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1.
本文采用简化一般价力场对3-(9-药甲氧基羰基)-四氢噻唑-2-疏酮(简称Fmoc-TTT)分子的振动光谱做了简正坐标分析计算,得到了一套合理的精化力常数。并对Fmoc-TTT分子的振动频率进行了指认。其计算频率与实验频率的平均百分误差为0.691。  相似文献   

2.
两种新型对称卟啉的合成及紫外可见光谱特性研究   总被引:5,自引:0,他引:5  
本文采用一种新型的合成方法合成了两种新型对称卟啉meso-四(对苯甲酰胺基苯基)卟啉和meso-四(邻苯甲酰胺基苯基)卟啉,用元素分析,红外光谱,核磁共振谱对两种卟啉进行了表征,并对其紫外可见光谱特性进行了研究。  相似文献   

3.
利用Guassian94程序和QCISD/6-311++G方法得到He-HF和He-FH两种线性平衡结构,计算出了这两种弱结合分子的结构参数、离解能和二阶力常数。在此基础上,利用多体项展式方法民出He-HF(X^1Σ^+)体系的分析势能函数,得到的势能面准确地再现了He-HF和He-FH两种线性结构。  相似文献   

4.
研究了15-冠-5(15-C-5)与Na2[Pd(SCN)4]的反应,得到的配合物[Na(15-C-5)]2[Pd(SCN)4]通过元素分析、红外光谱、单晶X射线衍射进行了结构分析.该配合物为单斜晶系,空间群C2/c,晶体学数据: a=1.3525(6)nm,b=1.3729(6)nm,c=2.0312(9)nm,β=102.985(6)°,V=3.675(3)nm3,Z=4,F(000)=1696,R1=0.0288,wR2=0.0457.结构分析表明,该配合物由两个[Na(15-C-5)]+配阳离子和一个[Pd(SCN)4]2-配阴离子组成,二者通过Na-N相互作用形成二维网状结构.  相似文献   

5.
采用密度泛函理论中的广义梯度近似对C60(CF3nn=2,4,6,10)几何结构和电子性质的变化规律进行了计算研究.发现在C60(CF34可能稳定存在的三种同分异构体中,具有p p p加成方式的衍生物热力学性质最为稳定;在C60(CF36可能稳定存在的三种同分异构体中,具有p p p m p加成方式的衍生物热力学性质最为稳定.对C60(CF32,C60(CF34,C60(CF36和C60(CF310四种加成衍生物的几何结构分析可知:随着CF3加成个数的增加,C60中的C—C平均键长逐渐变大,笼子与CF3之间连接键CC60—CCF3逐渐变大.对它们的电子结构分析可知,随着CF3加成数目的增多,反应热几乎是线性增加.而C60(CF3nn=2,4,6,10)分子的平均反应热在n=6处为极大值,说明C60(CF36应该是最容易得到的加成产物.由Mulliken电荷可知,加成的CF3个数越多,CF3与笼子的相互作用也就越强,每个CF3转移到笼子上电荷数也就越多.C60(CF3n的自旋聚居数分布表明它们均为闭壳层结构.最后,从CF3对分子的前线轨道贡献可知,四种分子的得电子情况和失电子情况均发生在碳笼本身,并不随着CF3个数的增加而发生明显的改变. 关键词: 60(CF3nn=2')" href="#">C60(CF3nn=2 10) 几何结构和电子性质 密度泛函  相似文献   

6.
何国芳 《光谱实验室》2003,20(5):716-718
合成了配合物 { [K(18- C- 6 ) ][K(H2 O) 2 ]} [Cd(CN) 4 ](1) ,并通过元素分析、红外光谱、单晶 X-射线衍射进行了结构分析。配合物属单斜晶系 ,空间群 P2 (1) / n。晶体学数据 :a=0 .936 5 3(18) nm,b=1.6 178(3) nm,c=1.74 81(3) nm,β=91.332 (3)°,V=2 .6 479(9) nm3 ,Z=4 ,Dcalcd=1.4 5 3g/ cm3 ,F(0 0 0 ) =12 0 8,R1=0 .0 317,w R2 =0 .0 5 6 7。配合物中 [K(18- C- 6 ) ],[K(H2 O) 2 ]和 [Cd(CN) 4 ]基团通过 K N键和 K —π相互作用形成三维网状结构  相似文献   

7.
本文主要介绍了双层类钙钛矿锰氧化物La1.4Ca1.6Mn2O7及其掺杂样品不同的制备工艺,分析了它们的XRD和R-T图像,讨论了制备方法对材料结构以及电磁性能的影响。  相似文献   

