivity and controls the stereoselectivity. The generality of the catalyst system is exemplified by its efficacy across various tetrasubstituted alkenes with diverse steric and electronic properties.

4.
Chem Sci ; 15(15): 5711-5722, 2024 Apr 17.
Article in English | MEDLINE | ID: mdl-38638220

ABSTRACT

The boom of aqueous Zn-based energy storage devices, such as zinc-iodine (Zn-I2) batteries, is quite suitable for safe and sustainable energy storage technologies. However, in rechargeable aqueous Zn-I2 batteries, the shuttle phenomenon of polyiodide ions usually leads to irreversible capacity loss resulting from both the iodine cathode and the zinc anode, and thus impinges on the cycle lifespan of the battery. Herein, a nontoxic, biocompatible, and economical polymer of polyvinyl alcohol (PVA) is exploited as an electrolyte additive. Based on comprehensive analysis and computational results, it is evident that the PVA additive, owing to its specific interaction with polyiodide ions and lower binding energy, can effectively suppress the migration of polyiodide ions towards the zinc anode surface, thereby mitigating adverse reactions between polyiodide ions and zinc. Simultaneously, the hydrogen bond network of water molecules is disrupted due to the abundant hydroxyl groups within the PVA additive, leading to a decrease in water activity and mitigating zinc corrosion. Further, because of the preferential adsorption of PVA on the zinc anode surface, the deposition environment for zinc ions is adjusted and its nucleation overpotential increases, which is favorable for the dense and uniform deposition of zinc ions, thus ensuring the improvement of the performance of the Zn-I2 battery. This investigation has inspired the development of a user-friendly and high-performance Zn-I2 battery.

5.
Eur J Pharmacol ; 970: 176508, 2024 May 05.
Article in English | MEDLINE | ID: mdl-38493913

ABSTRACT

Necroptosis is a pivotal contributor to the pathogenesis of various human diseases, including those affecting the nervous system, cardiovascular system, pulmonary system, and kidneys. Extensive investigations have elucidated the mechanisms and physiological ramifications of necroptosis. Among these, protein phosphorylation emerges as a paramount regulatory process, facilitating the activation or inhibition of specific proteins through the addition of phosphate groups to their corresponding amino acid residues. Currently, the targeting of kinases has gained recognition as a firmly established and efficacious therapeutic approach for diverse diseases, notably cancer. In this comprehensive review, we elucidate the intricate role of phosphorylation in governing key molecular players in the necroptotic pathway. Moreover, we provide an in-depth analysis of recent advancements in the development of kinase inhibitors aimed at modulating necroptosis. Lastly, we deliberate on the prospects and challenges associated with the utilization of kinase inhibitors to modulate necroptotic processes.


Subject(s)
Neoplasms , Protein Kinases , Humans , Phosphorylation , Protein Kinases/metabolism , Necroptosis , Neoplasms/drug therapy , Receptor-Interacting Protein Serine-Threonine Kinases/metabolism , Apoptosis
6.
J Colloid Interface Sci ; 665: 573-581, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38552574

ABSTRACT

Designing efficient and cost-effective electrocatalysts for overall water splitting remains a major challenge in hydrogen production. Herein, ammonia was introduced to pyrophosphate chelating solution assisted Ni particles preferential plating on porous Fe substrate to form coral-like Ni/NiFe-Pyro electrode. The pyrophosphate with multiple complex sites can couple with nickel and iron ions to form an integrated network structure, which also consists of metallic nickel due to the introduction of ammonia. The large network structure in Ni/NiFe-Pyro significantly enhances the synergistic effect between nickel and iron and then improves the electrocatalytic performance. As a result, the coral-like Ni/NiFe-Pyro@IF exhibits good electrocatalytic activity and stability for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The electrolyzer assembled with Ni/NiFe-Pyro@IF as cathode and anode just needs a low water-splitting voltage of 1.54 V to obtain the current density of 10 mA cm-2. Meanwhile, the stability test of Ni/NiFe-Pyro@IF is performed at the current densities ranging from 10 to 400 mA cm-2 for 50 h without any significant decay, indicating robust catalytic stability for overall water splitting. This strategy for synthesizing metal/metal pyrophosphate composites may provide a new avenue for future studies of efficient bifunctional electrocatalysts.

