Synthesis of 2-indanones via [4 + 1] annulation reactions of (trialkylsilyl)arylketenes

[reaction: see text] (Trialkylsilyl)arylketenes combine with (trimethylsilyl)diazomethane in a new [4 + 1] annulation process leading to 2-indanone derivatives. The (trialkylsilyl)arylketene annulation substrates are available via the photochemical Wolff rearrangement of alpha-silyl-alpha-diazo ketones, which are themselves prepared by silylation of the corresponding diazo ketones. The mechanism of the annulation reaction is proposed to involve the formation of a 2,3-bis(silyl)cyclopropanone, which is in equilibrium with an oxyallylic cation. Electrocyclic closure of this intermediate forms the new cyclopentenone ring.     

基于无结构网格单元中心有限体积法的二维对流扩散方程离散

在无结构网格单元中心有限体积法二维水流模型基础上,建立物质输运对流扩散方程离散模式.通过通量重构法和SOM(Support Operators Method),分别对输运方程的对流项和扩散项进行离散.该离散模式具有空间二阶精度,并适用于任意多边形无结构网格.通过纯对流和纯扩散算例对模型进行检验和验证,结果表明,模型能够较好地模拟物质输运的对流扩散问题.应用模型模拟瓯江河口的盐度输运,通过计算值与实测值对比,进一步检验模型.     

Concept Design,Development and Preliminary Physical and Chemical Characterization of Tamoxifen-Guided-Mesoporous Silica Nanoparticles

Conventional chemotherapies used for breast cancer (BC) treatment are non-selective, attacking both healthy and cancerous cells. Therefore, new technologies that enhance drug efficacy and ameliorate the off-target toxic effects exhibited by currently used anticancer drugs are urgently needed. Here we report the design and synthesis of novel mesoporous silica nanoparticles (MSNs) equipped with the hormonal drug tamoxifen (TAM) to facilitate guidance towards estrogen receptors (ERs) which are upregulated in breast tumours. TAM is linked to the MSNs using a poly-ʟ-histidine (PLH) polymer as a pH-sensitive gatekeeper, to ensure efficient delivery of encapsulated materials within the pores. XRD, HR-TEM, DLS, SEM, FT-IR and BET techniques were used to confirm the successful fabrication of MSNs. The MSNs have a high surface area (>1000 m²/g); and a mean particle size of 150 nm, which is an appropriate size to allow the penetration of premature blood vessels surrounding breast tumours. Successful surface functionalization was supported by FT-IR, XPS and TGA techniques, with a grafting ratio of approximately 29%. The outcomes of this preliminary work could be used as practical building blocks towards future formulations.     

Application of Graphdiyne and Its Analogues in Photocatalysis and Photoelectrochemistry

Graphdiyne(GDY),a new carbon allotrope composed of sp-sp2 carbon atoms,has attracted increased attention in recent years.It has a direct band gap of 0.46-1.22 eV,high charge carrier mobility and lower work function compared to most of the typical semiconductors,which ensure successful hybridization with other semiconductors(e.g.,TiO2,g-C3N4).This review aims at discussing recent achievements of GDY and its analogues applied in photocatalytic and photoelectrochemical(PEC)reactions.Meanwhile,some challenges and new perspectives of opportunities in developing catalysts and electrodes based on GDY and its analogues are also discussed.     

Large Two‐Photon Absorption of Terpyridine‐Based Quadrupolar Derivatives: Towards their Applications in Optical Limiting and Biological Imaging

Developing organic chromophores with large two‐photon absorption (TPA) in both organic solvents and aqueous media is crucial owing to their applications in solid‐state photonic devices and biological imaging. Herein, a series of novel terpyridine‐based quadrupolar derivatives have been synthesized. The influences of electron‐donating group, type of conjugated bridge, as well as solvent polarity on the molecular TPA properties have been investigated in detail. In contrast to the case in organic solvents, bis(thienyl)‐benzothiadiazole as a rigid conjugated bridge will completely quench molecular two‐photon emission in aqueous media. However, the combination of alkylcarbazole as the donor and bis(styryl)benzene as a conjugation bridge can enlarge molecular TPA cross‐sections in both organic solvent and aqueous media. The reasonable two‐photon emission brightness for the organic nanoparticles of chromophores 3 – 5 in the aqueous media, prepared by the reprecipitation method, enables them to be used as probes for in vivo biological imaging.     

Production of 62Zn radioactive nuclear beam and on-line PAC investigation of quadrupole interaction in nano-magnetic material Fe73.5Cu1Nb3Si13.5B9

An Isotope Separator On-Line (ISOL), dedicated to on-line perturbed angular correlation (PAC) and positron annihilation spectroscopy (PAS), has been constructed at CIAE based on the HI-13 tandem accelerator, and a 30 keV radioactive beam of ⁶²Zn with intensity of 2 ×10⁷/s produced by it. Using the ⁶²Zn radioactive beam the investigation of the nano-crystalline soft magnetic Fe_73.5Cu₁Nb₃Si_13.5B₉ materials has been fulfiled for the first time by the on-line time differential PAC technique. Two quadrupole interaction frequencies ω ₀₁ (?=?440 Mrad/s) and ω ₀₂ (?=?90 Mrad/s) were gained, indicating there are two implantation sites of ⁶²Zn. The frequency ω ₀₂ shows a fluctuation of the crystal lattice constants and proves the characteristic distribution model of nano-crystalline grain boundary. The frequency ω ₀₁ demonstrates that the implanted ⁶²Zn occupies the site of the ordered grain core. The fractions of ω ₀₁ and ω ₀₂ are f₀₁?=?38 % and f₀₂?=?62 %, respectively.     

Inner‐sphere reorganization for redox pairs M(NH3)62+/3+ (M=Mn,Fe, and Co): Models and calculations

The inner‐shell reorganization and activation models of the electron‐transfer reactions of transition‐metal hexammine complexes are presented. The inner‐shell reorganization and activation energies of several hexammine redox pairs M(NH₃)₆^2+/3+ (M=Mn, Fe, and Co) in self‐exchange reactions are studied by different formalisms. The extent of the anharmonicities in the vibration between the metal–ion and the ligands in the reorganization process of these complexes is determined. The inner‐shell barriers of these redox pairs are dependent on reorganization model used. The contribution of the individual reactants to the inner‐shell barrier is sensitive to the model used. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001     

耐超高温双酮酐型聚酰亚胺的合成及性能

以4,4'-对苯二甲酰二邻苯二甲酸酐(TDPA)为芳二酐单体,对苯二胺(PPD)为芳二胺单体,经低温溶液缩聚制得成膜性能优良的高相对分子质量聚酰胺酸(PAA),再经过热亚胺化制备双酮酐型聚酰亚胺(PI)薄膜。 采用傅里叶变换红外光谱仪(FT-IR)、广角X射线衍射(WAXD)、差示扫描量热仪(DSC)、动态热机械分析仪(DMA)、热重分析仪(TGA)、紫外-可见分光光度计(UV-Vis)及力学性能等技术手段表征了聚酰亚胺膜的结构和性能,考察了不同亚胺化温度对合成的双酮酐型聚酰亚胺膜性能的影响。 结果表明,经程序升温至320 ℃能使PAA热亚胺化基本趋于完成。 PI薄膜为部分有序聚集态结构,玻璃化转变温度(T_g)为298 ℃,具有优异的热性能,热失重温度(T_5%)为523 ℃。 拉伸强度达到130 MPa,弹性模量为5.77 GPa。 PI薄膜紫外光透过截止波长为375 nm,在可见光区具有良好的透光性能及耐溶剂性能。