Latest ArticlesHerein, we developed the first example of copper-catalyzed silicon radical-initiated 1,4-silylcyanation of unactivated 1,3-enynes, which provided an efficient method to access CN-bearing tri- and tetra-substituted homoallenylsilane derivatives in high yields with excellent regioselectivities. This protocol featured good functional group compatibility and broad substrate scopes, enabling the formation of C-Si bond under cheap copper catalyst with a low loading. Furthermore, this means showed potential application value in the late-stage functionalization of natural products.
Oxygen evolution reaction (OER) is one of the most important half-reactions related to metal-air batteries, fuel cells, and water-splitting. Due to the sluggish kinetic and multi-electron transfer, catalysts appear to be particularly important for the OER. Knowing the reaction mechanism is fundamental to developing new catalysts and improving OER efficiency. In this work, phase transition and atomic reconstruction on CoO (111) plane were revealed through ex-situ diffraction methods and X-ray absorption spectroscopy. At the same time, the electronic state evolution of Co(Ⅱ)/Co(Ⅲ) during the OER process has also been concluded by analyzing the magnetic properties. This work shows that during the OER process, Co(Ⅲ) experiences surface electron rearrangement from IS (intermediate-spin state) to LS (low-spin state) and then returns to IS/HS (high-spin state) under high voltage region. This work provides a new view to reveal the reaction mechanism through the magnetic property and it can be extended to more magnetic 3d transition metals for future catalyst design.
The first total synthesis of marine sesquiterpene (hydro)quinone meroterpenoids dysideanones A and E–G (1 and 4–6) has been accomplished in an enantioselective and divergent way. The sesquiterpene fragment and the aromatic moiety were efficiently connected via a site-selective and diastereoselective intermolecular alkylation of Wieland–Miescher ketone derivative 9 and benzyl bromide 10. The core 6/6/6/6-fused backbone of dysideanones was efficiently constructed through an intramolecular radical cyclization reaction. Dysideanone G (6) was easily prepared on a gram-scale and dysideanones A, E, and F (1, 4, and 5) were divergently transformed from dysideanone G (6) in one or two steps
Aryl ketones as photolabile protecting group (PPG) to modify purine imines is a novel nucleic acid protection strategy. Especially, photoprotection of N7-guanosine is the first reported photoprotected nucleoside that can affect the Hoogsteen recognition site of guanosine. However, the mechanism, which is pivotal to high efficiency of photorelease and applications of PPGs in biological and medical systems, is unclear. Here, a detailed deprotection mechanism of benzophenone protected guanosine (BP-Guo) at N7 position is reported. Upon irradiation, BP-Guo populates to singlet state, which generates 3[BP]-Guo via intersystem crossing process. Thereafter, triplet energy transfer competes with hydrogen atom transfer forming BP-3[Guo] and ketyl-Guo, respectively. Both species break CN bond to release guanosine. These results provide deeper insights into exploiting improved strategies for photo-protecting nucleic acids. In particular, the TTET pathway could trigger well-known cyclization reactions that brings about DNA mutagenic adducts. The latter should be avoided in developing improved strategies for photoprotecting nucleic acids.
In recent years, the development of wafer-level GaN nanowires photocatalyst loaded onto silicon substrates has progressed rapidly depending on its simplicity of instrumentation, collection and separation from the water. Accordingly, the wafer-level GaN-based nanowires (GaN NWs) photocatalyst can be a fabulous candidate for the application in the field of photocatalytic hydrogen evolution reaction (PHER) and provides a novel route to address the environmental and energy crisis. Herein, a range of innovative strategies to improve the performance of GaN NWs photocatalyst are systematically summarized. Then, the solar-to-hydrogen conversion efficiency, the characteristics of GaN NWs system, the cost of the origin material required, as well as the stability, activity and the corrosion resistance to seawater are discussed in detail as some of the essential conditions for advancing its large-scale industry-friendly application. Last but not least, we provide the potential application of this system for splitting seawater to produce hydrogen and point out the direction for overcoming the barriers to future industrial-scale implementation.
Conversion-type anode materials are highly desirable for Na-ion batteries (NIBs) due to their high theoretical capacity. Nevertheless, the active materials undergo severe expansion and pulverization during the sodiation, resulting in inferior cycling stability. Herein, a self-supporting three-dimensional (3D) graphene sponge decorated with Fe2O3 nanocubes (rGO@Fe2O3) is constructed. Specifically, the 3D graphene sponge with resilience and high porosity benefits to accommodate the volume expansion of the Fe2O3 nanocubes and facilitates the rapid electrons/ions transport, enabling spatial confinement to achieve outstanding results. Besides, the free-standing rGO@Fe2O3 can be directly used as an electrode without additional binders and conductive additives, which helps to obtain a higher energy density. Based on the total mass of the rGO@Fe2O3 material, the rGO@Fe2O3 anode presents a specific capacity of 859 mAh/g at 0.1 A/g. It also delivers an impressive cycling performance (327 mAh/g after 2000 cycles at 1 A/g) and a superior rate capacity (162 mAh/g at 20 A/g). The coin-type Na3V2(PO4)3@C//rGO@Fe2O3 NIB exhibits an energy density of 265.3 Wh/kg. This unique 3D ionic/electronic conductive network may provide new strategies to design advanced conversion-type anode materials for high-performance NIBs.
Excessive Fe3+ ion concentrations in wastewater pose a long-standing threat to human health. Achieving low-cost, high-efficiency quantification of Fe3+ ion concentration in unknown solutions can guide environmental management decisions and optimize water treatment processes. In this study, by leveraging the rapid, real-time detection capabilities of nanopores and the specific chemical binding affinity of tannic acid to Fe3+, a linear relationship between the ion current and Fe3+ ion concentration was established. Utilizing this linear relationship, quantification of Fe3+ ion concentration in unknown solutions was achieved. Furthermore, ethylenediaminetetraacetic acid disodium salt was employed to displace Fe3+ from the nanopores, allowing them to be restored to their initial conditions and reused for Fe3+ ion quantification. The reusable bioinspired nanopores remain functional over 330 days of storage. This recycling capability and the long-term stability of the nanopores contribute to a significant reduction in costs. This study provides a strategy for the quantification of unknown Fe3+ concentration using nanopores, with potential applications in environmental assessment, health monitoring, and so forth.
Herein, an alkyne-terminated acid/base responsive amphiphilic [2]rotaxane shuttle was synthesized, and then modified onto the glass surface through "click" reaction. The XPS N 1s spectrum and contact-angle measurement were performed to prove the successful immobilization. The amphiphilic [2]rotaxane functionalized surface presented controllable wettability responding to external acid-base stimuli. This bistable rotaxane modified material system promoted the practical application of molecular machines.
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