共查询到20条相似文献,搜索用时 31 毫秒
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本文提出了在非限制Hartree-Fock方法计算的分子轨道基础上,计算分子价电子体系能谱和多电子状态的不可约张量方法。使用这种方法,计算了具有近似正八面体对称性的过渡金属化合物MnBr_6~(4-)、MnCl_6~(4-)、FeCl_6~(3-)、MnF_6~(4-)、Mn(H_2O)_6~(2+)、Co(NH_3)_6~(3+)、NiF_6~(4-)、Ni(H_2O)_6~(2+)、Ni(NH_3)_6~(2+)的d-d跃迁能谱。理论计算结果与实验符合较好,误差为若干k cm~(-1) 相似文献
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Raymond F. X. Williams 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-3):141-146
Abstract A new sulfur containing oxocarbon derivative, the dipotassium salt of 1,2-dimercapto-3,4,5-cyclopentenetrione (potassium dithiocroconate) has been synthesized by reaction of dimethyl croconate with alcoholic potassium hydrogen sulfide. Solutions containing the dianion of this salt react to form intensely colored complexes of varying hues with several transition metal ions. Spectral and esr measurements on Ni(II) and Cu(II) indicate complexes with 2:1 ligand/metal ratio having dithiolene properties are formed in solution. Visible-uv and infrared studies suggest dithiocroconate dianion has less resonance stabilization than croconate dianion. 相似文献
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ms-四咪唑基卟啉络合金属离子的能力及其金属络合物的催化性能 总被引:1,自引:0,他引:1
本文考察了两种ms-四咪唑基卟啉〔H2T(2-I)P和H2T(4或5-I)P〕对锌离子的络合能力,并与ms-四苯基卟啉〔H2TPP〕进行了比较。用ms-四咪唑基金属卟啉〔MT(2-I)P和MT(4或5-I)P〕作为催化剂,以分子氧为氧源,考察了对氢醌、异丙硫醇和抗环血酸三种底物氧化反应的催化活性。在后一底物的氧化反应中对CoT(2-I)P,CoT(4或5-I)P和CoTPP进行了对比。此外,还用EHMO程序计算了卟吩、ms-四咪唑基卟啉、ms-四苯基卟啉及其锌络合物的净电荷分布和能量,对反应结果作了比较满意的解释。 相似文献
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《Journal of Coordination Chemistry》2012,65(14):2239-2260
Much work has been focused on interactions of metal ions with nonsteroidal anti-inflammatory drugs (oxicams). Numerous attempts to synthesize several metal complexes have been published. This review highlights the synthesis and properties of the synthesized metal complexes. Different physico-chemical methods (IR, UV–Vis, measurement, thermal analysis, and NMR spectroscopy) as well as the bioactivity of the metal compounds are mentioned. 相似文献
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络合物稳定常数的计算 总被引:2,自引:0,他引:2
陈与德 《高等学校化学学报》1980,1(1):9
本文介绍了计算络合物稳定常数的八种方法,它们是:1.lgK1=Az2/r+Bx±+C.2.两相似金属离子与一系列配位体络合时,lgK1间一的线性关系。3.两相似配位体与一系列金属离子络合时,lgK1间的线性关系。4.一系列相似配位体与同一金属离子络合时,lgK1与∑pKa间的线性关系。5.一系列相近z2/r的金属离子与同一配位体络合时lgK1与x±间的线性关系。6.一系列相近x的金属离子与同一配位体络合时lgK1与z2/r间的线性关系。7.金属离子随z2/r和x而变化的络合次序。8.∑pKa较大的配位体与z2/r较大的金属离子匹配,电负性较小的配位体与电负性大的金属离子匹配。 相似文献
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《高分子科学杂志,A辑:纯化学与应用化学》2013,50(4):429-449
Metal ion specificity studies of divinylbenzene (DVB)-crosslinked polyacrylamide-supported glycines in different structural environments were investigated. The effect of the degree of crosslinking on the specific rebinding of the desorbed metal ion was investigated towards Co(II), Ni(II), Cu(II), and Zn(II) ions. The metal ion-desorbed resins showed specificity for the desorbed metal ion and the specificity characteristics increases with an increasing degree of the crosslinking agent. The polymeric ligands and metal complexes were characterized by IR, UV-visible and EPR spectra, and by SEM analysis. The swelling and solvation characteristics of the crosslinked polymers, polymeric ligands and metal complexes, the effect of the pH dependence on metal ion binding and rebinding and the kinetics of metal ion binding and rebinding were also followed. The complexation resulted in the downfield shift of the carboxylate peak in the IR spectra. The EPR parameters are in agreement with a distorted tetragonal geometry. The Cu(II) ion-desorbed resins selectively rebinds Cu(II) ions from a mixture of Cu(II) and Co(II) and Cu(II) and Ni(II) ions. The resin could be regenerated several times without loss of capacity and effective for the specific and selective rebinding of Cu(II) ions. 相似文献