7.
Mater Horiz ; 10(10): 4270-4277, 2023 Oct 02.
Article in English | MEDLINE | ID: mdl-37556212

ABSTRACT

The selective two-electron electrochemical oxygen reduction reaction (ORR) for hydrogen peroxide (H2O2) production is a promising and green alternative method to the current energy-intensive anthraquinone process used in industry. In this study, we develop a single-atom catalyst (CNT-D-O-Fe) by anchoring defect-stabilized and oxygen-coordinated iron atomic sites (Fe-O4) onto porous carbon nanotubes using a local etching strategy. Compared to O-doped CNTs with vacancy defects (CNT-D-O) and oxygen-coordinated Fe single-atom site modifying CNTs without a porous structure (CNT-O-Fe), CNT-D-O-Fe exhibits the highest H2O2 selectivity of 94.4% with a kinetic current density of 13.4 mA cm-2. Fe-O4 single-atom sites in the catalyst probably contribute to the intrinsic reactivity for the two-electron transfer process while vacancy defects greatly enhance the electrocatalytic stability. Theoretical calculations further support that the coordinated environment and defective moiety in CNT-D-O-Fe could efficiently optimize the adsorption strength of the *OOH intermediate over the Fe single atomic active sites. This contribution sheds light on the potential of defect-stabilized and oxygen-coordinated single-atom metal sites as a promising avenue for the rational design of highly efficient and selective catalysts towards various electrocatalytic reactions.

8.
Materials (Basel) ; 16(11)2023 Jun 01.
Article in English | MEDLINE | ID: mdl-37297267

ABSTRACT

In the construction process of an asphalt concrete impermeable core wall, the interlayer bonding of the core wall is the weak link of the core wall structure and also the focus of construction, so it is important to carry out research on the influence of interlayer bonding temperature on the bending performance of an asphalt concrete core wall. In this paper, we study whether asphalt concrete core walls could be treated with cold-bonding by fabricating small beam bending specimens with different interlayer bond temperatures and conducting bending tests on them at 2 °C. The effect of temperature variation on the bending performance of the bond surface under the asphalt concrete core wall is studied through experimental data analysis. The test results show that the maximum value of porosity of bituminous concrete specimens is 2.10% at lower bond surface temperature of -25 °C, which does not meet the specification requirement of less than 2%. The bending stress, strain, and deflection of bituminous concrete core wall increase with the increase of bond surface temperature, especially when the bond surface temperature is less than -10 °C. If the lower bonding surface temperature is less than 10 °C, the upper layer of asphalt mixture with large grain size aggregate cannot be effectively buried in the low bond surface, resulting in flat fracture and brittle damage to the specimen, which is detrimental to construction quality; therefore, the bonding surface should be heated so that the temperature of the bottom bonding surface is 30 °C. If the lower bonding surface temperature is 10 °C or above, no heating is required.

9.
Small ; 19(30): e2300437, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37029572

ABSTRACT

Anthropogenic nitrate pollution has an adverse impact on the environment and human health. As part of a sustainable nitrate management strategy, electrochemical denitrification is studied as an innovative strategy for nutrients recycling and recovering. It is, however, challenging to selectively electro-reduce nitrate with low-concentration for ammonia. Herein, the photo-deposition of size-defined Ru nanoclusters (NCs, average size: ≈1.66 nm) on TiO2 nanotubes (NTs) is demonstrated, which show improved performance for nitrate-to-ammonia electroreduction with a maximum yield rate of ≈600 µg h-1  cm-2 and a faradic efficiency (FE) of > 90.0% across a broad range of potentials in comparison with electrodeposited Ru nanoparticles (NPs, average size: ≈23.78 nm) on TiO2 NTs. Experimental and theoretical evidence further suggests the small-size Ru NCs with the intrinsically enhanced selectivity and activity because of the strong metal/substrate interaction and unsaturated coordination state. The findings highlight the size effect on Ru-based catalyst supported on metal oxides, a versatile catalytic model, which allows the regulation of hydrogen adsorption to favor ammonia production over the competing hydrogen evolution reaction.

