过渡金属配合物磁化率的测定与分析

介绍一个综合化学实验——过渡金属配合物的合成、磁化率测定及分析的实验教学方案。该实验以学习磁化率测试与分析为目的,通过对具有不同配位构型的镍(Ⅱ)配合物进行磁化率测定,结合单晶结构分析并通过晶体场理论解释其磁学性质,使学生既能掌握配合物合成的基本实验技术,又能了解配合物宏观磁化率与微观电子结构之间的关系。     

三唑-芳香多羧酸类混配金属配合物的结构与磁性能研究

以三唑为主配体的过渡金属配合物以其结构多样性及在磁性、吸附等功能材料中的潜在应用而成为众多科研工作者的研究热点内容之一．本文从三唑一芳香多羧酸混配配合物的合成以及芳香酸对配合物中金属一三唑次级结构的调节角度,总结了近年来报道的该类混配金属配合物的结构多样性．在此基础上,初步关联了该类混合配体顺磁金属配合物的磁一构关系．     

金属配合物分子纳米结构构筑与调控的STM研究进展

金属配合物分子具有结构多样且可控以及功能丰富等特点,在催化、传感、分子识别、纳米器件等领域得到广泛应用, 对金属配合物分子的研究已是分子科学研究中的热点之一.同时, 利用配合物分子构筑表面分子纳米结构以及对配合物单分子性质的研究也日趋活跃. 近年来, 本研究组发展了配合物分子在固体表面的自组装技术, 并结合扫描隧道显微技术(STM)开展了一系列有关金属配合物分子表面纳米结构的研究工作, 在固体表面成功实现了对配体、配合物分子的高分辨STM成像、原位配合以及分子识别, 设计和构筑了多种功能配合物分子纳米结构,并系统研究了结构形成规律. 本文以本研究组近年来有关金属配合物分子组装的研究结果为主, 结合国内外相关研究小组的研究结果,综述有关金属配合物分子纳米结构的构筑与调控的STM研究进展, 介绍该类分子在固体表面的组装和分散规律, 为表面分子纳米结构的构筑和调控提供理论和实验基础.     

基于核心素养发展的高中化学深度教学——探究配合物的性质

基于深度教学理论，从主体性、对话性和关联性，广度、深度和参与度等开展“配合物性质探究”的深度教学。以层层推进的探究实验和科学严谨的推理论证，建立配合物性质和结构的相互关系，搭建配合物电离平衡模型，逐步实现从宏观到微观，从定性到定量的高阶思维培养。在探讨问题的过程中，形成学科认识思路，发展化学学科核心素养。     

稀土元素共显色效应的研究 Ⅵ.镧-偶氮氯膦Ⅲ-钇混合多核配合物的生成

研究结果证实,用偶氮氯膦Ⅲ(CPAⅢ)以β型配合物测定钇时,镧的干扰属于一种共显色效应。共显色效应的实质,可能是形成了一种具有环状结构的镧-偶氮氯膦Ⅲ-钇的混合多核配合物。配合物中各组分的比例为La∶CPAⅢ:Y=1∶2∶1。本文还讨论了混合多核配合物生成的有关条件和各种影响因素。提出了“置换型”共显色效应的设想。     

主族金属氨基酸配合物的晶体学研究进展

主族金属配合物的研究是配位化学的重要主题之一. 相对于过渡金属和稀土金属配合物而言, 主族金属配合物的研究比较薄弱, 其主要原因在于: 主族金属的闭壳层电子层结构、有限的价电子数和较少的氧化态等特点, 使得主族金属与有机配体的相互作用较弱, 作用模式较为单一. 但近年来, 随着合成技术与分析检测技术的不断提升, 具有新颖结构并具有与过渡金属配合物相似的优良性能的主族金属配合物也不断地进入了人们的视野. 作为生物体的基本结构单元的氨基酸是一类良好的功能配体, 主族金属氨基酸配合物的研究具有重要的学术价值和应用价值, 也是化学、生物、医药和材料等众多学科领域中的共同的基本问题. 解决基本问题的一个切入点可能是研究这些新型主族金属氨基酸配合物的分子结构与物质结构. 因此, 本工作基于2000年以后发表的主族金属氨基酸配合物的晶体结构, 从X射线晶体学的研究视角, 分析了新型的主族金属氨基酸配合物的结构多样性, 包括当前热门的MOF类的结构; 综述了主族金属氨基酸配合物的研究进展; 展望了未来这一领域的发展方向; 提出了以功能为导向系统地开展主族金属氨基酸的配位化学和超分子化学的研究思路. 谨以此文献给2014年国际晶体学年.     