8.
研究了18-冠-6与Na2[Cu(i-mnt)2][i-mnt=异丁二腈烯二硫醇阴离子,S2CC(CN)2-2]的反应,得到的配合物[Na(18-C-6)]2[Cu(i-mnt)2](1)通过元素分析、红外光谱、X射线单晶衍射进行了结构分析.配合物为单斜晶系,空间群P2(1)/c.晶体学结构数据a=1.2819(11),b=1.1793(10),c=1.4928(13)nm,β=99.121(16)°,V=2.228(3)nm3,Z=2,Dcaled.=1.369g/cm3,F(000)=958,R1=0.0521,wR2=0.1003.1中的[Cu(i-mnt)2]基团通过配体i-mnt的氮原子与两个[Na(18-C-6)]基团中的钠原子成键,形成稳定的中性配合物.  相似文献   

9.
实验研究了La0.5Sr0.5MnO3体系La位上Y掺杂对电荷有序相的影响。结果表明掺杂量为0.15以下时,样品均呈现金属—绝缘体转变行为;当掺杂量为0.2,0.25时样品中出现了电荷有序相,通过对样品的结构和输运特性的仔细研究,发现有三种因素对其输运特性具有重要影响:带宽即<rA>,eg电子的轨道,无序度δ^2,同时,实验结果表明电荷有序相的形成是因为电子之间的强关联作用的结果。  相似文献   

10.
研究了二苯并18-冠-6(DB18-C-6)与(NH4)2[Pd(SCN)4]的反应,通过元素分析、红外光谱、单晶X射线衍射对生成的配合物[NH4(DB18-C-6)]2[Pd(SCN)4](1)进行了结构分析.1为三斜晶系,空间群P-1,晶体学数据:a=0.8705(3)nm,b=1.1954(4)nm,c=1.3044(4)nm,α=73.216(5)°,β=78.897(5)°,γ=81.105(6)°,V=1.2682(7)nm3,Z=1,F(000)=568,R1=0.0301,wR2=0.0431.配合物由二个[NH4(DB18-C-6)]+配阳离子和一个[Pd(SCN)4]2-配阴离子组成,二者通过N-H…N氢键形成中性配合物,配合物中不存在阳离子-π相互作用.  相似文献   

11.
The local structure and the valences of europium in SrBPO5:Eu prepared in air were checked by means of XAFS at Eu-L3 edge. From the EXAFS results, it was discovered that the doped europium atoms were nine-coordinated by oxygen atoms and the distances of bond Eu-O were 2.42 Å in the host. From the XANES data, it was found that the divalent and trivalent europium coexisted in the matrix. The emission spectra excited by VUV or UV exhibited a prominent broad band due to the 4f65d-4f7 transition of Eu2+ ions, which indicated that the trivalent europium ions were reduced in air in the matrix at high temperature by the defects [VSr]″ formed by aliovalent substitution between Sr2+ and Eu3+ ions. The VUV excitation spectra in 100-200 nm range showed that the matrix had absorption bands with the maxima at about 130 and 150 nm, respectively.  相似文献   

12.
By means of the Backlund transformation, a quite general variable separation solution of the (2 1)-dimensional Maccari systems is derived. In addition to some types of the usual localized excitations such as dromion,lumps, ring soliton and oscillated dromion, breathers solution, fractal-dromion, fractal-lump and chaotic soliton structurescan be easily constructed by selecting the arbitrary functions appropriately, a new novel class of coherent localizedstructures like peakon solution and compacton solution of this new system are found by selecting aperopriate functions.  相似文献   

13.
By means of the Baecklund transformation, a quite general variable separation solution of the (2 1)-dimensional Maccari systems is derived. In addition to some types of the usual localized excitations such as dromion, lumps, ring soliton and oscillated dromion, breathers solution, fractal-dromion, fractal-lump and chaotic soliton structures can be easily constructed by selecting the arbitrary functions appropriately, a new novel class of coherent localized structures like peakon solution and compacton solution of this new system are found by selecting apfropriate functions.  相似文献   

14.
This study reports the simple synthesis of MFe2O4 (where M=Zn, Mn and Co) nanostructures by a thermal treatment method, followed by calcination at various temperatures from 723 to 873 K. Poly(vinyl pyrrolidon) (PVP) was used as a capping agent to stabilize the particles and prevent them from agglomeration. The pyrolytic behaviors of the polymeric precursor were analyzed by use of simultaneous thermo-gravimetry analyses (TGA) and derivative thermo-gravimetry (DTG) analyses. The characterization studies were conducted by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Fourier transform infrared spectroscopy (FT-IR) confirmed the presence of metal oxide bands for all the calcined samples. Magnetic properties were demonstrated by a vibrating sample magnetometer (VSM), which displayed that the calcined samples exhibited different types of magnetic behavior. The present study also substantiated that magnetic properties of ferrite nanoparticles prepared by the thermal treatment method, from viewing microstructures of them, can be explained as the results of the two important factors: cation distribution and impurity phase of α-Fe2O3. These two factors are subcategory of the preparation method which is related to macrostructure of ferrite. Electron paramagnetic resonance (EPR) spectroscopy showed the existence of unpaired electrons ZnFe2O4 and MnFe2O4 nanoparticles while it did not exhibit resonance signal for CoFe2O4 nanoparticles.  相似文献   

