Synthesis and magnetic properties of trinuclear copper(II) complexes bridged by dimethylglyoximate groups

Summary New three Cu^II-Cu^II-Cu^II homotrinuclear complexes have been synthesized, namely [Cu(dmg)₂{CuL}₂](ClO₄)₂ [L = 5-nitro-1,10-phenanthroline (5-NO₂-phen), 4,4-dimethyl-2,2-bipyridiine (DMbpy), tetramethylenediamine (TMDA) and dimethylglyoximate ion (dmg)^2-]. The magnetic susceptibilities of complexes (1) (L = 5-NO₂-phen) and (2) (L = DMbpy) were measured in the 4.2–300 K range, giving the parameters,J = -335cm^-1 (1) andJ= -327.5cm^-1 (2). The results demonstrate a very strong antiferromagnetic exchange interaction between the adjacent copper(II) ions.     

Synthesis and magnetic properties of trinuclear nickel(II) complexes bridged by α-benzyldioximato groups

Four new NiII–NiII–NiII homotrinuclear complexes namely [Ni(-BD)2{NiL2}](ClO4)2 [L = 1,10-phenanthroline (phen), 5-nitro-1,10-phenanthroline (5-NO2-phen), 2,2-bipyridyl (bpy) or 4,4-dimethyl-2,2bipyridyl (Me2bpy) and (-BD)– = -benzyldioximato ion] have been prepared and characterized. Based on elemental analyses, i.r. spectra, conductivity measurements, extended -benzyldioximato-bridged systems consisting of three nickel(II) ions in which the central nickel(II) ion has a square-planar environment and the end capped two nickel(II) ions have a distorted octahedral environment are proposed for these structures. The temperature dependence of the magnetic susceptibility for complexes (1) (phen), (2) (5-NO2-phen), (3) (bpy) and (4) (Me2bpy) were measured over the 77–300 K range and the observed data were successfully simulated by an equation based on the spin Hamiltonian operator (H^ = –2JS^1S^2), giving the exchange integral J = –13.31 cm–1 for (1), J = –7.37 cm–1 for (2), J = –8.96 cm–1 for (3) and J = –7.33 cm–1 for (4) These results indicate a weak antiferromagnetic spin exchange interaction between the two terminal nickel(II) io     

MnOx/Al-SBA-15的结构性质及低温NH3选择性催化还原NOx

采用后合成法制备MnO_x/Al-SBA-15催化剂, 考察了催化剂的低温NH₃选择性催化还原(SCR)NO_x的性能. 利用傅里叶透射红外变换(FTIR)光谱、N₂吸附-脱附、X射线衍射(XRD)、扫描电镜(SEM)、拉曼光谱(Raman)、X射线光电子能谱(XPS)及NH₃程序升温脱附(NH₃-TPD)的表征手段, 对催化剂的结构性质和SCR性能进行了系统分析. 结果表明, 适量Al的掺杂能提高MnO_x/SBA-15催化剂的SCR活性, 当硅铝摩尔比为50时, 催化剂活性最佳. 表征结果显示, Al掺杂后, 催化剂仍保持良好的骨架结构, 较大比表面、孔容和孔径, 并且Mn在催化剂表面富集, 由低价态转化为高价态, MnO₂为催化剂的主要活性相. 此外, Al的掺杂使MnO_x在催化剂表面高度分散, 表面酸性增强, 从而提高了催化剂的SCR活性.     

纳米纤维固相萃取-高效液相色谱-荧光检测麻辣烫汤液中喹诺酮类药物

建立了固相萃取-高效液相色谱-荧光检测麻辣烫汤液中5种喹诺酮类抗生素的分析方法。麻辣烫汤液样品经EDTA-Mcllvaine缓冲溶液(pH 4)提取后,以HCX固相萃取小柱净化富集,用水淋洗,2%氨化甲醇洗脱。采用高效液相色谱-荧光检测器(HPLC-FLD),于激发波长280 nm,发射波长450 nm处进行检测,流动相为甲醇-水-磷酸(25∶75∶0.1,V/V,三乙胺调至pH 2.8)。麻辣烫汤液样品中氟罗沙星、诺氟沙星、沙拉沙星、环丙沙星、奥比沙星5种喹诺酮类抗生素加标回收率为72.1%~110.3%;日内相对标准偏差(RSD)为1.6%~4.3%,日间相对标准偏差为2.0%~4.3%;检出限(LOD)为1.2~5.4μg/L;定量限(LOQ)为3.9~18μg/L。本方法能够满足实际麻辣烫汤液样品的分析要求。     