10.
J Colloid Interface Sci ; 642: 120-128, 2023 Jul 15.
Article in English | MEDLINE | ID: mdl-37001451

ABSTRACT

The exploration of high-performance electrocatalysts for the oxygen evolution reaction (OER) is crucial and urgent for the fast development of green and renewable hydrogen energy. Herein, an ultra-fast and energy-efficient preparation strategy (microwave-assisted rapid in-situ pyrolysis of organometallic compounds induced by carbon nanotube (CNT)) is developed to obtain iron/carbon (Fe/C) heterogeneous materials (Fe/Fe3C particles wrapped by carbon coating layer). The thickness of the carbon coating layer can be adjusted by changing the content and form of carbon in the metal sources during the fast preparation process. Fe/Fe3C-A@CNT using iron acetylacetonate as metal sources possesses unique Fe/C heterogeneous, small Fe/Fe3C particles encapsulated by the thin carbon coating layer (1.77 nm), and obtains the optimal electron penetration effect. The electron penetration effect derives from the redistribution of charge between the surface carbon coating layer and inner Fe/Fe3C nanoparticles efficiently improving both catalytic activity and stability. Therefore, Fe/Fe3C-A@CNT shows efficient OER catalytic activity, just needing a low overpotential of 292 mV to reach a current density of 10 mA cm-2, and long-lasting stability. More importantly, the unique control strategy for carbon thickness in this work provides more opportunity and perspective to prepare robust metal/carbon-based catalytic materials at the nanoscale.

11.
J Colloid Interface Sci ; 629(Pt B): 1003-1014, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36208601

ABSTRACT

Developing low-cost electrocatalysts with excellent activity is significant for accelerating the slow oxygen evolution reaction (OER). In this work, an effective electrocatalyst is prepared via the cross-linked effect and reconstruction strategy based on inexpensive transition metals (Fe, Co, and Ni) and phytic acid (PA). The feasibility of utilizing the cross-linked effect and reconstruction strategy is due to that PA molecules with strongly electronegative phosphoric acid groups possess a great deal of complexing sites, which can facilitate the formation of large cross-linked network by randomly complexing Fe, Co and Ni ions. And the carboatomic rings in PA molecules will reconstructed as carbon-matrix when PA molecules decompose. The above structural evolution of large cross-linked network and reconstructing process is rigorously analyzed through the characterization methods such as XPS. These analysis results indicate that FeCoNi-PA-300 possesses a high degree of amorphization, an abundant nanoporous structure, and a small nanoparticle size, resulting in a large electrochemically active area. Consequently, FeCoNi-PA-300 just needs low overpotentials of about 271 mV and 286 mV to obtain the current densities of 50 and 100 mA cm-2, respectively. Meaningfully, this synthetic method is a general strategy to meliorate the OER activity and electrical conductivity of other catalysts.

12.
J Colloid Interface Sci ; 631(Pt B): 182-190, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36401926

ABSTRACT

Aqueous rechargeable Ni/Fe batteries are appropriate energy storage devices for portable and wearable electronics due to their outstanding safety and cost-effectiveness. However, their energy storage properties are limited by the sluggish kinetics of iron-based anodes. Herein, we design and construct a high-performance iron-based material with a hierarchical structure developed by electrodepositing iron oxide (Fe2O3) nanosheets on titanium carbide (Ti3C2Tx) MXene nanoplates modified carbon fiber (3D-MXene/Fe2O3). Taking advantage of the interaction between Fe2O3 and the terminal functional groups on Ti3C2Tx MXene, such a hierarchical structure offers improved conductivity, enhanced ion-diffusion paths, and high electrochemical stability. The fabricated 3D-MXene/Fe2O3 anode delivers a high volumetric specific capacity of 38.2 mAh cm-3, and improved capacity retention. After being coupled with NiCoO cathode, the fibrous Ni/Fe battery shows a maximum volumetric specific capacity of 35.1 mAh cm-3 and an extraordinary energy density of 56.2 mWh cm-3. Meanwhile, the as-prepared Ni/Fe battery confirms good cycling durability (92.9% for 12,500 cycles), and mechanical flexibility also verifies the potential practical application of our device. Thus, this study can provide a powerful route toward high-performance anodes for next-generation wearable energy storage devices.

