草酸根桥联手性双核铜的合成、表征、结构与磁性

分别以(8R,10R)-(-)-[4,5]-pineno-2,2′-bipyridine或(8S,10S)-(+)-[4,5]-pineno-2,2′-bipyridine(LRR和LSS)为手性配体合成双核铜络合物[Cu2(μ-ox)(LRR)2(H2O)2(ClO4)2](1)、[Cu2(μ-ox)(LRR)2(CH3COCH3)2(ClO4)2](1a)、[Cu2(μ-ox)(LSS)2(H2O)2(ClO4)2](2)和[Cu2(μ-ox)-(LRR)(LSS)(CH3COCH3)2(ClO4)2](3)(ox2-=草酸根),并探讨了其反应机理.由元素分析、电导率、紫外可见谱(UV-vis)、圆二色(CD)谱和晶体结构分析推测:该系列络合物具有草酸根桥联的双核结构,两个铜(II)离子与草酸根几乎成共平面;1a和3的晶体结构分析表明,每个Cu(II)的配位构型为拉长畸变八面体,双核分子中轴向的两个溶剂分子和两个高氯酸根互为反式配位.对映体络合物1和2的溶液CD光谱大致呈镜像对称,在可见区的极弱CD吸收峰可能源于LRR和LSS蒎烯基上的手性中心对Cu(II)d-d生色团的手性微扰产生的邻位效应.采用最小二乘法和Bleaney-Bowers方程对络合物1的变温磁化率测试数据进行拟合,求得交换积分J=-338.41(4)cm-1,表明铜(II)离子间有较强的反铁磁自旋交换作用.     

利用天然手性源合成复杂手性化合物的方法

利用天然手性源来合成一些复杂的手性化合物,其合成策略往往具有很高的艺术性.本文主要对糖类和甘露糖以及一些氨基酸类天然产物作为合成子来合成手性分子的一些新方法作了报道.     

正电子发射断层显像剂[18F]FET前体N-叔丁氧羰基-O-(2-三氟甲磺酰氧乙基)-L-酪氨酸甲酯/叔丁酯的合成

本文合成了正电子发射断层显像剂[¹⁸F]FET的两个新型前体：N-叔丁氧羰基-O-(2-三氟甲磺酰氧乙基)-L-酪氨酸甲酯9a和N-叔丁氧羰基-O-(2-三氟甲磺酰氧乙基)-L-酪氨酸叔丁酯9b. 化合物9a或9b以L-酪氨酸为原料, 先与甲醇发生酯化反应或与乙酸叔丁酯进行酯交换, 再用叔丁氧羰基保护氨基, 接着在苯环的酚羟基上引入羟乙基, 最后与三氟甲磺酸酐反应形成目标化合物, 这四步反应总收率分别是30%或15%.     

Different self-assembly behaviors of mono-modified β-cyclodextrin substituted by benzoic acid derivatives

The mono-modified β-cyclodextrin derivative,6-O-(4-aminobenzoyl)-β-cyclodextrin(1) ,was synthesized and characterized. We compared its self-assembling behavior with structurally related β-cyclodextrin derivative,6-O-(4-hydroxybenzoyl)-βcyclodextrin(2) ,in aqueous solution and in the solid state using NMR spectroscopy and single crystal X-ray structure analysis. The two complexes displayed different self-assembling behaviors.Complex 1 formed a head-to-tail helical columnar superstructure in which the substit...     

Et_3NHCl-AlCl_3催化苯与1-十二烯烃烷基化反应机理的研究

本文利用同位素取代法考察了离子液体催化苯与烯烃烷基化反应机理.首先进行了Et3NHCl-AlCl3催化氘代苯与1-十二烯烃的反应,通过GC-MS及NMR分析产物结构,根据分析结果,在反应过程中一个D原子从苯环转移到侧链的1-碳.由此推断离子液体催化苯与长链烯烃的烷基化反应机理为:反应由Lewis酸AlCl3引发;AlCl3吸引1-十二烯烃的π电子向1-碳转移,形成碳正离子;碳正离子进一步与苯反应形成不稳定的σ络合物,σ络合物苯环上的sp3杂化碳相连的D+转移到侧链的负电1-C上取代AlCl3,生成产物2-十二烷基苯.     

Catalytic selective oxidation or oxidative functionalization of methane and ethane to organic oxygenates

Selective oxidation or oxidative functionalization of methane and ethane by both homogeneous and heterogeneous catalysis is presented concerning: (1) selective oxidation of methane and ethane to organic oxygenates by hydrogen peroxide in a water medium in the presence of homogeneous osmium catalysts, (2) selective oxidation of methane to formaldehyde over highly dispersed iron and copper heterogeneous catalysts, (3) selective oxidation of ethane to acetaldehyde and formaldehyde over supported molybdenum cat...     

Adsorptive desulfurization on a heteroatoms Y zeolite prepared by secondary synthesis

Gallium atoms have been introduced into the framework of Y zeolite by treating the zeolite with an aqueous solution of ammonium hexafluoro gallate.Desulfurization of various model fuels containing about 500 μg/g sulfur has been studied over the synthesized Y zeolite(GaAlY).The sulfur adsorption capacity is 7.0,17.4,14.5,16.9,6.9 and 5.8 mg(S)/g adsorbent for thiophene,tetrahydrothiophene(THT),4,6-dimethyldibenzothiophene(4,6-DMDBT),dibenzophiophene(DBT),benzothiophene(BT) and 4-methyldibenzothiophene(4-MDBT...     

高分子辅助的纳米粒子造影增强材料

纳米技术和纳米医学的研究在生物医学、疾病诊断和治疗方面显示出了巨大的应用潜力. 有机荧光分子基检测技术已被广泛的用作造影和信号转换的工具用以测定痕量的分析物. 然而, 有机荧光分子基团的降解、光漂白作用使得其荧光的稳定性受到影响, 从而限制了它们在复杂的生理环境中的应用. 无机纳米粒子因其形状、尺寸和组成的不同而具有独特且稳定的光、电、磁及催化性能, 可用作新型的生物纳米造影材料, 能很好的解决造影检测技术所面临的难题. 并且, 纳米造影材料的表面修饰则可以提高它们的在生理条件下的稳定性和靶向生物活性分子的能力.     

Construction and evaluation of a novel end-column amperometric detection system for electrophoresis microchips

A set of integrated end-column amperometric detection system has been developed,onto which an electrophoresis microchip can be conveniently integrated.Finely machined by a piece of transparent organic glass,the system consists of an electrophoresis microchip platform and an amperometric detection reservoir,in which the microchip can be fixed onto the platform by microchip grooves and with stainless steel fixture.Each detection electrode can be directly fixed in the amperometric detection reservoir by screws...     

Optimal paths for a light-driven engine with a linear phenomenological heat transfer law

An irreversible light-driven engine is described in this paper, in which the heat transfer between the working fluid and the environment obeys a linear phenomenological heat transfer law [ q ∝Δ(T -1)], with a working fluid composed of the bimolecular reacting system 2SO 3 F■S 2 O 6 F2. Piston trajectories maximizing work output and minimizing entropy generation are determined for such an engine with rate-dependent loss mechanisms of friction and heat leakage. The optimal control theory is applied to determi...