甲基吡啶侧链金属化和烷基化反应的研究

甲基吡啶侧链上的氢易于质子化被碱金属所取代,但传统的侧链金属化的方法,其实验操作都比较繁复。前文报道,吡啶与金属钠在乙醚回流中可形成吡啶自由基负离子钠络合物(C_5H_5N~-Na~ ),它是一种有效的金属     

基于衣康酸配体构筑的两个锌配合物的合成、结构和荧光性质

通过水热法合成了两种锌配位聚合物{[Zn(ic)(bip)]·2H₂O}n (1)和[Zn(ic)(bpe)]n (2)(H₂ic=衣康酸,bip=3,5-二(1-咪唑基)吡啶,bpe=1,2-二(4-吡啶基)乙烯),并通过X射线单晶衍射和元素分析对其结构进行了表征.配合物1和2均为含有一维金属-羧酸链的二维(4,4)格子层结构.此外,对它们的热重、粉末X射线衍射和固体荧光性能进行了考察.与配体bip相比,1的发射光谱发生了明显的蓝移(~78 nm),可能归因于配体到金属的电荷转移;2显示与游离的bpe配体相似的荧光性质,轻微的红移可能是因为与金属离子之间的配位作用导致的.     

Giant magnetoresistance effect in nanostructures consisting of magnetic–electric barriers

The GMR effect in magnetic–electric barrier nanostructure, which can be realized experimentally by depositing two parallel metallic ferromagnetic strips with an applied voltage on the top of heterostructure, is investigated theoretically. It is shown that a considerable GMR effect can be achieved in such nanosystems due to the significant transmission difference for electrons tunneling through parallel and antiparallel magnetization configurations. It is also shown that the magnetoresistance ratio is strongly dependent upon the applied voltage to metallic ferromagnetic strips in nanosystems, thus may leading to voltage-tunable GMR devices.     

基于柠康酸构筑的三个配合物的合成、结构与性能

在水热条件下,制备出3个配位聚合物,即{[Zn（ca）（iimb）]·0.75H₂O}_n（1）,{[Cd（ca）（iimb）（H₂O）]·0.75H₂O}_n（2）和{[Zn（ca）（bpe）_0.5（H₂O）]·H₂O}_n（3）（H₂ca=柠康酸,iimb=1-（1-咪唑基）-4-（咪唑基-1''-甲基）苯,bpe=1,2-二（4-吡啶基）乙烯）,并通过单晶X射线衍射、红外光谱和元素分析进行结构表征。配合物1是含有一维金属羧酸链的二维网状层。2是具有羧酸桥连双核的一维准梯形链状结构。3是二维波浪层。其中2和3的三维超分子结构由丰富的氢键相互作用形成;而1的三维超分子结构通过范德华力堆积而成。研究了3个配合物的热重分析（TGA）,粉末X射线衍射（PXRD）和荧光性质。固态荧光光谱表明3个配合物的发射光谱与相应的辅助配体相似。此外,配合物3在紫外光照射下,在H₂O₂存在时对亚甲基蓝（MB）的降解表现出良好的光催化活性。     

基体溶液改进-原子荧光法测定食品中的汞

探讨改进基体溶液双道原子荧光光谱法测定食品样品中的汞。样品消解后用6mol/L盐酸、硫脲+抗坏血酸(50g/L)作为基体溶液进行仪器测定。本方法检出限0.051μg/g,最低检出质量浓度0.10μg/L,相对标准偏差为7.45%、6.76%,回收率为88.6%—113.2%。方法具稳定性好、灵敏度高、检出限低等优点。     

Syntheses,structures and magnetic properties of three cobalt(II) coordination polymers based on flexible itaconic acid ligands

Transition Metal Chemistry - Three Co(II) coordination polymers, namely [Co(ia)(bpe)0.5(H2O)]n (1), {[Co(ia)(bib)(H2O)]·H2O}n (2) and {[Co(ia)(btmb)(H2O)]·H2O}n (3)...     

A Novel 3D Cu(Ⅱ) Coordination Polymer Containing Mixed Ligands: Synthesis,Crystal Structure and Properties

A novel compound, {[Cu2(nbdc)2(4,4'-bpy)2(H2O)2]·2H2O}n(H2nbdc = 4-nitrobenzene-1,2-dicarboxylic acid, 4,4'-bpy = 4,4'-bipyridine), was hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis(TGA), and single-crystal X-ray diffraction. The complex is of orthorhombic system, space group Pbcn with a = 32.222(7), b = 7.8503(16), c = 28.389(6), V = 7181(3)3, Dc = 1.720 g/cm3, Mr = 929.74, Z = 8, F(000) = 3792, μ = 1.273 mm-1, the final R = 0.0591 and wR = 0.1378 for 4548 observed reflections with I 2σ(I). The compound exhibits a 3D self-penetrating framework with bcu net topology, in which the(46·48)-networks are joined by the H2nbdc and 4,4'-bpy linkers.     