2-羟基-1-萘甲醛缩邻苯二胺席夫碱及其铜(Ⅱ)配合物的合成及组成测定——介绍一个大学化学综合实验

设计开发了一个大学化学综合性实验,合成了2-羟基-1-萘甲醛缩邻苯二胺席夫碱及其铜(Ⅱ)配合物,分别采用化学分析法和仪器分析法对配合物的组成进行了测定,并结合红外光谱、核磁共振氢谱对产物的结构进行了表征,取得了满意的实验结果。该实验一定程度上弥补了大学化学教学实验中合成有机金属配位化合物教学资源的匮乏。通过该实验的实施,可使学生进一步巩固回流、纯化、离心等基本操作技能,掌握摩尔比法测定配合物配位数及稳定常数的原理和方法,同时掌握运用有机波谱技术推断和鉴定分子结构的方法。本实验有利于培养学生综合运用有机化学、无机化学、化学分析及仪器分析等知识解决具体问题的能力,同时有利于学生了解席夫碱及其金属配合物的性质、研究动态等,激发学生对科学研究的热情,培养学生系统的科学思维和研究能力。     

基于深度学习构建探究实验设计思路*——以“探秘铜(II)离子配合物”为例

新课程背景下,依托教育部化学学科深度学习项目组提出的深度学习教学设计“四要素”,以配合物为例,开展深度学习,深入挖掘核心知识的素养功能和教育价值,促进学习方式转变,发展化学学科核心素养。     

高中化学“探秘配合物”的项目式教学——揭秘人体生命健康中的配合物

以“揭秘人体生命健康中的配合物”为项目研究主题,引导学生掌握配位键以及人体中配合物的存在和结构,并设计“调研人体中配合物的存在”“探究配位键的概念”“明确配合物的结构特征”“认识配合物的应用”“解释一氧化碳中毒的原理”等5个子任务。内容分为2个部分,第1部分以人体血红蛋白中的配位键为情境认识配合物的存在,第2部分从结构角度设置3个进阶梯度升华对配合物的认知,从宏观辨识到微观结构探析,提升学生对配合物的认知水平和学科素养,落实教、学、评一体化要求。     

含羧基席夫碱型配合物纳米结构材料的制备及谱学性质研究

采用对氨基苯甲酸分别与对苯二甲醛、间苯二甲醛反应, 制备出两种带有端羧基的席夫碱型配体. 控制一定条件, 与铁、钴、镍、铜、锌等过渡金属配位后得到一系列微观形貌不同的金属配合物纳米结构材料. 通过红外、XRD、TEM、SEM等表征手段, 考察了相应金属配合物纳米结构材料的结构与性质. 用荧光光谱考察配合物纳米结构材料的光致发光性能. 发现与原席夫碱型配体相比, 大部分配合物纳米结构材料表现出荧光淬灭现象, 但含Zn2＋的配合物纳米结构材料具有很好的荧光响应, 个别甚至优于配体本身的荧光强度, 表现为荧光增强效应. 以金属配合物纳米结构材料为基底, 考察其对探针分子(2-巯基苯并噻唑)的表面拉曼增强(SERS)性能. 结果发现, 通常具有较粗糙表面的配合物纳米结构材料对探针分子有一定的SERS效应.     