15.
蒽类荧光染料的荧光性质及其化学发光效应   总被引:5,自引:1,他引:4  
本文报道了蒽中位取代的荧光染料(9,10-二苯基蒽,9,10-二苯乙炔基蒽)的合成。分析测试了这类染料的液相荧光和化学发光光谱,讨论了它们的结构与其荧光和化学发光波长及效率的关系(在双乙二酸酯化学发光体系中),并配制了发光明亮的高效化学发光液。  相似文献   

16.
The conformations of three analogues of baclofen 1: phaclofen, saclofen, and hydroxy-saclofen 2–4, potent GABAB antagonists, in solution (D2O) are estimated from high-resolution (300 MHz) H NMR coupling data. Conformations and populations of conformers are calculated by means of a modified Karplus-like relationship for the vicinal coupling constants. H NMR spectral analysis evidences how 1–3 keep in solution the preferred a conformation around C3-C4 bond. A partial rotation is set up around C2–C3 bond (the conformations about C2–C3 are all highly populated in solution) particularly for 2 and 3 while 1 shows a relative preferred a conformation. This evidences the influence of the anionic moiety.  相似文献   

17.
Thin films of CdTe have been deposited onto stainless steel and fluorine-doped tin oxide (FTO)-coated glass substrates from aqueous acidic bath using electrodeposition technique. The different preparative parameters, such as deposition time, bath temperature and pH of the bath have been optimized by photoelectrochemical (PEC) technique to get good quality photosensitive material. The deposited films are annealed at different temperature in presence of air. Annealing temperature is also optimized by PEC technique. The film annealed at 200 °C showed maximum photosensitivity. Different techniques have been used to characterize as deposited and also as annealed (at 200 °C) CdTe thin film. The X-ray diffraction (XRD) analysis showed the polycrystalline nature, and a significant increase in the XRD peak intensities is observed for the CdTe films after annealing. Optical absorption shows the presence of direct transition with band gap energy 1.64 eV and after annealing it decreases to 1.50 eV. Energy dispersive analysis by X-ray (EDAX) study for the as-deposited and annealed films showed nearly stoichiometric compound formation. Scanning electron microscopy (SEM) reveals that spherically shaped grains are more uniformly distributed over the surface of the substrate for the CdTe film.  相似文献   

18.
13C NMR and 2D (H,H and H,C COSY) spectra of selected examples of sugar (5H-1,2,4-triazino[5,6-b]-indol-3-yl) hydrazones, peracetylated sugar-1-acetyl -1- (5-acetyl-1,2,4-triazino[5,6-b]indol-3-yl)hydrazones, and 10-acetyl-3-(per-0-acetylalditol-1-yl)-1,2,4-triazolo[4′, 3′:2,3][1,2,4]triazino[5,6-b]indole have been reported. The conformation of the latter C-nucleoside analogues have been determined by analysis of their 1H NMR spectra. The D-galacto, D-manno and L-arabino isomers are preponderantly existing in the planar zigzag arrangement of carbon atoms.  相似文献   

19.
Pure, urea and thiourea doped hippuric acid (HA) single crystals have been grown in acetone using slow evaporation technique at a constant temperature, with the vision to improve the properties of the crystals. The crystal systems and the unit cell parameters of the grown crystals were identified from single crystal X-ray diffraction. The crystalline nature of the grown crystals was confirmed by powder X-ray diffraction and the diffraction peaks were indexed. The variations in composition due to the addition of dopants were identified by CHNS analysis. FT-IR studies reveal the presence of different vibrational bands. The optical characteristics were assessed by UV–vis analysis and it indicates the transmission in the visible region. TGA and DSC studies indicate the thermal behavior of pure and doped crystals. The Second Harmonic Generation (SHG) has been tested using Kurtz Powder Technique for the pure and doped crystals. It is found that the thiourea doped hippuric acid crystals have SHG efficiency of 2.08 times higher than that of potassium dihydrogen phosphate (KDP) single crystal. The dielectric studies were carried out, and the variations of dielectric constant and dielectric loss with temperature have been studied.  相似文献   

20.
研究了铕 ( ) - 5 - Br- PADAP- CTMAB体系的显色反应和光度性质 ,并探讨了其最佳的光度分析条件。在 p H =5 .0的 HAc- Na Ac缓冲溶液中 ,有表面活性剂 CTMAB存在的条件下 ,Eu( )与 5 - Br-PADAP形成了配位比为 1∶ 2的深红色络合物。配合物的最大吸收峰位于 5 98nm,表观摩尔吸光系数为1.5 9× 10 5L· mol-1· cm-1,铕含量在 0— 10μg/ 2 5 m L范围内符合比耳定律。加标回收实验结果令人满意。  相似文献   

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