乙醇/Tris-水中Cu(Ⅱ)对SDS和DNA增强[Ru(bpy)2(dppz)]2+光致发光的调控

应用荧光光谱、荧光显微镜和伏安法研究了乙醇/水体系中Cu(Ⅱ)对十二烷基硫酸钠(SDS)和鱼精DNA增强[Ru(bpy)₂(dppz)]²⁺(bpy=2,2′-联吡啶, dppz=邻联二吡啶[3,2-a:2′,3′-c]吩嗪)光致发光的调控。结果表明, 在乙醇/三羟甲基氨基甲烷(Tris)-水 (V_乙醇:V_Tris=1:5)体系中, DNA和阴离子表面活性剂SDS均能增强[Ru(bpy)₂(dppz)]²⁺的光致发光, 其与[Ru(bpy)₂(dppz)]²⁺间的键合常数分别为5.5×10⁵和4.2×10² L·mol^-1;Cu(Ⅱ)离子能通过DNA和SDS介导的光诱导电子转移淬灭乙醇/水溶液中[Ru(bpy)₂(dppz)]²⁺的光致发光, DNA介导的Stern-Volmer淬灭常数为2.0×10⁵ L·mol^-1, 远远大于SDS介导的淬灭常数(9.0×10³ L·mol^-1)。此外, 结合SDS、DNA和Cu(Ⅱ)对[Ru(bpy)₂(dppz)]²⁺在铟锡氧化物(ITO)电极上发生的氧化还原反应的影响, 进一步探讨了乙醇/Tris-水中Cu(Ⅱ)对SDS和DNA增强[Ru(bpy)₂(dppz)]²⁺光致发光的调控机理。该研究有助于更好地理解DNA嵌入剂的发光和淬灭机制, 为生物分子光开关的构建提供新思路。     

基于衣康酸配体构筑的两个锌配合物的合成、结构和荧光性质

通过水热法合成了两种锌配位聚合物{[Zn（ic）（bip）]·2H₂O}_n（1）和[Zn（ic）（bpe）]_n（2）（H₂ic=衣康酸,bip=3,5-二（1-咪唑基）吡啶,bpe=1,2-二（4-吡啶基）乙烯）,并通过X射线单晶衍射和元素分析对其结构进行了表征。配合物1和2均为含有一维金属-羧酸链的二维（4,4）格子层结构。此外,对它们的热重、粉末X射线衍射和固体荧光性能进行了考察。与配体bip相比,1的发射光谱发生了明显的蓝移（⁷8 nm）,可能归因于配体到金属的电荷转移;2显示与游离的bpe配体相似的荧光性质,轻微的红移可能是因为与金属离子之间的配位作用导致的。     

One-dimensional Coordination Polymers Assembled into Two Supramolecular Frameworks with High Stability

The dual ligand system of V-shaped 5-(4-carboxy-2-nitrophenoxy)-isophthalic acid(Hcn-H2ipa) and dipyridy-type molecules produces two new coordination polymers: {[Ni(cn-Hipa)(bpa)(H2O)3]·1.5H2O}n 1 and {[Cu(Hcn-ipa)(ppe)2]}n 2(bpa = 1,2-bis(4-pyridyl)ethane, and ppe = trans-1-(2-pyridyl)-2-(4-pyridyl)ethylene). Two complexes have been characterized by single-crystal X-ray diffraction, elemental analysis, IR, and thermogravimetric analysis(TGA). Complex 1 is of monoclinic system, space group C2 with a = 25.936(3), b = 7.6100(10), c = 16.558(2), β = 105.9470(10)°, V = 3142.4(7) ?3, Dc = 1.415 g/cm3, Mr = 669.23, Z = 4, F(000) = 1388, μ = 0.687 mm-1, the final R = 0.0397 and w R = 0.0967 for 12070 observed reflections with I 2σ(I). Complex 2 belongs to the triclinic system, space group P1 with a = 10.165(5), b = 14.946(7), c = 15.506(11) ?, α = 106.461(7), β = 102.454(8), γ = 107.861(5)°, V = 2029(2) ?3, Dc = 1.266 g/cm3, Mr = 773.20, Z = 2, F(000) = 794, μ = 0.595 mm-1, the final R = 0.0538 and w R = 0.1378 for 15488 observed reflections with I 2σ(I). Two complexes show that the 1D polymeric chains are cohered together by extensive H-bonds to complete stable supramolecular microporous frameworks.