Halonickel 2,4-di-t-butyl-6-(quinolin-8-yliminomethyl)phenolates: Synthesis, characterization and ethylene reactivity

A series of nickel halides bearing 2,4-di-t-butyl-6-(quinolin-8-yliminomethyl) phenolate ligands was synthesized and characterized by IR spectroscopy and elemental analysis.Molecular structures of C1(R = H,X = Br) and C2(R = H,X = Cl) were further confirmed by single-crystal X-ray crystallographic studies,and revealed a distorted square planar geometry at nickel.Upon activation with diethylaluminum chloride(Et 2 AlCl),all nickel pre-catalysts displayed good catalytic activity [up to 9.3 × 10 5 g mol 1(Ni) h 1 ] for ethylene oligomerization with major dimerization.In the presence of methylaluminoxane(MAO),the nickel complex C1 was capable of ethylene polymerization under 3 MPa,and produced polyethylene products with narrow polydispersity(1.16 1.73) and molecular weights in the range of 2.6 4.95 kg/mol.     

An electrochemically prepared sky-blue light emitting ether functionalized polyfluorene as chemosensor for metal ions

Synthesis and electrochemical polymerization of 9,9-bis(2-(2-(2-methoxy ethoxy)ethoxy)ethyl)-fluorene(EO-F)into poly[9,9-bis(2-(2-(2-methoxy ethoxy)ethoxy)ethyl)-fluorene](EO-PF) films are reported. The boron trifluoride diethyl etherate electrolyte enables facile preparation of EO-PF films at lower potential compared to LiClO4/MeCN and the electrochemical polymerizations are discussed. The EO-PF shows good electrochemical behavior and can be dissolved in solvents such as DMSO and THF. The solubility of EO-PF in THF is 2 mg mL 1and the number average molecular weight is35300 with a polydispersity index of 1.65. The side chains on C9position of the monomer maintain unchanged after electrooxidation into corresponding polymer. The EO-PF dissolved in THF under 365 nm ultraviolet light is sky blue light emitting with the Commission Internationale de L Eclairage-CIE coordinates of(0.19, 0.15). The electropolymerized EO-PF is used for the first time in chemosensing metal ions, demonstrating fluorescence quenching for Mn2+and Fe3+while fluorescence enhancement for Cr6+ions.     

Synthesis, properties and electropolymerization of starshaped oligothiophenes with hexakis(fluoren-2-yl)benzene as core

Star-shaped oligothiophenes with hexakis(fluoren-2-yl)benzene (HFB) as cores were designed and synthesized. Grafting thiophene units to HFB results in a bond flattening of the core, and makes the molecules a flipping-twist shape. Their thermal, photophysical and electrochemical properties were studied. Highly cross-linked conjugated polymers can be produced by electropolymerization of T1-T3.     

A quick and green ionic liquid-mediated approach for the synthesis of high-performance, organosoluble and thermally stable polyimides

Three diamine monomers with different derivatives of imidazole heterocyclic ring and meta-linked aryl ethers were synthesized and used in polycodensation reaction with various commercial dianhydrides for preparation of a series of novel poly(ether-imide) (PEI)s. The polycodensation reactions were carried out by using conventional method and in a green medium of ionic liquid (IL) without using NMP-pyridine-acetic anhydride. The PEIs were obtained in good yields (80% 96%) with moderate viscosity (0.48 0.66 dL/g) in a shorter reaction time (10 h) in IL as compared with the conventional method (36 h). All of the polymers were amorphous in nature, showed excellent solubility in amide-type polar aprotic solvents with ability to form tough and flexible films, and excellent thermal stability with Tgs in the range of 212 340 ℃ and 10% weight loss temperature (T10) up to 570℃ in N 2 and 528 ℃ in air.     