白藜芦醇对长期贮存锂离子电池电解液性能的影响

锂离子电池电解液从制造完成到使用,一般都会经历灌装、运输和贮存的过程,了解长期贮存过程对锂离子电池电解液性能的影响,对锂离子电池的生产具有一定的理论指导意义.本文运用电化学阻抗谱(EIS)测试并结合循环伏安法(CV)测试、充放电测试、扫描电子显微镜(SEM)等研究了1 mol.L-1 LiPF6-EC:EMC 基础电解...     

K3PO4 promoted dipolar [3+3] cyclization: Direct synthesis of pyrazino[2,1-a]isoquinoline derivatives

A K₃PO₄ promoted dipolar [3+3] cyclization of dihydroisoquinoline imines and arylacyl bromides has been developed. This process realized the direct synthesis of pyrazino[2,1-a]isoquinoline derivatives in 44–69% yields. A head to tail dimerization was proposed as key step for this procedure.     

Synthesis and magnetic properties of copper (II)-manganese (II) compounds with N,N′-ethylenedisalicylamidatocuprate(II)

By the reaction of sodium N,N′-ethylenedisalicylamidatocuprate ( I ) pentahydrate, Na₂[Cu(samen)]·5H₂O, with a manganese ( I ) salt and 2,2′-dipyridyl (bpy) or 1,10-phenanthroline (phen), the binuclear metal complexes [Cu(samen) Mn(L)₂] (L ? bpy, phen) have been synthesized. Based on IR, elemental analyses and electronic spectra, the complexes are proposed to consist of a four-coordinated Cu( I ) in a distorted planar environment and Mn( I ) in a distorted octahedron. The complexes have been characterized with variable-temperature magnetic susceptibility (4.2—300 K) and the susceptibility data were least-squares fit to susceptibility equation derived from the spin Hamiltonian including single-ion zero-field interaction for Mn²⁺ ion, H?—2JS₁·S₂—DS, where D is the axial zero-field splitting parameter for the Mn(II) ion. The exchange integral, J, was found to be —34.6 and —28.8 cm^?1 for [Cu(samen)Mn(bpy)₂] and [Cu(samen)Mn(phen)₂] respectively. The weak antiferromagnetic spin-exchange interaction can be interpreted by considering σ-π exchange pathway.     

姜黄素桥连卟啉光敏剂的合成及表征

为了开发新的高效光动力治疗光敏剂, 以2-(2-羟基萘基)-5,10,15,20-四苯基卟啉及其Cu(Ⅱ), Ni(Ⅱ), Zn(Ⅱ)配合物为原料, 利用1,6-二溴己烷桥连具有抗癌活性的小分子姜黄素, 设计合成4个新型的天然产物桥连卟啉化合物. 通过UV, ¹H NMR, IR, MS及元素分析等手段对该新型光敏药剂进行了结构表征; 在此基础上, 采用凝胶电泳法考察了化合物在光照和无光照条件下对pBR322质粒DNA的切割能力. 作为潜在光敏剂与DNA相互作用的初步研究表明, 其与DNA结合能力较强, 具有明显的光敏切割效果.     

A generalized variant of two-sweep modulus-based matrix splitting iteration method for solving horizontal linear complementarity problems

Numerical Algorithms - Based on the two-sweep modulus-based matrix splitting iteration (TMMS) method for linear complementarity problems developed by Wu and Li (Comput. Appl. Math. 302:...     

[Cp*Rh(CO)2Me]BF4和二环庚二烯的反应机理研究

[Cp^*Rh(CO)₂Me]BF₄与二环庚二烯反应生成的含五元环产物可以作为烯烃/羰基共聚的潜在催化剂。本文采用密度泛函(DFT)方法对该类反应的机理进行了研究。研究表明，甲基转移是整个反应的决速步骤。计算得到，该步反应的活化焓变为71.67 kJ·mol^-1, 跟实验中得到的相应的焓变值(72 ± 2 kJ·mol^-1)吻合得很好。计算结果同时证实，该反应在热力学上非常有利。结构分析表明，二环庚二烯和金属中心配位后，二环庚二烯内的环张力得以释放以及螯合环的生成是导致热力学有利的主要原因。