Novel Zn（Ⅱ） ladder-like coordination polymer constructed from designed ferrocenyl ligand

Reaction of Zn（NO3）2·6H2O with 3-（4-carboxylphenylamino）-l-ferrocenyl-2-butylen-l-one （HL） and 4,4′-bipyfidine （4,4′- bipy） in methanol solution resulted in a novel ladder-like coordination polymer {[Zn2L2（μ2-L）2（4,4′-bipy）2]·MeOH}n （1）. Its crystal structure, thermal and electrochemical properties are presented.     

A new cytotoxic 2-（2-phenylethyl）chromone from Chinese eaglewood

A new compound 8-chloro-5,6,7-trihydroxy-2-（3-hydroxy-4-methoxyphenethyl）-5,6,7,8-tetralaydro-4H-chromen-4-one （1） was isolated from the Chinese eaglewood [Aquilaria sinensis （Lour.） Gilg]. Its structure was elucidated on the basis of spectral data. Compound I showed cytotoxicity against human gastric cancer cell line （SGC-7901） in vitro by MTT method with the IC50 value of 14.6 μg/mL.     

立体选择性合成2-(a-噻吩甲酰基)-3-取代苯基-4-乙氧羰基-5-甲基-反式-2,3-二氢呋喃

溴化(a-噻吩甲酰基)甲基三苯鉮1与3-取代苯甲叉基-2,4-戊二酮 2以碳酸钾为碱,在苯中55℃条件下反应,可以较好的收率、高立体选择性地生成反-2-(a-噻吩甲酰基)-3-取代苯基-4-乙氧羰基-5-甲基-2,3-二氢呋喃3。产物结构均经波谱予以确定。本文还提出了生成产物的可能机理。     

氢过碘酸）合银（III）配离子氧化L-脯氨酸的反应动力学及机理

L-脯氨酸独有的亚胺基使其在生物医药领域具有许多独特的功能,并广泛用作不对称有机化合物合成的有效催化剂。本文在碱性介质中研究了二（氢过碘酸）合银（III）配离子氧化 L-脯氨酸的反应。经质谱鉴定,脯氨酸氧化后的产物为脯氨酸脱羧生成的 γ-氨基丁酸盐;氧化反应对脯氨酸及Ag(III) 均为一级;二级速率常数 k′ 随 [IO₄^-] 浓度增加而减小,而与 [OHˉ] 的浓度几乎无关;推测反应机理应包括 [Ag(HIO₆)₂]^5-与 [Ag(HIO₆)(H₂O)(OH)]^2-之间的前期平衡,两种Ag（III）配离子均作为反应的活性组分,在速控步被完全去质子化的脯氨酸平行地还原,两速控步对应的活化参数为： k₁ (25 ^oC)＝1.87±0.04（mol·L^-1)^-1s^-1,∆ H₁^≠＝45±4 kJ · mol^-1, ∆ S₁^≠＝-90±13 J· K^-1·mol^-1 and k₂ (25 ^oC) ＝3.2±0.5（mol·L^-1)^-1s^-1, ∆ H₂^≠＝34±2 kJ · mol^-1, ∆ S₂^≠＝-122 ±10 J· K^-1·mol^-1。本文第一次发现 [Ag(HIO₆)₂]^5-配离子也具有氧化反应活性。     

A new anthraquinone glycoside from seeds of Cassia obtusifolia

A new anthraquinone glycoside 1, along with a known anthraquinone glycoside aurantio-obmsin-6-O-β-D-glucopyranoside 2, were isolated from the seeds of Cassia obtusifolia. On the basis of spectral and chemical evidences, the structure of 1 was established as 1-demethylaurantio-obtusin-2-O-β-D-glucopyranoside. Moreover, the 13C NMR of 2 was assigned totally and correctly for the first time based on the two-dimensional NMR.     

Glucose, cellobiose, lactose and raffinose used as chiral stationary phases in HPLC

This paper presents the enantioseparation using glucose, cellobiose, lactose and raffinose as chiral selector bonded to silica gel via an arm in HPLC. Surprisingly, they also possess high enantioseparation selectivity, may be used in normal-phase and reversed- phase mode, and there is a big chiral discriminating complementary. This work indicates that oligosaccharides could soon become very attractive as a new class of chiral stationary phase for HPLC.     

