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1.
氯化二氯代四苯基叶啉磷(Dichloro(5,10,15,20-tetraphenylporphinato)-phosphorus(V)chloride,[PCl2TPP]Cl)是典型的非金属卟琳配合物.据文献报导[1]该配合物能够与噻吩类化合物反应,所得单体经电解氧化,可生成具有导电性的聚合物.因此,测定[PCl2TPP]Cl的分子结构有着十分重要的意义.1标题化合物的制备及单晶生长标题化合物技文献[2]合成.用于X-射线衍射的单晶样品是将标题化合物的二氯甲烷/正庚烷混合溶液静置数周后得到的.单晶为紫色,用于X-射线衍射测定的晶粒尺寸为0.38mm×0.38mm×0.28mm.…  相似文献   

2.
本文报道利用循环伏安法和紫外可见光谱法测定了过渡金属钼、镧系元素铕和铒与N、N-二乙基二硫代氨基甲酸根(dtc)构成的八配位离子对配合物:[Mo(dtc)4][Eu(dtc)4]和[Mo(dtc)4][Er(dtc)4]的氧化还原特性和光谱性质。实验证实,配合物的配正离子[Mo(dtc)4+比配负离子[Eu(dtc)4-和[Er  相似文献   

3.
由于钢作为活性配位中心离子,存在干具有生物功能的蛋白质大分子中,近年来钢的配位化学受到广泛关注.普遍认为,咪唤基在铜蛋白的配位化学中起重要作用*,开展钢与具咪陵基配体所形成配合物的研究,有助于揭示钢在蛋白质中的生物化学功能及其与咪哩基等其它基团相互键合作用的本质.我们曾报导了四种新型具苯并咪吐基双核CIJ()配合物:[CllZ’(OCTB)flC104h·1.SHZO川,[Cll。’(NMOCTB)]·(CIO。)。·H。O(2),[Cll。’(NBUOCTB)](CIO。)z切,[Cll。’(NBOCTB)]·(CIO4h·H。O(4)的合…  相似文献   

4.
氧化物、盐类在氧化物载体表面的自发分散是一种广泛存在的现象,文献中已报导过大量氧化物和盐类在高比表面载体上分散的研究结果['-3]TIO。作为一种较新型的载体,与Y-AI。O。、硅胶等传统载体相比,有许多不同特性.活性组分在TIO。表面的分散状态及所得催化剂的性能已有不少报导['-'],但所用的TIOZ主要是较高比表面的锐钛矿型TIOZ(刘金红石型TIO。(r)和锐钛矿型TIOZ(a)的结构不同,它是高温生成相,比表面较小['].氧化物在金红石上的分散行为仍未见报导.我们制备了三种具有不同比表面的TIO水),系统地研…  相似文献   

5.
合成了希土高氯酸盐开环冠醚二缩乙二醇(EO2)晶体,(Ln=Nd,Ho),测定了结构,文内以Nd-L的数据为主要研究对象(方括号内是Ho-L的数据)。晶体属单斜晶系,P21/n空间群,化学式[Ln(EO2)3](ClO4)3·3H2O,晶胞参数为:a=14.124(1)[14.087],b=13.990(1)[14.039],c=15.265(1)[15.014];β=95.78(1)[95.64]°;V=3001.1(6)[2955]3;Mr=815.01[835.70];Z=4;Dc=1.804[1.865]g/cm3;石墨单色器,μ(MoKα)=2.09[3.07]mm-1,最终偏离因子R=0.055[0.074],RW=0.071[0.109]。研究结果表明晶体具有相同的结构,配位多面体为九配位三帽三棱柱。发现EO2醚链有绕C-C键呈STTS分布的规律。弱配体高氯酸根不参加配位。  相似文献   

6.
利用CNDO/2近似方法对25,26,27,28-四羟基杯[4]芳烃的四种不同构象的平衡几何构型以及所有可能发生的构象间转换的势垒能量进行了计算.在此基础上提出了合理的杯[4]芳烃的构象间转换机理,指出部分锥形构象是必经途径.利用该机理可以圆满地解释某些实验现象.  相似文献   

7.
{Co[(OR)。Co(NRa]a}(SO。如的水合物前人早已制得I’],其中的二齿配住有Co-0四元环存在问,易于通过复分解反应转化为这个系统的钻氨配体物,有光学活性问,与细菌、a淀粉一起培养可导致淀粉钝化.网.对这种固体配合物的热分解研究有助于了解其固态的配体取代反应.本文报导了该化合物粉未X射线衍射和热分牲的初步研究结果.1实验技文献门制备了标题化合物.产物在空气中干燥,以本为介质,用比重并法测定其密度.用Perldn-Elmer683型红外光谱仪,KBr压片法作IR谱.用(日)岛津XD-3A衍射仪(带石墨单色器),CuKa…  相似文献   