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通过固相合成方法将聚酰胺-胺树状分子担载于氯球上,对其外围分别用2,4-二羟基苯甲醛和邻羟基苯甲醛进行修饰,再与SnCl2.2H2O反应,形成配体不同的两类树状高分子锡配合物.将此类配合物用作30%的双氧水氧化酮的Baeyer-Villiger反应的非均相催化剂,具有较好的催化活性.2-金刚烷酮、环己酮、3-甲基-2-戊酮等都转化为相应的酯和内酯,底物的转化率和产物选择性均较高.对2-羟基苯甲醛、2,4-二羟基苯甲醛和邻羟基苯甲醛修饰的不同类型催化剂催化下的反应进行比较,发现配体对锡的担载量和催化活性均有不同程度的影响.其中邻羟基苯甲醛修饰的配合物因具有较高的锡担载量而具有了最佳的催化活性.此催化体系使用环境友好的低浓度双氧水为氧化剂,催化剂制备方法简单、催化反应完成时间短、催化剂在多次重复利用后活性没有明显降低,可回收和重复利用. 相似文献
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Gianluca Ambrosi Mauro Formica Vieri Fusi Luca Giorgi Mauro Micheloni 《Coordination chemistry reviews》2008,252(10-11):1121
The coordination properties of a selected series of acyclic and macrocyclic ligands containing one or more phenolic groups are explored. The formation of polynuclear metal complexes was only considered highlighting the key role played by the phenoxide oxygen atom in binding two metal centres in a bridge disposition. This arrangement allows two metal ions to stay close each other and consequently these dinuclear centres are able to mimic many biological sites, especially those where the two metals can cooperate to form an active centre. Catalytic properties of these polynuclear complexes, when studied, have been reported. Also some of the numerous heterodinuclear metal complexes that have been synthesized are here reviewed, included several crystal structures. 相似文献
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Johann W. Buchler Frank M. Künzel Uwe Mayer Michaela Nawra 《Fresenius' Journal of Analytical Chemistry》1994,348(5-6):371-376
Summary Gel electrophoresis is described as a new method for the characterisation of water-soluble tetraarylporphyrins and their metal complexes. The migration of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin, 5,10,15,20-tetrakis-(4-carboxyphenyl)porphyrin, 5,10,15,20-tetrakis(N-methyl-pyridinio)porphyrin, and of several of their complexes containing Zn, Cu, V, Ni, Ce, Mn, Mo, W, Re, Os and Ta ions has been studied. The separation of tri- and tetrasulphonated tetraphenylporphyrin or tri- and tetramethylated tetrapyridylporphyrin has been achieved. The behaviour of metal porphyrinates in water, e.g. axial hydration and formation of inner salts or ion pairs, can be studied by comparison of migration distances.Part 63: see [1] 相似文献
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The photoelectron spectra of several transition-metal carbonyl complexes of norbornadiene and mesitylene have been measured. The data for the norbordiene complexes have been compared with those reported previously for norbornadieneiron tricarbonyl. The shifts in energies of the π orbitals of the ligands introduced by the metal carbonyl moieties are remarkably insensitive to the choice o0f transition metal or geometry of the complex. However, the characters of the metal d-orbital ionization bands are markedly affected by the choice of ligand. 相似文献
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《Comptes Rendus Chimie》2008,11(3):307-316