Improved Electrocatalytic Activity and Stability by Single Iridium Atoms on Iron-based Layered Double Hydroxides for Oxygen Evolution

Full understanding to the origin of the catalytic performance of a supported nanocatalyst from the points of view of both the active component and support is significant for the achievement of high performance. Herein, based on a model electrocatalyst of single-iridium-atom-doped iron (Fe)-based layered double hydroxides (LDH) for oxygen evolution reaction (OER), we reveal the first completed origin of the catalytic performance of such supported nanocatalysts. Specially, besides the activity enhancement of Ir sites by LDH support, the stability of surface Fe sites is enhanced by doped Ir sites: DFT calculation shows that the Ir sites can reduce the activity and enhance the stability of the nearby Fe sites; while further finite element simulations indicate, the stability enhancement of distant Fe sites could be attributed to the much low concentration of OER reactant (hydroxyl ions, OH⁻) around them induced by the much fast consumption of OH⁻ on highly active Ir sites. These new findings about the interaction between the main active components and supports are applicable in principle to other heterogeneous nanocatalysts and provide a completed understanding to the catalytic performance of heterogeneous nanocatalysts.     

The Universal Super Cation-Conductivity in Multiple-cation Mixed Chloride Solid-State Electrolytes

As exciting candidates for next-generation energy storage, all-solid-state lithium batteries (ASSLBs) are highly dependent on advanced solid-state electrolytes (SSEs). Here, using cost-effective LaCl₃ and CeCl₃ lattice (UCl₃-type structure) as the host and further combined with a multiple-cation mixed strategy, we report a series of UCl₃-type SSEs with high room-temperature ionic conductivities over 10⁻³ S cm⁻¹ and good compatibility with high-voltage oxide cathodes. The intrinsic large-size hexagonal one-dimensional channels and highly disordered amorphous phase induced by multi-metal cation species are believed to trigger fast multiple ionic conductions of Li⁺, Na⁺, K⁺, Cu⁺, and Ag⁺. The UCl₃-type SSEs enable a stable prototype ASSLB capable of over 3000 cycles and high reversibility at −30 °C. Further exploration of the brand-new multiple-cation mixed chlorides is likely to lead to the development of advanced halide SSEs suitable for ASSLBs with high energy density.     

金银合金纳米粒子表面处理及其表面增强拉曼光谱研究

采用水合肼还原的方法制备了金银比例为1∶1的金银合金纳米粒子, 紫外可见吸收光谱显示合成的溶胶只有一个介于金和银之间的吸收峰, 证明了合金结构的形成. 通过氨基耦联方法将合金纳米粒子组装到硅片表面, 利用氯金酸与合金中银的反应对基底上合金纳米粒子表面进行了改性处理. 以吡啶为探针分子, 研究了表面处理前后基底的SERS效应的差别, 结果表明随着浸泡时间延长, 信号强度先逐渐增强后降低至不变, 这与合金纳米粒子表面结构的变化有关, 氯金酸与表面银的反应经历了两个过程, 即粒子表面形成小的孔洞(去合金过程)和AgCl(s)在粒子表面的沉积, 前者有利于SERS效应的提高, 而后者导致SERS效应快速衰减.     

The study on the preparation methods and the fluidity of large rare earth oxide particles

In this work large CeO₂ particles were prepared using H₂C₂O₄ and NH₄HCO₃ as precipitators. The effects of feeding mode and speed, stirring speed, aging time, precipitate and calcination temperature and precipitation method on physicochemical properties of CeO₂ were studied when the precipitator was H₂C₂O₄. By the NH₄HCO₃ precipitation method, the effects of adding inoculating crystals and additives on particle size, loose density and fluidity of CeO₂ were investigated. Under optimized conditions, large CeO₂ particles with high loose density and good fluidity of can be prepared by either H₂C₂O₄ or NH₄HCO₃ precipitation method. SEM also investigates the morphology of the particles prepared by both methods. The results show that physicochemical properties of CeO₂ particles prepared by the NH₄HCO₃ precipitation method are not as good as those of CeO₂ particles prepared by the H₂C₂O₄ precipitation method. However, both methods are suitable for industrial production due to their simple processes, low equipment investment and ease for industrial development. Our results show that large rare earth particle can be prepared by the optimized conventional methods. This study provided a useful method to prepare of large rare earth particles.