Delayed Fluorescent Emission from Pyrene Doped Phenanthrene Nanoparticles Based on Triplet-triplet Energy Transfer

Doped nanoparticles were prepared from pyrene and phenanthrene using a facile reprecipitation method. The doped nanoparticles presented unique delayed fluorescent emissions of pyrene under the unprotected condition. The ratio of the intensity of delayed fluorescence (I_DF) to that of phosphorescence (I_P) is about 4:1, which almost keeps unchanged with the decrease of pyrene content at room temperature. The intensity of the delayed fluorescence emissions is dependent on the relative content of pyrene, as well as the aggregation degree of nanoparticles. The delayed emissions are contributed to efficient triplet‐triplet energy transfer from phenanthrene (donor) to pyrene (acceptor). Steady fluorescence measurement have proved that the singlet‐singlet energy transfer process was also existent dominated by the radiation energy transfer mechanism.     

Synthesis and Structural Characterization of Lanthanide Amides Stabilized by an N-Aryloxo Functionalized β-Ketoiminate Ligand

The synthesis and characterization of dimeric lanthanide amides stabilized by a dianionic N‐aryloxo functionalized β‐ketoiminate ligand are described in this paper. Reactions of 4‐(2‐hydroxy‐5‐tert‐butyl‐phenyl)imino‐2‐pentanone (LH₂) with Ln[N(SiMe₃)₂]₃(µ‐Cl)Li(THF)₃ in a 1:1 molar ratio in THF gave the dimeric lanthanide amido complexes [LLn{N(SiMe₃)₂}(THF)]₂ [Ln=Nd ( 1 ), Sm ( 2 ), Yb ( 3 ), Y ( 4 )] in good isolated yields. These complexes were characterized by IR spectroscopy, elemental analysis, and ¹H NMR spectroscopy in the case of complex 4 . The definitive molecular structures of complexes 1 , 3 , and 4 were determined. It was found that complexes 1 to 4 can initiate the ring‐opening polymerization of L‐lactide.     

A new shortcut synthesis route for (±)raphidecursinol

<正>The new shortcut synthesis route of(±)raphidecursinol 1,a racemic 8,4′-oxyneolignan compound,can be more easily achieved by the synthesis route,starting from readily available inexpensive 3,4,5-trimethoxybenzaldehyde and 1,2,3-trihydroxybenzene.All structures were confirmed by ~1H NMR,IR and MS.     

Synthesis and CDK2 kinase inhibitory activity of 7/7′-azaindirubin derivatives

A series of novel 7′-azaindirubin (1a-g) and 7-azaindirubin (2a, 2c, 2e and 2f) derivatives were designed and synthesized. Their structures were characterized by 1H NMR and MS spectroscopy as well as by elemental analysis. Their inhibitory properties against CDK2/cylinA were evaluated in vitro. In contrast to indirubin, some of the described azaindirubins emerged as potent inhibitors of CDK2/cylinA and compound 2b had more potent activity. Biological tests also showed that nitrogen atom at 7-position of azaindirubin was more beneficial to enhance the kinase inhibitory activity.     

Separation of gibberellin A4 from A4 and A7 mixture by selective complex

<正>Gibberellin A4 is effectively separated from mixture of gibberellin A4 and its analogue gibberellin A7,in the form of its crystalline complex with N,N,N',N'-tetramethylethylenediamine.After removing the tetramethylethylenediamine from the crystal by dilute HCl,gibberellin A4 is obtained a purity of 98.1%and a yield of 72.7%.     

The detection of tetrahydrofuran hydrate formation and saturation using magnetic resonance imaging technique

Tetrahydrofuran (THF) hydrate was formed in bulk as well as in glass beads pack with a mean diameter of 3.0 mm by controlling the temperature under ambient pressure. Images of THF hydrate formation procedure were obtained using the magnetic resonance imaging (MRI) technique. The experiment results showed that MRI is an effective method for the detection of hydrate formation. Saturation of hydrate formed both in bulk and glass beads can be confirmed by intensity integration of MRI images.     