近红外光谱结合化学计量学评价胚胎发育潜能

使用近红外光谱分析方法测量培养后的胚胎培养液,结合偏最小二乘判别分析对胚胎发育潜能进行评价,鉴别具有妊娠能力与不具妊娠能力的胚胎。为了提高模型的判别能力,消除无信息变量对模型稳定性影响,分别采用基于蒙特卡罗的无信息变量消除法(MC-UVE)、竞争性自适应加权抽样法(CARS)与基于变量稳定性的竞争性自适应加权抽样法(SCARS),对光谱进行波长选择。结果表明,与采用全谱74%的正判率相比较,采用这3种波长选择方法,模型独立检验集的正判率分别提高至74.24%,77.12%与80.10%,建模使用变量数降至50以内。比较发现,SCARS的模型优化能力和稳定性均好于MC-UVE和CARS方法。采用近红外光谱结合化学计量学方法预测胚胎的发育潜能是可行的。     

埃罗替尼的合成

以N,N-二甲基甲酰胺和硫酸二甲酯反应生成的亚胺盐与3-乙炔基苯胺进行亲核反应及甲醇的消去,获得了制备埃罗替尼所需的重要中间体N’-(3-乙炔基苯基)-N,N-二甲基甲脒,收率为75.8%。再以此中间体与2-氨基-4,5-二(2-甲氧基乙氧基)苯甲腈通过Dimroth重排反应方便地制得了抗肿瘤药物埃罗替尼,总收率(以3-乙炔基苯胺计)为56.5%。与以往合成埃罗替尼的方法相比,该方法更经济、更绿色。     

氧化偶联策略在复杂吲哚生物碱全合成中的应用

氧化偶联反应作为一种高效、经济的C—C键构建策略,在天然产物的全合成中得到了重要的应用.近年来,马大为课题组通过发展高效的LiHMDS/I2偶联条件,成功实现了四种复杂吲哚生物碱的全合成,在该领域取得了重要的进展.本文就马大为课题组近年在该领域的工作作一亮点评述.     

Mannich反应合成3,6(8)-二取代-2,4-二氢-1,3-苯并(口恶)嗪及其杀菌活性

以取代苯酚、多聚甲醛和取代苯胺为原料,在无催化剂的条件下,通过Mannich缩合反应合成了一系列新型3,6(8)-二取代-2,4-二氢-1,3-苯并(口恶)嗪类化合物.结果表明,取代苯酚和取代苯胺的取代基为供电子基时,合成产物的产率高于吸电子取代基的.产物的结构用1H NMR、13C NMR、IR和MS等进行了表征.初步测试了目标化合物的杀菌活性,部分化合物具有较好的杀菌活性.当浓度为25 mg/L时,化合物4j和4d对菌核病菌的抑制率分别为86.1％和81.5％,化合物4i对灰霉病菌的抑制率为81.6％.     

双酚A在壳聚糖石墨烯复合膜电化学传感器上的电化学行为及测定

采用hummers法制备了石墨烯,以碳糊电极为基底电极采用滴涂法制备了壳聚糖石墨烯复合膜电化学传感器(CTS/GR/CPE),并利用循环伏安法和线性扫描溶出伏安法研究了双酚A在电化学传感器上的电化学行为。在pH 7.4的磷酸盐缓冲液中,于-0.1V富集180s后,该电化学传感器对双酚A具有良好的电催化作用,于0.564V处有一灵敏的氧化峰,线性范围为1.00×10-6～7.00×10-5mol/L和7.00×10-5～1.00×10-3mol/L,检出限(S/N=3)为1.00×10-7mol/L。方法用于塑料制品中溶出双酚A的测定,回收率为96.4%～100.5%。     

表面接枝含氟苯乙烯共聚物的聚酯薄膜制备与表征

利用表面引发原子转移自由基聚合(SI-ATRP)在聚对苯二甲酸乙二醇酯(PET)薄膜表面接枝苯乙烯和4-氟苯乙烯的共聚物.研究不同反应时间和不同配比下接枝共聚物对聚酯薄膜表面组成、结构和性能的影响.通过傅利叶变换红外光谱仪(ATR/FTIR),X-射线光电子能谱仪(XPS),凝胶渗透色谱(GPC)和扫描电子显微镜(SEM)对接枝改性前后PET薄膜的表面组成,结构和形貌进行分析;利用接触角测试和表面能计算对比研究接枝改性前后PET薄膜的表面性能.结果表明反应时间和单体百分含量对接枝百分率及接触角有一定的影响,随着反应时间的增长,聚酯薄膜表面接枝百分率增大,接触角增加,表面自由能下降.