B(C6F5)3-Catalyzed Aza-Friedel–Crafts Reaction of Indolizines with 2-Aryl-3H-indol-3-ones

A Friedel–Crafts reaction of indolizines with 2-aryl-3H-indol-3-ones catalyzed by B(C₆F₅)₃ is described. This protocol gives access to indolizine derivatives that are valuable building blocks in synthetic and pharmaceutical chemistry. The reaction proceeds under mild conditions, affording various C2-quaternary indolin-3-ones based on indolizine with high yields and regioselectivities. Moreover, the synthetic transformations of the target products were realized by N-methylation and trifluoromethane sulfonation.     

交互模式-电感耦合等离子体质谱(ICP-MS)法测定生态地球化学植物样品中7种金属元素

植物样品中各元素的含量,是评价土壤质量及健康的重要指标。为满足测定大批量生态地球化学植物样品中多金属元素分析要求,建立了交互模式-ICP-MS法测定植物样品中7种痕量金属元素的定量分析方法。讨论了ICP-MS的STD、KED（He）、交互模式3种方法测定植物样品中7种金属元素结果。实验结果表明：利用工作曲线法配制Hg标准溶液,更改82Se在线校正方程系数为1.83,在ICP-MS的交互模式下测定植物样品中82Se,63Cu,60Ni,66Zn,111Cd,75As、202Hg可以得到准确可靠的结果,克服了植物样品中Se和Hg元素测定的难题。基于所建方法各元素校准曲线系数＞0.999;方法检出限为0.0004~0.08mg/kg;加标回收率在96.2%-107%之间;测定GBW10010a（大米）、GBW10012（玉米）、GBW10021（豆角）3种标准物质,结果均在参考值范围内,相对标准偏差RSD＜10%。该方法前处理简单、灵敏度高、准确度高、分析速度快,适用于生态地球化学评价植物样品多金属元素同时测定。为地球化学调查工作中分析测试植物样品中金属多元素的快速测定提供了新思路。     

Reversible Switching CuII/CuI Single Sites Catalyze High-rate and Selective CO2 Photoreduction

Herein, we first design a model of reversible redox-switching metal–organic framework single-unit-cell sheets, where the abundant metal single sites benefit for highly selective CO₂ reduction, while the reversible redox-switching metal sites can effectively activate CO₂ molecules. Taking the synthetic Cu-MOF single-unit-cell sheets as an example, synchrotron-radiation quasi in situ X-ray photoelectron spectra unravel the reversible switching Cu^II/Cu^I single sites initially accept photoexcited electrons and then donate them to CO₂ molecules, which favors the rate-liming activation into CO₂^δ−, verified by in situ FTIR spectra and Gibbs free energy calculations. As an outcome, Cu-MOF single-unit-cell sheets achieve near 100 % selectivity for CO₂ photoreduction to CO with a high rate of 860 μmol g⁻¹ h⁻¹ without any sacrifice reagent or photosensitizer, where both the activity and selectivity outperform previously reported photocatalysts evaluated under similar conditions.     

Long-term super-resolution imaging of mitochondrial dynamics

Monitoring dynamics of mitochondria has become an essential approach to explore the function of mitochondria in living cells with the emergence of super-resolution fluorescence microscopy. However, long-term super-resolution imaging of mitochondria is still challenging due to the lack of photostable fluorescent probes and stable mitochondria-specific markers which are not affected by the changes of mitochondrial membrane potential. Here, we introduce a method for long-term imaging mitochondrial dynamic through the SNAP-tag fluorogenic probe based on 4-azetidinyl-naphthalimide derivatives. Using structured illumination microscopy (SIM), we observed the fusion and fission of mitochondria over a course of 16 min at 109 nm resolution. Furthermore, the interactions as well as fusion between mitochondria and lysosomes were studied during mitophagy at the nanoscale. Convincingly, the combination of SNAP-tag fluorogenic probes and super-resolution fluorescence microscopy will offer a new way to monitor dynamic mitochondria in living cells.     

