Pulse radiolysis of one-electron oxidation of rare tricyclic nucleoside derivative

~~Pulse radiolysis of one-electron oxidation of rare tricyclic nucleoside derivative@赵红卫$Shanghai Institute of Nuclear Research, Chinese Academy of Sciences! Shanghai 201800,China @江致勤$Department of Chemistry, Tongji Unviersity!Shanghai 200092,China @窦大营$Shanghai Institute of Nuclear Research, Chinese Academy of Sciences! Shanghai 201800,China @吴铁一$Shanghai Institute of Nuclear Research, Chinese Academy of Sciences! Shanghai 201800,China @王文锋$Shanghai…     

Asymmetric Henry reaction catalyzed by C2-symmetric tridentate bis(oxazoline) and bis(thiazoline) complexes: metal-controlled reversal of enantioselectivity

[reaction: see text] C(2)-symmetric tridentate bis(oxazoline) and bis(thiazoline) ligands with a diphenylamine backbone have been investigated in the catalytic asymmetric Henry reaction of alpha-keto esters with different Lewis acids. Their Cu(OTf)(2) complexes furnished S enantiomers, while Et(2)Zn complexes afforded R enantiomers, both of them with higher enantioselectivities (up to 85% ee). Reversal of enantioselectivity in asymmetric Henry reactions was achieved with the same chiral ligand by changing the Lewis acid center from Cu(II) to Zn(II). The results show that the NH group in C(2)-symmetric tridentate chiral ligands plays a very important role in controlling both the yields and enantiofacial selectivity of the Henry products.     

Selective synthesis and characterization of single-crystal silver molybdate/tungstate nanowires by a hydrothermal process

Selective synthesis of uniform single crystalline silver molybdate/tungstate nanorods/nanowires in large scale can be easily realized by a facile hydrothermal recrystallization technique. The synthesis is strongly dependent on the pH conditions, temperature, and reaction time. The phase transformation was examined in details. Pure Ag(2)MoO(4) and Ag(6)Mo(10)O(33) can be easily obtained under neutral condition and pH 2, respectively, whereas other mixed phases of Mo(17)O(47), Ag(2)Mo(2)O(7,) Ag(6)Mo(10)O(33) were observed under different pH conditions. Ag(6)Mo(10)O(33) nanowires with uniform diameter 50-60 nm and length up to several hundred micrometers were synthesized in large scale for the first time at 140 degrees C. The melting point of Ag(6)Mo(10)O(33) nanowires were found to be about 238 degrees C. Similarly, Ag(2)WO(4), and Ag(2)W(2)O(7) nanorods/nanowires can be selectively synthesized by controlling pH value. The results demonstrated that this route could be a potential mild way to selectively synthesize various molybdate nanowires with various phases in large scale.     

时间分辨激光荧光光谱分析方法研究——Ⅰ.铽、镝配合物共存时的分辨原理实验

本文对镝存在时铽的测定,进行了时间分辨激光荧光光谱分析方法的原理性实验。选择Tb、Dy-Sal乙醇溶液体系,测量了Tb~(3+)离子浓度范围为0.01～10μg/ml。Dy~(3+)离子浓度为0.1～100μg/ml范围内的荧光寿命。并得到了此范围内配合物离子浓度与荧光强度具有线性关系的结果。     

氢化物发生—分光光度法测定染发剂中的微量铅

本文提出了用铁氰化钾将铅氧化至高价,再用氢化物发生-分光光度法测定铅的一种新方法。该法灵敏度高,简便快速,用于分析染发剂中的铅,取得了较好的效果。     

γ-氨丙基硅氧烷与八甲基环四硅氧烷乳液共聚合的研究

合成了γ-氨丙基七甲基环四硅型氧烷和γ-氨丙基甲基二乙氧基硅烷。研究了它们与八甲基环四硅氧烷在阳离子乳化剂及阴离子型乳化剂存在下的乳液共聚合反应。探讨了催化剂量、单体浓度、氨丙基含量及温度等对聚合的影响。     

Direct electrochemical detection of glucose in human plasma on capillary electrophoresis microchips

We developed an electrochemical detector on a hybrid chip for the determination of glucose in human plasma. The microchip system described in this paper consists of a poly(dimethylsiloxane) (PDMS) layer containing separation and injection channels and an electrode plate. The copper microelectrode is fabricated by selective electroless deposition. The fabrication of the decoupler is performed by platinum electrochemical deposition on the metal film formed by electroless deposition. Factors influencing the performance, including detection potential, separation field strength, and buffer concentration, were studied. The electrodes exhibited good stability and durability in the analytical procedures. Under optimized detection conditions, glucose responded linearly from 10 microM to 1 mM. Finally, glucose in human plasma from three healthy individuals and two diabetics was successfully determined, giving a good prospect for a new clinical diagnostic instrument.     

硼烷缺电子多中心桥键的H-F力研究

Hellmann-Feynman静电力表现了分子中电荷分布及对各原子核的作用。H-F力的方向性可描述电子电荷的数量和位置,具有定量、形象和直观的特点,已在弯键的研究中显示出来。这一方法尚可用于多中心缺电子桥键的研究。 1 理论与方法 按LCAO-MO理论对H-F力进行分解,除有重叠力、极化力和屏蔽力外,还有一     

Regioselective palladium-catalyzed phenylation of ethyl 4-oxazolecarboxylate

The efficient and regioselective palladium-catalyzed C-2 arylation of ethyl 4-oxazolecarboxylate 1 with phenyliodide is described. The different parameters (solvent, base, ligand and catalyst) for the optimal conditions of this arylation process have been screened.     

Gold(III) complexes with imidazole,benzoxazole, purine and pyrimidine derivatives

Summary The synthesis and characterization of Au^III complexes with several heterocyclic ligands are reported. The compounds have general formula [AuX₃(L)], where L =N-methylimidazole (N-MeIz),N-ethylimidazole (N-EtIz),N-propylimidazole (N-PrIz), benzoxazole (BO), 2-methylbenzoxazole (2-MeBO), 2,5-dimethylbenzoxazole (2,5-diMeBO), 2-amino-pyrimidine (2-APm), 4(6) -hydroxy-pyrimidine [4(6)-hydrPm] or hypoxanthine (Hypox) and X = Cl or Br. Elemental analysis, conductivity measurements and spectral studies were used for the characterization of the complexes. A square-planar geometry withN-bonded heterocyclic ligands is suggested.