Gas-phase ion-molecule reactions of transition metal complexes: the effect of different coordination spheres on complex reactivity

Using a modified quadrupole ion trap mass spectrometer, a series of metal complex ions have been reacted with acetonitrile in the gas phase. Careful control of the coordination number and the type of coordinating functionality in diethylenetriamine-substituted ligands enable the effects of the coordination sphere on metal complex reactivity to be examined. The association reaction kinetics of acetonitrile with these pentacoordinate complexes are followed in order to obtain information about the starting complexes and the reaction dynamics. The kinetics and thermodynamics of acetonitrile addition to the metal complex ions are strongly affected by the chemical environment around the metal center such that significant differences in reactivity are observed for Co(II) and Cu(II) complexes with various coordination spheres. When thiophene, furan, or benzene moieties are present in the coordination sphere of the complex, addition of two acetonitrile molecules is readily observed. In contrast, ligands with better sigma donors react mainly to add one acetonitrile molecule. Among the ligands with good sigma donors, a clear trend in reactivity is observed in which complexes with nitrogen-containing ligands are the least reactive, sulfur-containing complexes are more reactive, and oxygen-containing complexes are the most reactive. In general, equilibrium and reaction rate constants seem to be consistent with the hard and soft acid and base (HSAB) principle. Interestingly, the presence of certain groups (e.g., pyridine and imidazole) in the coordination sphere clearly can change the acid character of the metal as seen by their effect on the binding properties of other functional groups in the same ligand. Finally, we conclude that because complexes with different coordination spheres react to noticeably different extents, ion-molecule (I-M) reactions may be potentially useful for obtaining coordination structure information for transition metal complexes.     

Solid-state white light-emitting electrochemical cells using iridium-based cationic transition metal complexes

White electroluminescent (EL) emission from single-layered solid-state light-emitting electrochemical cells (LECs) based on host-guest cationic iridium complexes has been successfully demonstrated. The devices show white EL spectra (Commission Internationale de l'Eclairage coordinates ranging from (x, y) = (0.45, 0.40) to (0.35, 0.39) at 2.9-3.3 V with high color rendering indices up to 80. Peak external quantum efficiency and peak power efficiency of the white LEC reach 4% and 7.8 lm/W, respectively. These results suggest that white LECs based on host-guest cationic transition metal complexes may be a promising alternative for solid-state lighting technologies.     

Complex Formation and Flower Colors

The pigment of the blue cornflower, protocyanin, is a complex of high molecular weight. Iron(III) and aluminum ions combine with the anhydro base of the cyanin to form deep-blue complexes, which are stable in the physiological pH range. Complexes of this type also have been synthesized. Alkali metal salts play no part in blue flower pigments. Formation of blue complexes can be prevented by sequestration of the metal ions with stronger complexing agents, e.g. flavonols. The variation of flower colors can be explained to a large extent on the basis of the complex formation of anthocyanins. In delphinidin glycosides, the color base or anhydro base is stable even in slightly acidic media.     

A Redox‐Active Dinuclear Platinum Complex Exhibiting Multicolored Electrochromism and Luminescence

A redox series of cyclometalated platinum complexes based on a dinuclear motif linked by acetamidato (aam) bridging ligands, [Pt₂(μ‐aam)₂(ppy)₂] (ppy^?=2‐phenylpyridinate ion), has been synthesized. The complexes in this series are easily oxidized and reduced by both electrochemical and chemical methods, and this is accompanied by multistep changes in their optical properties, that is, multiple color changes and luminescence. Isolation of the complexes and the structural determination of three oxidation states, +2, +2.33, and +3, have been achieved. The mixed‐valent complex, with an average oxidation state of +2.33, forms a trimer based on the dinuclear motif. The mixed‐valent complex has a characteristic color owing to intervalence transitions in the platinum chain. In contrast, the divalent complex exhibits strong red phosphorescence originating from a triplet metal‐metal‐to‐ligand charge transfer (³MMLCT) state. This study demonstrates the unique chromic behavior of a redox‐active and luminescent platinum complex.     

Observation of electroluminescence at room temperature from a ruthenium(II) bis-terpyridine complex and its use for preparing light-emitting electrochemical cells

A terpyridine ruthenium (II) complex containing a substituted and an unsubstituted terpyridine ligand was synthesized, and its luminescence properties were studied in a solid-state single-layer light-emitting electrochemical cell. The obtained devices emitted light of a very deep red color (CIE, x = 0.717 y = 0.282) at low external applied bias. It is the first example of an electroluminescence device based on a bis-chelated ruthenium complex. Its ambient atmosphere decay is remarkably different from analogous devices using tris-chelated ruthenium complexes.     