Studies on mono- and dinuclear bisoxime copper complexes with different coordination geometries

Two new mono- and dinuclear Cu(II) complexes, namely [CuL¹]·0.5H₂O (1) and [(Cu₂(L²)₂)(DMF)]·0.5DMF (2) (H₂L¹ = 1,2-bis{[(Z)-(3-methyl-5-oxo-1-phenyl-1H-pyrazolidin-4(4H)-yl)(phenyl)]methylene-aminooxy}ethane; H₂L² = 1,3-bis{[(Z)-(3-methyl-5-oxo-1-phenyl-1H-pyrazolidin-4(4H)-yl)(phenyl)] methyleneaminooxy}propane), have been synthesized and characterized by X-ray crystallography. The unit cell of complex 1 contains two crystallographically independent but chemically identical [CuL¹] molecules and one crystalline water molecule, showing a slightly distorted square-planar coordination geometry and forming a wave-like pattern running along the a-axis via hydrogen bonding and π···π stacking interactions. Complex 2 has a dinuclear structure, comprising two Cu(II) atoms, two completely deprotonated phenolate bisoxime (L²)²⁻ moieties (in the form of enol), and both coordinated and hemi-crystalline DMF molecules. Complex 2 has square-planar and square-pyramidal geometries around the two copper centers, whose basic coordination planes are almost perpendicular and form an infinite three-dimensional supramolecular network structure involving intermolecular C–H···N, C–H···O, and C–H···π(Ph) hydrogen bonding and π···π stacking interactions of neighboring pyrazole rings.     

比较研究山姜素和豆蔻明与人-γ球蛋白的相互作用

将互为同分异构体的两种植物药活性组分山姜素和豆蔻明作为研究对象,应用荧光光谱法、紫外光谱法以及红外光谱法并结合分子对接技术首次对这两种黄酮类化合物与人-γ球蛋白(Human gammagobulin,HG)的相互作用进行了详细研究.荧光光谱法的研究结果表明,这两种药物均与HG有较强的相互作用(结合常数均在104～105之间);山姜素对HG表现为静态猝灭机理,而豆蔻明对HG表现出非常少见的动态猝灭机理.比较不同温度(298,308和318K)下两种药物与蛋白相互作用的结合参数都有所差别,维持药物-HG体系的作用力也不同.山姜素和豆蔻明分子与HG色氨酸残基间的结合距离r值(分别为3.88和4.52nm)都小于7nm,说明发生了能量转移.同步荧光与红外光谱法定性及定量地研究了药物对HG二级结构的不同影响程度.两种分子对接结果表明了这两种药物与HG的结合区域.     

KI与无机铵盐催化CO2与环氧丙烷合成碳酸丙烯酯

以无毒、合成简单、廉价的无机铵盐(氨基甲酸铵、碳酸氢铵、碳酸铵等)为助催化剂,研究其对卤化钾(KCl、KBr、KI)催化CO2与环氧丙烷合成碳酸丙烯酯(PC)的影响.结果表明,卤化钾与无机铵盐显示出很好的协同催化效应.其中以氨基甲酸铵为助催化剂,KI为主催化剂时,催化合成PC的效果最好.同时考察了催化剂用量、反应温度、CO2初始压力、PC的预加入量、反应时间等因素对反应的影响.在优化条件下,PC收率大于99%.     

4-巯乙基吡啶配基与IgG相互作用的分子模拟研究

4-巯乙基吡啶(MEP)是一种新型的疏水性电荷诱导层析(HCIC)配基,具有良好的抗体分离性能,采用分子模拟方法研究MEP配基与IgG间的分子相互作用,以探讨HCIC分离机制.先通过分子对接搜索IgG分子Fc片段A链的蛋白表面,确定12个可能与MEP结合的位点区域,然后用分子动力学模拟考察了其中6个位点的结合性能.结果表明,MEP在Fc-A链表面的结合具有疏水倾向性,pH中性条件下,MEP能稳定地结合在TYR319和LEU309附近的位点,并与两者形成氢键作用,该区域具有疏水性极强的口袋结构;其他位点的结合较不稳定,受MEP取向影响大.在pH4.0酸性条件下,原先稳定结合的MEP快速从Fc-A链表面脱离,主要原因是MEP和Fc间的静电排斥作用,以及疏水作用减弱和氢键结合的消失.通过分子模拟方法,从分子水平验证了HCIC独特的作用机理:疏水相互作用主导吸附,静电排斥作用协助解吸.