13.
ChemSusChem ; 16(2): e202201815, 2023 Jan 20.
Article in English | MEDLINE | ID: mdl-36397292

ABSTRACT

The use of gel thermoelectric chemical cells to capture low-grade heat for conversion to electricity is an attractive approach. However, there are few studies on whether the distribution of redox species in the electrolyte has an effect on the performance of cells. Herein, this concern was discussed by constructing a novel gel thermoelectric chemical cell (Cu-C-cg). Using cellulose-like rice paper as a separator, a concentration gradient of electrolyte was carefully constructed, so that the concentration of potassium ferrocyanide gradually decreased from the hot electrode to the cold electrode while the concentration of potassium ferricyanide gradually increased. Through electrochemical measurement and analysis, it was found that the thermoelectric performance of this cell outperformed the cell without electrolyte concentration gradients. Meanwhile, this performance could be enhanced by the use of asymmetric electrodes composed of copper foil and carbon electrodes. After optimizing the conditions, the open-circuit voltage, output power, and Seebeck coefficient of the Cu-C-cg cell at 12 K temperature difference were 0.450 V, 183 µW, and 7.82 mV K-1 , respectively. This work not only provides a novel idea in gel-based cell design but also an excellent thermoelectric chemical cell.

14.
J Colloid Interface Sci ; 605: 906-915, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34375785

ABSTRACT

The search for ultrafast and simple methods to fabricate non-noble metal catalysts to boost electrocatalytic oxygen reduction reaction (ORR) is still ongoing. Herein, we demonstrate a one-step microwave-assisted heating method to prepare copper nitride/iron/iron carbide nanoparticle hybrids (CuNC/Fe/Fe3C/CNT). This ultrafast heating method induces plentiful carbon-wrapped metal and Fe3C nanoparticles that are attached to the surface of CNT and scattered nanosheets. The CuNC/Fe/Fe3C/CNT exhibit a half-wave potential (E1/2) of 0.886 V toward the ORR in alkaline solution, with 220 mV more positive E1/2 than that of CuNC/CNT and Fe/Fe3C/CNT respectively. The activity of as-prepared catalysts is discussed by investigating their structures and compositions and their relationship with the ORR performance. Detailed analysis results disclose that the high activity of the CuNC/Fe/Fe3C/CNT catalysts could be attributed to the interaction of CuNC and Fe/Fe3C species. To be specific, as the electron donor, Fe/Fe3C nanoparticles induce electron localization and promote the formation of Cu (δ + )-NC (0 < Î´ < 2), therefore leading to the improvement of the ORR performance. This work may offer an ultrafast way to construct efficient catalysts with enhanced ORR performance.


Subject(s)
Carbon , Copper , Catalysis , Oxygen
15.
ACS Appl Mater Interfaces ; 13(48): 57411-57421, 2021 Dec 08.
Article in English | MEDLINE | ID: mdl-34823361

ABSTRACT

Aqueous Ni/Fe alkaline batteries with features of low cost and high safety show great potential for application in portable and wearable electronics. However, the poor kinetics of the Fe-based anode greatly limits the large-scale applications of Ni/Fe batteries. Herein, we report an interconnected 3D conductive network with carbon-coated nanostructured iron/iron oxide (3D-Fe/Fe2O3@C) as an efficient anode for a flexible Ni/Fe battery. A hydrogel precursor is used to molecularly link and confine Fe3+ to spatial networks, resulting in a uniform dispersion of Fe/Fe2O3-heterostructured nanoparticles. Theoretical investigations reveal regulated potential loss and improved delocalized carrier density as a result of carbon coating and the mixed metal/metal oxide structure. In addition to these merits, due to the regulated wettability and electroactive surface areas, the 3D-Fe/Fe2O3@C anode with a high mass loading delivers an extraordinary areal capacity of 3.07 mA h cm-2, as well as the boosted rate capability and Coulombic efficiency. When coupled with the NiCo2O4 cathode, the flexible quasi-solid-state Ni/Fe battery exhibits an admirable energy density of 15.53 mW h cm-3 and a maximum power density of 761.91 W h cm-3. The good stability after 20,000 cycles and severe mechanical deformations of the as-fabricated Ni/Fe battery imply it as a promising flexible energy storage device for practical applications.

