1α-羟基去氢表雄酮的合成

本文以1,4-雄烯二酮为起始原料,经羰基保护、溴代、异构化、羰基还原、环氧化、开环及脱保护7步反应以28.3%的总收率合成1α-羟基去氢表雄酮。该方法具有高效经济、技术可行、安全环保等优点,为1α-羟基去氢表雄酮的规模生产及维生素D类药物合成研究奠定理论基础。     

An efficient Fe(III)-catalyzed 1,6-conjugate addition of para-quinone methides with fluorinated silyl enol ethers toward β,β-diaryl α-fluorinated ketones

Reported here is a highly efficient 1,6-conjugate addition of fluorinated silyl enol ethers to para-quinone methides, allowing facile access to a range of β,β-diaryl α-fluorinated ketones with good to high yields. Fe(OTf)₃ was identified as the optimal catalyst, with the loading of 3?mol%. Notably, this represent the first 1,6-conjugate addition with fluorinated silyl enol ethers. The synthetic potential of the resulting adducts is also demonstrated.     

Facile preparation of ZrCO composite aerogel with high specific surface area and low thermal conductivity

A novel ZrCO composite aerogel is synthesized using zirconium oxychloride and resorcinol–formaldehyde (RF) as precursors through the sol–gel route and carbothermal reduction process. The effects of different Zr/R molar ratios and calcination temperatures on the physical chemistry properties of ZrCO aerogels are investigated. The ZrCO composite aerogel consists of the C/ZrO₂/ZrC ternary aerogel. The results show that with the increase of R/Zr molar ratios, the specific surface area and bulk density increase with calcination temperature up to 1300?°C, but decrease at even temperature (1500?°C). The specific surface area is as high as 637.4?m²/g for ZrCO composite aerogel (R:Zr?=?2:1), which was higher than ever reported. As the heat-treatment temperature increases to 1500?°C, the ZrC crystalline phase occurs and the t-ZrO₂ phase still appears within the composite. The thermal conductivity of the carbon fiber mat-reinforced composite aerogel is as low as 0.057?W/m/K at room temperature (25?°C).

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Introducing Fe2+ into Nickel–Iron Layered Double Hydroxide: Local Structure Modulated Water Oxidation Activity

Exploring materials with regulated local structures and understanding how the atomic motifs govern the reactivity and durability of catalysts are a critical challenge for designing advanced catalysts. Herein we report the tuning of the local atomic structure of nickel–iron layered double hydroxides (NiFe‐LDHs) by partially substituting Ni²⁺ with Fe²⁺ to introduce Fe‐O‐Fe moieties. These Fe²⁺‐containing NiFe‐LDHs exhibit enhanced oxygen evolution reaction (OER) activity with an ultralow overpotential of 195 mV at the current density of 10 mA cm^?2, which is among the best OER catalytic performance to date. In‐situ X‐ray absorption, Raman, and electrochemical analysis jointly reveal that the Fe‐O‐Fe motifs could stabilize high‐valent metal sites at low overpotentials, thereby enhancing the OER activity. These results reveal the importance of tuning the local atomic structure for designing high efficiency electrocatalysts.     

加速溶剂萃取/气相色谱-三重四极杆串联质谱法测定纺织品中24种多环芳烃

建立了加速溶剂萃取/气相色谱-三重四极杆串联质谱(ASE/GC-MS/MS)同时测定纺织品中24种多环芳烃(PAHs)的方法。样品经丙酮加速溶剂萃取,旋蒸浓缩后采用DB-35色谱柱程序升温分离,选择多反应监测模式(MRM)采集,外标法定量。结果表明,在一定浓度范围内多环芳烃的峰面积与质量浓度呈良好的线性关系,相关系数(r~2)均大于0.994,方法检出限为0.000 3~0.03 mg/kg,方法定量下限为0.001~0.10 mg/kg,加标回收率为80.3%~103%,相对标准偏差(RSD)为1.3%~9.2%。该方法灵敏、准确可靠,能满足纺织品中24种多环芳烃的测试要求。     

High-efficiency quaternary polymer solar cells enabled with binary fullerene additives to reduce nonfullerene acceptor optical band gap and improve carriers transport