A redox series of gallium(III) complexes: ligand-based two-electron oxidation affords a gallium-thiolate complex

We have prepared a series of gallium(III) complexes of the redox active iminopyridine ligand (IP). Reaction of GaCl(3) with iminopyridine ligand (IP) in the presence of either two or four equivalents of sodium metal resulted in the formation of deep green (IP(-))(2)GaCl (1), or deep purple [(DME)(3)Na][(IP(2-))(2)Ga] (2a), respectively. Complex 1 is paramagnetic with a room temperature magnetic moment of 2.3 μ(B) which falls to 0.5 μ(B) at 5 K. These observations indicate that two ligand radicals comprise a triplet at room temperature which becomes a singlet due to antiferromagnetic coupling at low temperature. Complex 2 is diamagnetic. Cyclic voltammograms recorded on 0.3 M Bu(4)NPF(6) THF solutions of [Na(THF)(6)][(IP(2-))(2)Ga](-) (2b) indicate that oxidation of 2b occurs in two two-electron steps at -1.31 V and -0.54 V vs. SCE. The observation of two-electron redox events indicates that electronic coupling through the gallium(III) center is minimal and that the two IP ligand on 2b are oxidized concurrently. Oxidation of 2 with one equivalent of MeS-SMe afforded the two-electron oxidized product (IP(-))(2)Ga(SMe) (3). This complex has an electronic structure analogous to 1. Accordingly, both 1 and 3 are deep green in color and magnetic susceptibility measurements performed on 3 confirm the triplet character of the complex at room temperature. Electron paramagnetic resonance experiments on 1 and 3 display a quartet signal at g = 2.0 which confirmed the triplet nature of the compounds, and a half field signal consistent with the integer spin state.     

Thermochromism of metal ion complexes of semiquinone radical anions. Control of equilibria between diamagnetic and paramagnetic species by Lewis acids

Metal ion complexes of semiquinone radical anions exhibit different types of thermochromism depending on metal ions and quinones. Metal ion complexes of 1,10-phenanthroline-5,6-dione radical anion (PTQ(.-)) produced by the electron-transfer reduction of PTQ by 1,1'-dimethylferrocene (Me(2)Fc) in the presence of metal ions (Mg(2+) and Sc(3+)) exhibit the color change depending on temperature, accompanied by the concomitant change in the ESR signal intensity. In the case of Mg(2+), electron transfer from Me(2)Fc to PTQ is in equilibrium, when the concentration of the PTQ(.-)-Mg(2+) complex (lambda(max) = 486 nm) increases with increasing temperature because of the positive enthalpy for the electron-transfer equilibrium. In contrast to the case of Mg(2+), electron transfer from Me(2)Fc to PTQ is complete in the presence of Sc(3+), which is a much stronger Lewis acid than Mg(2+), to produce the PTQ(.-)-Sc(3+) complex (lambda(max) = 631 nm). This complex is in disproportionation equilibrium and the concentration of the PTQ(.-)-Sc(3+) complex increases with decreasing temperature because of the negative enthalpy for the proportionation direction, resulting in the remarkable color change in the visible region. On the other hand, the p-benzosemiquinone radical anion (Q(.-)) forms a 2:2 pi-dimer radical anion complex [Q(.-)-(Sc(3+))(2)-Q] with Q and Sc(3+) ions at 298 K (yellow color), which is converted to a 2:3 pi-dimer radical anion complex [Q(.-)-(Sc(3+))(3)-Q] with a strong absorption band at lambda(max) = 604 nm (blue color) when the temperature is lowered to 203 K. The change in the number of binding Sc(3+) ions depending on temperature also results in the remarkable color change, associated with the change in the ESR spectra.     

Structure of a terbium(III)-quinizarine complex: the first crystallographic model for metalloanthracyclines

The crystal structure of a complex of terbium(III) with quinizarine 2-sulfonate has been solved by single-crystal X-ray diffraction methods. The metal cation is coordinated by two adjacent phenolate and quinone oxygens of the anthraquinone moiety of a quinizarine sulfonate anion and by six water molecules. To our knowledge, this is the first structure of a metal complex of the 1,4-dihydroxy anthraquinone ligand. On the basis of strict similarities in the spectroscopic features of the terbium adducts with either doxorubicin or quinizarine 2-sulfonate, the present structure is proposed as a model for the metal complexes of anthracyclines.