Iron and cobalt complexes are a new family of catalysts for ethylene oligomerization and polymerization. The extensive researches on bis(imino)pyridyl metal complexes have been carried out with the aim of synthesizing their derivatives and finding suitable reaction parameters for the optimum activity. Beyond the modification works of bis(imino)pyridyl metal complexes, several alternative models with similar coordination sphere have been developed in our group. This review article describes our experiences in innovating new models of iron and cobalt complexes as catalysts for ethylene oligomerization and polymerization. 相似文献
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Ahmed A. Mohamed 《Coordination chemistry reviews》2010,254(17-18):1918-1947
Coinage metals nitrogen chemistry has not been studied extensively until recently. The focus of this review is the base- and halide-free complexes of the monoanionic nitrogen ligands. This review describes how minor ligand modifications can result in a drastic change in the metal–metal interactions in multinuclear compounds. Crystal structures of these complexes show individual complexes, dimers, supramolecular columnar packing or more complex supramolecular aggregates. Bulky substituents on the ligands can prevent intermolecular metal–metal interactions or the formation of supramolecular architectures. The nuclearity and metal–metal interactions in these complexes are controlled by ligand steric and electronic factors and solvent of crystallization. Many classes of nitrogen ligand coordination compounds have given rise to advances in several fundamental and applied research aspects. Recent potential applications of nitrogen ligand complexes are highlighted particularly for those complexes included in this review. 相似文献
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辉光放电光谱法定量分析金属材料表面纳米级薄膜的研究 总被引:1,自引:0,他引:1
介绍了利用辉光放电光谱法分析金属材料表面的纳米级薄膜。通过优化辉光光源的放电参数,计算标准样品的溅射率。溅射率经校正后,建立各元素的标准工作曲线,从而形成了纳米级薄膜的定量表面分析方法。试验证明,此方法对膜厚的测定具有很好的准确度和精密度,可应用于多种金属材料表面纳米级薄膜的研究。 相似文献
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《Journal of Coordination Chemistry》2012,65(1-2):91-99
Abstract Fenske-Hall molecular orbital calculations on the complexes CpFe(CO)2(CX)+ (X = O, S, Se, and Te) have been used to quantify the nature of bonding between the CX ligands and the metal atom. In addition, conclusions have been reached about the reactivity of the complexes under both nucleophilic and electrophilic attack. The previously established trend of increasing metal—ligand bond strength as X changes from O to S to Se is demonstrated by our molecular orbital calculations, and found to extend to Te. The mechanism for nucleophilic attack, variously explained in the past by either charge control or orbital control, is quantitatively ascribed to orbital control only. The nature of electrophilic attack on these complexes is also found to begin with orbital control. 相似文献
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本文报道几种不对称类卟啉镉(Ⅱ)配合物的合成及其结构表征,并对其电子吸收光谱特性进行了研究。结果表明,这类配合物的0-0跃迁在λmax>690nm有一个允许跃迁的强吸收带,且随π电子数及取代基的不同有着明显差别;在强极性溶剂中,该类配合物可发生H聚集;将跃迁能量、振子强度等性质与取代基Hammett常数进行线性相关,揭示了取代基效应对0-0跃迁的影响规律。 相似文献
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设计合成一类与短波长(635~650nm)半导体激光器相匹配用于有机光盘的光存储介质的偶氮染料金属螯合物.测定了偶氮染料及其金属螯合物的紫外 可见光吸收光谱,采用分光光度法确定该金属螯合物的结构与组成,计算了它的稳定常数.差热热重分析显示该金属螯合物具有较好的热学性能,有望可作为光记录介质. 相似文献