The polymer/small-molecule electron donor and nonfullerene organic electron acceptor are of structural similarity with both donor and acceptor molecules consisting of polycyclic fused-ring backbone and being decorated with alkyl-chains.In this study,we report that the introduction of binary fullerenes(C_(60)-/C_(70)-PCBM and C_(60)-/C_(70)-ICBA)into a nonfullerene binary system PBDB-T:ITIC reduces the polymer-nonfullerene acceptor intermixing,obtaining higher crystallinity with(100)crystal coherence length from 28 to 29–33 nm for the ITIC,and from 14 to 20–24 nm for the PBDB-T,and improved electron and hole mobilities both.Unprecedentedly,such a protocol reduces the ITIC optical band gap from 1.59 to 1.55 eV.As consequences,higher short-circuit current-density(17.8–18.4 vs.15.8 m A/cm~2),open-circuit voltage(0.92 vs.0.90 V)and fill-factor(0.72–0.73 vs.0.68)are simultaneously obtained,which ultimately afford higher efficient quaternary polymer solar cells with power conversion efficiencies(PCEs)up to 12.0%–12.8%comparing to the host binary device with 9.9%efficiency.For the polymer,ITIC,and ICBA/PCBM ternary blends,11%PCEs were recorded.The use of PCBM leads to larger red-shifting in thin film absorption and external quantum efficiency(EQE)response.Such effect is more pronounced when ICBA:PCBM mixture is used.These results indicate the size and shape of C_(60)and C_(70)as well as the substituent position of the second indene unit on C_(60)-/C_(70)-ICBA affect not only the blend morphology but also the electronic coupling in BHJ mixtures:the quaternary device performance increased in sequences of C_(70)-PCBM:C_(70)-ICBA→C_(70)-PCBM:C_(60)-ICBA→C_(60)-PCBM:C_(70)-ICBA→C_(60)-PCBM:C_(60)-ICBA.The resonant soft X-ray scattering(RSoXS)data indicated the most refined phase separation in the C_(60)-PCBM:C_(60)-ICBA based blend,corresponding to its best device function among the quaternary devices.These results indicate that the using of binary fullerenes as the acceptor additives allows for tuning nonfullerene blended film’s optical properties and filmmorphologies,shedding light on the designing high-performance multi-acceptor polymer solar cells.     

Direct Observation of Transition Metal Dichalcogenides in Liquid with Scanning Tunneling Microscopy

We present atomic-resolution images of TiSe\begin{document}$_2$\end{document}, MoTe\begin{document}$_2$\end{document} and TaS\begin{document}$_2$\end{document} single crystals in liquid condition using our home-built scanning tunneling microscopy (STM). By facilely cleaving of single crystals in liquid, we were able to keep the fresh surface not oxidized within a few hours. Using the high-stable home-built STM, we have obtained atomic resolution images of TiSe\begin{document}$_2$\end{document} accompanied with the single atom defects as well as the triangle defects in solution for the first time. Besides, the superstructure of MoTe\begin{document}$_2$\end{document} and hexagonal charge-density wave domain structure in nearly commensurate phase of TaS\begin{document}$_2$\end{document} were also obtained at room temperature (295 K). Our results provide a more efficient method in investigating the lively surface of transition metal dichalcogenides. Besides, the high stable liquid-phase STM will support the further investigations in liquid-phase catalysis or electrochemistry.     

高三尖杉酯碱和三尖杉酯碱的合成研究

天然药物高三尖杉酯碱和三尖杉酯碱是从三尖杉植物的叶和茎中分离得到的微量生物碱,是手性化合物。结构上,二者不仅含有一个共同的母核三尖杉碱,酯基侧链的α位也均为手性叔醇。因母核三尖杉碱和酯基侧链较大的空间位阻,两个结构片段的酯化偶联具有较大的挑战性。设计合成位阻较小的侧链中间体是酯化反应发生的关键。因此,化学家们相继合成了结构多样的α-羰基羧酸侧链以及含有杂环的侧链中间体,如四元内酯杂环侧链、四氢呋喃杂环侧链、六氢吡喃杂环侧链、七元内酯杂环侧链,并成功地完成了高三尖杉酯碱、三尖杉酯碱和同属其他活性生物碱的合成。本文基于本课题组的相关研究,根据侧链片段的构建策略和方法,综述了天然药物高三尖杉酯碱、三尖杉酯碱以及其他天然产物的合成研究。不仅总结了近几年来的新进展,还对我国老一辈的科学家们在此方面作出的贡献进行了回顾。     

Uranyl ion adsorption studies on synthesized phosphoryl functionalised MWCNTs: a mechanistic approach

Nickel hydroxide solubility has been studied in this work in different cementitious systems. Our results indicate that once Glenium^® 27, cement superplasticizer admixture, is added to water and then mixed with cement, this polymeric material is stabilized and not released back to the aqueous solution, with negligible effects on the mobility of nickel. Contrary to that, when Glenium^® 27 is added directly in solution at high dosages, an important effect is observed on nickel behaviour. Thermodynamic calculations indicate that the effect of such component on Ni is likely the effect that other small organics could have over this element.