The ring-opening of chiral oxazoline involving pyrrolidone

Chiral N-[1-benzyl-2-hydroxyethyl]-3-[2-oxo-pyrrole]propionamide (C₁₆H₂₂N₂O₃) was obtained unexpectedly from the reaction of oxazoline involving pyrrolidone with copper acetate monohydrate, and the structure was characterized by NMR, IR, elemental analysis, and X-ray analysis.     

CCQM-K74国际比对中二氧化氮浓度的测量

介绍了国际比对样品中10μmol/mol NO2气体浓度精确分析方法的建立过程。该方法的建立包括标准物质的制备、分析仪器的选择和测量结果的不确定度3个主要的方面。标准物质的制备及其量值的不确定度评价采用了气体标准物质定值的基准方法——称量法。对傅立叶变换红外光谱法(FTIR)和化学发光光谱法进行了比较研究。确定了更适合于本次国际比对样品的分析方法为化学发光光谱法,测量结果的相对扩展不确定度为1.0%(k=2)。本次比对的最终结果报告显示,所建立的分析方法准确可靠。     

高质量NaNdF4六方棱柱纳米棒的水热形貌控制合成及发光性质

采用水热法在温和的条件下合成了具有规则外形的六方棱柱状NaNdF₄纳米棒。X射线衍射（XRD）分析表明：产物为纯六方相NaNdF₄,场发射扫描电镜（SEM）分析表明产物形貌为棱柱状纳米棒,长约为550nm,棒的端部呈规则六边形,边长约为85nm。高分辨透射电子显微镜（HRTEM）和选区电子衍射（SD）显示所得样品为良好的单晶。NaNdF₄晶体的生长动力学过程表明：螯合剂（EDTA-Na₂）与稀土金属离子间的螯合作用受pH值影响,导致成核速度变化,进而影响NaNdF₄纳米晶的最终尺寸和形貌。室温下的NaNdF₄纳米棒的发光峰位于红外光范围（λ=892,1058,和1342nm）,其最强发射峰位于1058nm,对应于Nd³⁺的⁴F_3/2→⁴I_11/2f-f跃迁。     

A copper-based coordination polymer formed through synergistic bridging of 1,2,4-triazole and acetate anions: synthesis,crystal structure and magnetic properties

Transition Metal Chemistry - A Cu(II) coordination polymer, [Cu2(pztrz)2(μ-CH3COO)(CH3COO)]·3H2O (1), derived from mono-substituted 1,2,4-triazole derivative 3-(pyrazinyl)-1,2,4-triazole...     

Crystal phase control in two-dimensional materials

It is the nature of crystals to exist in different polymorphs. The recent emergence of two-dimensional (2D) materials has evoked the discovery of a number of new crystal phases that are different from their bulk structures at ambient conditions, and revealed novel structure-dependent properties, which deserve in-depth understanding and further exploration. In this contribution, we review the recent development of crystal phase control in 2D materials, including group V and VI. transition metal dichalcogenides (TMDs), group IVA metal chalcogenides and noble metals. For each group of materials, we begin with introducing the various existing crystal phases and their structure-related properties, followed by a detailed discussion on factors that influence these crystal structures and thus the possible strategies for phase control. Finally, after summarizing the whole paper, we present the challenges and opportunities in this research direction.     

四苯硼阴离子电子结构的理论研究

分别应用半经验发子轨道理论的AM1方法和在HF／3－21G水平上的从头算分子轨道法,对四苯硼阴离子的电子结构进行了研究。采用解析梯度技术对四苯硼阴离子的平衡态几何构型进行了全优化,得到了分子轨道、电荷布居、静电势以及红外光谱和紫外光谱等参数,计算结果表明：四苯硼阴离子的静电势分布均匀,其前线轨道能级间隔为12．1398eV,利用组态相互作用法得到的紫外光谱跃迁吸收峰主要位于远紫外区,说明四苯硼离子比较稳定,从头算法得到的红外光谱吸收峰分布与实验结果一致,AM1法得到的红外吸收频率与实验值更接近。     

超疏水多孔阵列碳纳米管薄膜

碳纳米管由于具有特异的力学[1] 、光学[2 ] 、电学[3,4 ] 和磁学性质[5] ,使其在锂离子电池[6 ] 和平板展示器[7] 等方面呈现出广泛的应用前景 .Ebbesen等[8] 对无序碳纳米管材料的浸润性进行了详细研究 ,发现其很容易被水润湿 .然而 ,阵列碳纳米管膜的浸润性研究尚未见报道 .固体表面的浸润性主要由表面化学组分和几何结构两方面控制 .通常 ,加大表面粗糙度可以增强其浸润性 [9～ 16 ] .近来 ,超疏水表面 (即与水的接触角大于 1 5 0°的表面 )的研究显示了广泛的应用背景[13～ 16 ] .这种表面通常可由增加表面粗糙度和降低表面能来制备[1…     

Host–guest‐like thi­amine–anion complexation in thia­minium bis­(tetra­fluoro­borate)

In the title compound, 3‐[(4‐amino‐2‐methyl‐5‐pyrimidin‐1‐io)methyl]‐5‐(2‐hydroxy­ethyl)‐4‐methyl­thia­zolium(2+) bis(tetra­fluoro­borate), C₁₂H₁₈N₄OS²⁺·2BF₄^?, the divalent thia­mine cation (in the F conformation) is associated with BF₄^? anions via two characteristic bridging interactions between the thia­zolium and pyrimidinium rings, i.e. C—H?BF₄^??pyrimidinium and N—H?BF₄^??thia­zolium interactions. Thi­amine mol­ecules are linked by N—H?O hydrogen bonds to form a helical chain structure.     

Synthesis and biological evaluation of a lipopeptide-based methamphetamine vaccine

We describe an application of carrier protein-free strategy in constructing a fully synthetic methamphetamine (METH) vaccine that contains three components: Toll-like receptor 2 ligand, Th2 epitope, and METH hapten. The immunological evaluation in mice revealed high titers of METH-specific antibodies induced by the construct and the activation of humoral immunity that would be beneficial for neutralization and clearance of the METH molecule. Behavioral experiments indicated that the synthetic vaccine attenuated the acquisition of METH-induced conditioned place preference and inhibited the initiation and expression of METH-induced locomotor sensitization. These results demonstrate that the lipopeptide-based vaccine has invoked an immune response and showed the potential of preventing the rewarding and psychoactive effects of METH.     

Two new cycloartanes from the leaves of Combretum quadrangulare growing in Vietnam and their biological activities

Two new cycloartanes, combretanones G and H (1 and 2), were isolated from the leaves of Combretum quadrangulare. Their structures were elucidated by applying a set of spectroscopic methods, while their relative configurations were determined using DFT-NMR chemical shift calculations and subsequent assignment of DP4 probabilities. Compounds 1 and 2 are C-23/C-24 stereoisomers of the previously-reported euphonerin E. Both exhibited moderate cytotoxicity against three human cancer cell lines. Compound 2 was shown to be a potent antiparasitic. Our results confirm the traditional medicinal uses of Combretum quadrangulare in Vietnam.