MOFs/水凝胶复合材料的制备及其应用研究

金属有机框架(MOFs)具有大量的孔隙结构和活性位点,在气体吸附、催化、医疗等领域均发挥了巨大的作用。MOFs是晶体粉末,具有脆性较大、在水中易分解和不易回收等缺点,从而限制了其应用。通过MOFs与柔性高分子的复合,特别是与水凝胶的复合,极大地改善了复合材料的柔顺性、可回收和可加工性等特性,进一步拓宽了MOFs的应用领域。本文详细阐述了基于水凝胶MOFs原位生成法、MOFs /水凝胶同时生成法和水凝胶包裹MOFs法等三种不同方法制备MOFs/水凝胶复合材料的研究进展,并对上述三种制备方法的特点及其产物特征进行了总结,进一步归纳了复合材料在生物医药、催化、废水处理和气体吸附等领域的应用。最后,对MOFs/水凝胶复合材料制备方法的改进和复合材料应用前景进行了深入讨论和展望。     

O2 dissociative adsorption on the Cu‐, Ag‐, and W‐doped Al(111) surfaces from DFT computation

The O₂ adsorption and dissociation on M‐doped (M = Cu, Ag, W) Al(111) surface were studied by density functional theory. The adsorption energy of adsorbate, the average binding energy and surface energy of Al surface, and the doping energy of doping atom were calculated. All the doped atoms can be stably combined with Al atoms, while being slightly embedded in the surface to a certain depth. The TOP‐type surfaces are the most stable doped surfaces for O₂ adsorption, which is related to the orbital hybridization between the adsorbate and the surface atoms, the electronegativity, and the orbital energy level of the doping atoms. Moreover, the O atoms and doping atoms contribute significantly to the density of states (DOS), especially the O‐p orbital electrons and the d orbital electrons of doping atoms. The degree of O₂ dissociation is related to the doping atoms on Al surfaces, and the doping atoms actually resist the dissociation of O₂. W atoms have the best resistance effect on the O₂ dissociation as compared with Cu and Ag atoms, especially W‐1NN surface, which has both large barrier energy and reaction energy.     

Efficient domino strategy for synthesis of 3-substituted 1,5-dihydro-4H-pyrrolo[3,2-c]pyridin-4-one derivatives

A series of 1,5-dihydro-4H-pyrrolo[3,2-c]pyridin-4-one derivatives with 3-(4-hydroxy-2-oxo-2H-pyran-3-yl) groups were synthesized via a one-pot three-component reaction of 4-aminopyridin-2(1H)-ones, 2,2-dihydroxy-1-arylethan-1-ones, and 4-hydroxy-2H-pyran-2-ones in water. This strategy not only provides a valuable tool in the design and synthesis of new hydrogenated pyrrolo[3,2-c]pyridines but also has the advantages of inexpensive starting materials, atom and step economy, environmental friendliness, good to excellent yields, and operational simplicity. A total of 14 examples were examined to show a broad substrate scope and high yields.     

Y-Mn-O负载的Ni基催化剂用于乙酸自热重整产氢

为了有效地从生物质衍生的乙酸中获得高氢气产率,通过水热法合成了一系列的NiMnY催化剂并用于乙酸自热重整(ATR)过程中,并采用X射线衍射(XRD)、N2吸附-脱附测试、H₂程序升温还原(H₂-TPR)探究催化剂中的内在联系。在Ni_0.39Mn_0.61YO_3.11±δ催化剂中,经焙烧后形成了类钙钛矿型(Ni,Mn)YO3物相;经氢气还原后,转化为含有Mn O、Y₂O₃和高分散Ni纳米粒子的热稳定的Ni-Mn-Y-O物种。Ni_0.39Mn_0.61YO_3.11±δ具有高效稳定的产氢催化性能,乙酸转化率高达100%,氢气产率达到2.68 mol_(H₂)·mol_HAc^-1。     

High-strength and low-swelling chitosan/cellulose microspheres as a high-efficiency adsorbent for dye removal

Cellulose - Dye contamination of water supplies has a serious threat to human health, prompting the development of highly effective and eco-friendly adsorbents. In this work, polyelectrolyte...