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合成了一个结构新颖的二茂铁基苯甲酸铜的双核簇合物([(p-FcC6H4COO)2Cu(DMF)].2H2O.DMF)2,通过X射线单晶衍射分析、元素分析、IR光谱、UV光谱及循环伏安等手段对标题簇合物的结构和性质进行了测试和表征.在双核簇合物分子中,两个中心铜离子通过羧基桥连在一起,Cu-Cu的距离为0.264 2 nm,每个Cu(Ⅱ)与来自四个不同配体上的羧基氧原子以及一个来自于溶剂DMF的氧原子配位,形成一个涡轮双核簇合物.循环伏安表明,配位键的形成,对配体的氧化还原的性质影响很小. 相似文献
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本文测定了新型层状混合金属簇合物(a)Fe2Mo2Te4和(b)Fe2Ta2Te4的穆斯堡尔谱。由穆斯堡尔参数确定这两个簇合物的Fe原子都属高自旋+3价,处四面体配位中心。簇合物(a)中两个铁原子是等价的,而簇合物(b)中两铁原子却是不等价的,这是由于簇合物(b)中Fe1原子的构型畸变比Fe1原子大的缘故。 相似文献
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设计合成了两类具有π共轭骨架的Salen-卟啉型配体及金属配合物. 以Salen-卟啉半体及相应的醛为原料, 运用金属模板法合成了单核镍和双核镍Salen-卟啉型金属配合物. 在单核镍的基础上可得到异双核镍、锌Salen-卟啉型金属配合物. 通过核磁共振氢谱(1H NMR)、紫外-可见(UV-Vis)光谱、傅里叶变换红外(FTIR)光谱、电喷雾质谱(ESI-MS)和荧光光谱等多种谱学手段对其结构进行了表征. 研究表明, 单核镍及异双核镍、锌配合物中, 镍离子落入Salen 部分的配位空腔, 而锌离子则是与卟啉部分形成锌卟啉大环结构。由于卟啉环流效应及分子π共轭结构的影响, 导致配体上的氢原子的化学位移向高场或低场移动. 当金属离子与配体配位之后,卟啉部分的紫外-可见光谱的Soret带和Q带均发生显著变化, 而荧光则出现猝灭现象. 相似文献
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双核大环配合物在模拟金属蛋白活化中心,键合活化小分子及作为双功能催化剂方面具有广阔应用前景。本文就西夫碱型,串连型,具有“软”“硬”空腔的单大环,双大环及大多环双核配合及其配合物的性质和它们仿生方面的研究进展进行综述报道。 相似文献
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合成了四个新型的手性双核(R,R)Salen配合物[(Cu)2L•H2O(2), (Ni)2L(3), (Zn)2L•H2O(4), (MnCl)2L•2H2O(5)], (其中L是由(R,R)环己二胺、 3,5-叔丁基水杨醛、 5,5’-亚甲基二水杨醛为原料合成的手性二聚Salen配体(1)).用元素分析、NMR、FT-IR、UV-Vis、CD光谱对配体和配合物进行了表征.在与单核的Salen配体和配合物比较的基础上,详细讨论了红外光谱、电子吸收光谱、圆二色光谱性质.发现双核配体和配合物的电子吸收光谱吸收峰的位置和形状与单核的配体和配合物基本一致,而吸收峰的强度有近似两倍的关系.另外, 用激子偶合理论解释了此类手性化合物圆二色谱的Cotton效应和Cotton分裂. Cotton分裂的方向依赖于环己二胺的构象.(R,R)环己二胺决定了Salen化合物的手征性为负, Cotton分裂的正负两部分分别处于高能区和低能区. 相似文献
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本文报道一个新的三核钼原子簇化合物在室温和77K固态和液态的EPR谱,这些谱均呈现出a,b两套谱线的叠加,分析谱线的强度比,线宽和谱参数,认为g值较大的a谱归属于三核钼原子簇化合物,而b谱归属于单核钼杂质。从由X射线晶体结构方法确定的空间结构出发,三核钼原子簇化合物可能有两种分子形式:Mo3(μ3-S)(μ2-S)3Cl[S2P(OEt)2]4 1Mo3(μ3-S)(μ2-S)(μ2-Cl)2Cl[S2P(OEt)2]4 2分别用简单量子化学理论和EHMO法计算出未配对电子所处的分子轨道,求出g1和g1,并与EPR实验值相比较,认为该化合物的分子式应为2,簇骼{Mo3}属七电子体系,在77K温度下,其未配对电子主要局域在三个钼原子所组成的近似等腰三角形簇骼的顶点钼原子周围。 相似文献
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《Journal of Coordination Chemistry》2012,65(1):67-72
Abstract The binuclear copper(II) complex [Cu2(dien)2(NCS)2](ClO4)2, where dien = diethylenetriamine, has been synthesized and characterized by analysis, infrared (IR) and electron paramagnetic resonance (EPR) spectra. A centrosymmetric axial‐equatorial 1,3-μ-NCS bridged binuclear copper(II) complex has been identified by X-ray diffraction, in which each copper(II) is five-coordinated with an elongated square pyramidal geometry with four nitrogen atoms on its basal plane and one sulfur atom at the apical position. Frozen solution EPR spectra at 77 K indicate that the interaction between the two copper centers is weak and the bridge is retained in solution. 相似文献
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Complex systems of paramagnetic centres existing in demineralised flame coal (71.4 wt% C), medium-rank coal (85.6 wt% C) and
anthracite (94.9 wt% C) were analysed by electron paramagnetic resonance spectroscopy (EPR). Different groups of paramagnetic
centres were searched in macerals (exinite, vitrinite, inertinite) of coals with carbon contents of 73.8 wt% C and 85.6 wt%
C. Experimental EPR spectra were fitted by different superposition of theoretical lines. Total concentration of paramagnetic
centres both in coal and macerals increases with carbon content in the sample. Total concentration of paramagnetic centres
in macerals increases from exinite to inertinite. Four groups of paramagnetic centres were found in medium-rank coal, and
only two groups exist in flame coal and anthracite. The EPR spectrum of medium-rank coal is a superposition of two broad and
two narrow lines. Both broad and narrow, and two narrow lines were measured in EPR spectra of flame coal and anthracite, respectively.