16.
Transl Lung Cancer Res ; 10(8): 3616-3626, 2021 Aug.
Article in English | MEDLINE | ID: mdl-34584861

ABSTRACT

BACKGROUND: Prolonged air leak (PAL) is one of the most common postoperative complications after lung surgery. This study aimed to identify risk factors of PAL after lung resection and develop a preoperative predictive model to estimate its risk for individual patients. METHODS: Patients with pulmonary malignancies or metastasis who underwent pulmonary resection between January 2014 and January 2018 were included. PAL was defined as an air leak more than 5 days after surgery, risk factors were analyzed. Forward stepwise multivariable logistic regression analysis was performed to identify independent risk factors, and a derived nomogram was built. Data from February 2018 to September 2018 were collected for internal validation. RESULTS: A total of 1,511 patients who met study criteria were enrolled in this study. The overall incidence of PAL was 9.07% (137/1,511). Age, percent forced expiratory volume in 1 second, surgical type, surgical approach and smoking history were included in the final model. A nomogram was developed according to the multivariable logistic regression results. The C-index of the predictive model was 0.70, and the internal validation value was 0.77. The goodness-of-fit test was non-significant for model development and internal validation. CONCLUSIONS: The predictive model and derived nomogram achieved satisfied preoperative prediction of PAL. Using this nomogram, the risk for an individual patient can be estimated, and preventive measures can be applied to high-risk patients.

17.
Angew Chem Int Ed Engl ; 60(34): 18599-18604, 2021 08 16.
Article in English | MEDLINE | ID: mdl-34125475

ABSTRACT

We present herein an unprecedented diastereoconvergent synthesis of vicinal diamines from diols through an economical, redox-neutral process. Under cooperative ruthenium and Lewis acid catalysis, readily available anilines and 1,2-diols (as a mixture of diastereomers) couple to forge two C-N bonds in an efficient and diastereoselective fashion. By identifying an effective chiral iridium/phosphoric acid co-catalyzed procedure, the first enantioconvergent double amination of racemic 1,2-diols has also been achieved, resulting in a practical access to highly valuable enantioenriched vicinal diamines.

18.
Nat Commun ; 12(1): 3776, 2021 06 18.
Article in English | MEDLINE | ID: mdl-34145273

ABSTRACT

Chiral tertiary boronic esters are important precursors to bioactive compounds and versatile synthetic intermediates to molecules containing quaternary stereocenters. The development of conjugate boryl addition to α,ß-unsaturated amide has been hampered by the intrinsic low electrophilicity of the amide group. Here we show the catalytic asymmetric synthesis of enantioenriched tertiary boronic esters through hydroboration of ß,ß-disubstituted α,ß-unsaturated amides. The Rh-catalyzed hydroboration occurs with previously unattainable selectivity to provide tertiary boronic esters in high enantioselectivity. This strategy opens a door for the hydroboration of inert Michael acceptors with high stereocontrol and may provide future applications in the synthesis of biologically active molecules.

19.
Chempluschem ; 86(1): 184-190, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33481358

ABSTRACT

Electrodeposition is an effective method to prepare various materials. We have established a bipolar electrodeposition system assisted by a constant magnetic field to fabricate a Co/Fe/Ni phytate catalyst with good electrocatalytic activity for overall water splitting. The effects of magnetic and electric fields on the catalytic properties of the material were studied. The catalyst prepared with an N-pole magnetic field (NPMF) exhibited good overall water splitting performance. Benefiting from the synergistic effect of the Co/Fe/Ni-phytate and the advantages of the N-pole magnetic field the NPMF electrode has a continuous 25 hours high-efficiency hydrogen evolution and oxygen evolution reaction at a current density of 100 mA cm-2 in1.0 M KOH compared with commercial RuO2 and Pt/C. Bipolar electrodeposition with a constant magnetic field is thus an efficient means to fabricate electrocatalytic water splitting catalysts.

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