Two types of paramagnetic centres with broad lines and one group with narrow lines exist in exinite and vitrinite from medium-rank
coal. Two narrow components were observed in EPR spectra of its inertinite. Two different broad electron paramagnetic resonance
signals were detected for macerals from low-coalificated coal. Paramagnetic centres systems of medium-rank coal samples reveal
the most complex character. Broad EPR lines were not observed for the higher coalificated samples, i.e., anthracite and inertinite
from medium-rank coal. Narrow lines do not occur in EPR spectra of low-coalificated macerals. Strong dipolar interactions
and fast spin-lattice relaxation processes are characteristic for paramagnetic centres with broad lines. Strong exchange interactions
and short spin-lattice relaxation time were measured for paramagnetic centres with the narrowest EPR signals. 相似文献
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SimLabel: a graphical user interface to simulate continuous wave EPR spectra from site‐directed spin labeling experiments 下载免费PDF全文
E. Etienne N. Le Breton M. Martinho E. Mileo V. Belle 《Magnetic resonance in chemistry : MRC》2017,55(8):714-719
Site‐directed spin labeling (SDSL) combined with continuous wave electron paramagnetic resonance (cw EPR) spectroscopy is a powerful technique to reveal, at the residue level, structural transitions in proteins. SDSL‐EPR is based on the selective grafting of a paramagnetic label on the protein under study, followed by cw EPR analysis. To extract valuable quantitative information from SDSL‐EPR spectra and thus give reliable interpretation on biological system dynamics, numerical simulations of the spectra are required. Such spectral simulations can be carried out by coding in MATLAB using functions from the EasySpin toolbox. For non‐expert users of MATLAB, this could be a complex task or even impede the use of such simulation tool. We developed a graphical user interface called SimLabel dedicated to run cw EPR spectra simulations particularly coming from SDSL‐EPR experiments. Simlabel provides an intuitive way to visualize, simulate, and fit such cw EPR spectra. An example of SDSL‐EPR spectra simulation concerning the study of an intrinsically disordered region undergoing a local induced folding is described and discussed. We believe that this new tool will help the users to rapidly obtain reliable simulated spectra and hence facilitate the interpretation of their results. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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《Journal of Molecular Structure》2004,689(3):191-197
Bis[ethyl (trifluoroacetyl)acetato]copper(II), [Cu(etfac)2], has been prepared and studied by X-ray crystallography and EPR spectroscopy. The complex is centrosymmetrical and crystallizes in the P21/c space group with two formula units per unit cell. After dissolving of the complex in solid matrix or in suitable solvents some changes are detected in the EPR spectra and are discussed. The EPR spectra of the complex magnetically diluted in the corresponding Pd(II) complex reveal the presence of only one paramagnetic species further denoted as B. However, EPR spectra measured in solution indicate the presence of two different paramagnetic species: (i) non-distorted parent species B, and (ii) rhombic-distorted species A, which prevail in solutions. The A:B species ratio is a function of the solvent and temperature. The [Cu(etfac)2] adduct with 4-(dimethylamino)pyridine has also been studied and found to crystallize in the C2/c space group. The adduct EPR spectrum monitored in solution shows the presence of only one paramagnetic species. 相似文献
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Velavan K Venkatesan R Sambasiva Rao P 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,62(1-3):494-499
Single crystal EPR studies on Cu(II) doped paramagnetic host lattices, hexaimidazole M(II) dichloride tetrahydrate (M=Co and Ni), isomorphous with M=Zn, have been carried out from room temperature to 77K to understand the nature of Jahn-Teller (JT) distortion in these paramagnetic host systems. The paramagnetic impurity, doped in the present two paramagnetic host lattices, shows anisotropic EPR spectra with superhyperfine from ligands, even at room temperature. An interesting observation noticed in the EPR spectra at room temperature is that there are more resonances corresponding to the second site in the paramagnetic hosts than in the diamagnetic host at 4.2K. This difference in behavior between the diamagnetic and paramagnetic host lattices indicates a change in the depth of the JT valleys. The spin Hamiltonian parameters are evaluated for Cu(II) ion in both the host lattices and the relaxation times have been calculated for the ion in cobalt host lattice only. 相似文献
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E. G. Boguslavskii S. A. Prokhorova V. A. Nadolinnyi 《Journal of Structural Chemistry》2005,46(6):1014-1022
The procedure for calculating the orientation distribution of molecules using the angular dependence of EPR spectra was employed to study copper(II) phthalocyanine (CuPc) films varying in thickness and obtained by depositing the molecular complex on flat quartz plates. At the first stage of deposition, a layer of the α-CuPc phase with preferable orientation of molecular stacks along the plate surface is formed. At the second stage, a layer with an orthogonal arrangement of molecular stacks is condensed over the first layer. The interaction with NO2 forms CuPc binuclear associates. Analysis of the EPR spectra made it possible to determine the symmetry of the structure and the distance between the paramagnetic Cu2+ ions; the structure of the associates has been proposed. The orientation distribution of CuPc dimers in the film depends both on the initial ordering in the film and on processing conditions. Strong disordering of molecular stacks in ordered films during the α-CuPc to α-CuPc phase transition has been found. 相似文献
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The structure and EPR spectra of binuclear copper(II) complexes with acyldihydrazones of β-diketones
G. M. Larin V. F. Shul’gin E. D. Mel’nikova V. Ya. Zub A. N. Chernega 《Russian Chemical Bulletin》2009,58(7):1342-1348
The synthesis and structure of binuclear copper(II) complexes with acyldihydrazones of some β-diketones are described. The molecular structure of the copper(II) complex [Cu2L·4Py] with trifluoroacetylacetone succinyldihydrazone (H4L) was determined by the single-crystal X-ray analysis. Central atoms are bridged by a chain of seven σ-bonds with a Cu...Cu distance of 8.750 Å. EPR spectra of copper(II) complexes with acyldihydrazones of trifluoroacetylacetone and lower dicarboxylic acids containing from one to four methylene groups in the aliphatic spacer show the seven-line HFS due to spin-spin coupling of unpaired electrons with the two equivalent copper nuclei (g = 2.110, a = (38.5–40.5)⊙10?4 cm?1). By extending polymethylene spacer, as well as by modifying starting β-diketone, an exchange interaction between paramagnetic centers is suppressed. 相似文献
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Experimental chitin-uranium-copper EPR spectra have been simulated by computer. The simulation suggests that the chitin-copper-uranium EPR spectra are primarily due to a chitin-copper interaction, with insignificant contribution from other paramagnetic species. The simulation suggests two possible complex configurations, both involving one ligand nitrogen atom. 相似文献
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J. Kuruc 《Journal of Radioanalytical and Nuclear Chemistry》1991,154(1):61-72
EPR spectra of paramagnetic centers originating from X-ray-irradiation of aluminium hydroxide at room temperature have been measured. The EPR spectrum represents a superposition of EPR spectra of ionic centers O–, holes of type and trapped electrons. Radiation chemical yield of paramagnetic centers observed at room temperature (293 K) is G(spins.)=4.4±0.6) spins per 100 eV absorbed energy. The decay of paramagnetic centers in irradiated Al(OH)3 was oberved at 293 K. The rate constant of the paramagnetic centers decay in irradiated Al(OH)3 is K2=(0.0980±0.0019) kg·mol–1·min–1 and their half-life is 9.43±0.18 days.Dedicated to the memory of the late Genrikh Markovis Kolyiari. 相似文献
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The two bis-macrocycles 4 and 5 in which the tetraaza units are separated by a chain of different length, have been synthesized using 1,4,7-tritosyl-1,4,7,11-tetraazacyclotetradecane as starting compound and bifunctional alkylating agents. The bis-macrocycles give binuclear complexes with Ni2+ and Cu2+, the properties of which have been studied to obtain information about the interaction of the two subunits as a function of the distance. The VIS spectra of the Ni2+ and Cu2+ complexes indicate that both metal ions are in a square-planar geometry as expected from the results of the analogous complexes with 1,4,7,11-tetraazacyclotetradecane 7 . Cyclic voltammetry and differential pulse polarography of the binuclear Ni2+complexes in CH3CN show a single two-electron step for ligand 5 , whereas two distinct one-electron redox processes can be observed for ligand 4 , indicating that the two metal ions interact with each other when the chain length is shorter. Similarly, the EPR studies of frozen solutions of the binuclear Cu2+ complexes clearly show that a magnetic dipolar interaction between the two paramagnetic centers exists, and that the strength of it depends upon the length of the bridge. Finally, from the X-ray structures of the binuclear Ni2+ complexes with 4 and 5 , it is seen that the two rings are kept apart as far as possible, the distances between the two metal ions determined in the solid correlate well with the observations in solution. 相似文献