8.
金属和半导体纳米粒子的制备及性质的研究是当今材料科学和物理化学的热门课题[1-6].在利用太阳能光降解环境污染物、生物传感器以及光生物等方面这些纳米粒子都具有实际应用的可能性.对纳米粒子表面进行修饰而形成的复合纳米粒子可以有效地调整单一颗粒的表面性质甚至颗粒的稳定性.另外,复合纳米粒子的制备对研究纳米粒子的尺寸量子化效应、非线性光学性质及其它光电性质都有重要的意义.人们已成功地制备了许多复合金属-金属纳米粒子,如Cu-Ag[7],Ag-Pd[8]及Ag-Pt[9]等.关于复合半导体-半导作纳米粒子也有报导,如C…  相似文献   

9.
十二氢十二硼酸双[π-芳烃-π-环戊二烯基铁]的紫外-可见光谱及Mossbauer参数胡培植,季立才,孙绍发,张伦(武汉大学化学系,武汉430072)祁守仁(华中师范大学物理系,武汉430070)作者先前合成了一系列闭式十二氢十二硼酸双[π-芳烃-π...  相似文献   

10.
合成了14个新化合物:1-酰氧(胺)基-2,8,9-三氧杂-5-氮杂-1-锡杂三环[3.3.3.01.5]十一烷.由IR、1HNMR、13CNMR和119SnNMR及元素分析确定其结构.该类化合物在CDCl3中可能形成六配位化合物,而在DMSO中,溶剂分子参与Sn原子配位,聚合体解聚为六配位化合物.  相似文献   

11.
ZrO2表面B2O3的分散及其作用状态   总被引:4,自引:0,他引:4  
用XPS、FT IR和FT Raman等技术研究了ZrO2表面B2O3的分散及其作用状态,测定了B2O3在ZrO2表面的分散阈值.结果表明:B2O3在ZrO2表面可以三配位BO3和四配位BO4结构单元存在;载体ZrO2的预焙烧温度和硼含量对B2O3的分散及作用状态有较大影响,并改变BO3与BO4结构单元之间的比例.实验测得B2O3在ZrO2载体上的单层分散阈值为0.05 gB2O3/gZrO2(或B2O3的质量分数w=4.76%),处在此单层中的硼原子以BO4为结构单元直接与ZrO2表面相作用.只有当B2O3的负载量超过此(单层)分散阈值时, BO3结构单元才会形成.  相似文献   

12.
Infrared and polarized single crystal Raman spectra of lithium triborate (LBO; LiB3O5) are reported and analysed. All four (A1, A2, B1 and B2) symmetry species of the C2v, point group isomorphic to the C2v9(Pna21) space group are Raman active in distinct crystal polarization experiments. A complete set of symmetry assignments based on a factor group analysis is presented. The internal and external vibrations are separated on the basis of frequency and the observation that the magnitude of the correlation splitting for the internal modes is very small. A comparison of the internal frequencies of various borate species suggests a correlation between the B-O stretching frequency and the nonlinear optical efficiency of the material.  相似文献   

13.
A new scheme for deriving localized basis orbitals (LBOs) and for obtaining integral transformations from the basis orbitals (BOs) to the LBOs has been introduced. The scheme was tested at the ab initio Hartree-Fock level using the STO-3G basis set. It has been revealed that it provides results that are close to the conventional ab initio approximations for various physical-chemical properties. At the same time, both the number of differential overlaps and the number of electron repulsion integrals (ERIs) grow with the system size notably slower than those calculated for the usual BOs. The power exponent for ERI/LBO is typically smaller by 0.3-0.6 than that for ERI/BO. The exponent reaches the value of 1.69 even for triglycine (24 atoms only), which represents a relatively small molecular model. Thus, the localization of the BOs (using LBOs) may result in additional improvements in efficiency even for electronically delocalized systems. It was shown that ERI/LBO is particularly efficient for systems with complex spatial structures (including conjugated species). The obtained results indicate that the proposed scheme could be included in computational methods targeted at calculating large molecular systems (which achieve linear scaling for more distant interactions). Neglecting ERI/LBO does not depend on the delocalization of the localized MO using ERI/LBO. The orthogonality and locality of the LBOs should make them useful in methods based on dividing the system into orthogonal subsystems.  相似文献   

14.
A Raman study of 3-methyl-4-nitropyridine-N-oxide single crystal (3M4NPO) has been performed at 78 K in the range 10–3500 cm−1. The symmetry analysis of the vibrational modes of 3M4NPO is given. The assignments are presented for internal and external modes. The results of the Raman spectra exhibit the spectroscopic proofs of hydrogen bonds in the crystal.  相似文献   

15.
ZrO_2表面 B_2O_3的分散及其作用状态   总被引:1,自引:0,他引:1  
用 XPS、 FT IR和 FT Raman等技术研究了 ZrO2表面 B2O3的分散及其作用状态,测定了 B2O3在 ZrO2表面的分散阈值 .结果表明: B2O3在 ZrO2表面可以三配位 BO3和四配位 BO4结构单元存在;载体 ZrO2的预焙烧温度和硼含量对 B2O3的分散及作用状态有较大影响,并改变 BO3与 BO4结构单元之间的比例 .实验测得 B2O3在 ZrO2载体上的单层分散阈值为 0.05 gB2O3/gZrO2(或 B2O3的质量分数 w=4.76%),处在此单层中的硼原子以 BO4为结构单元直接与 ZrO2表面相作用 .只有当 B2O3的负载量超过此(单层)分散阈值时, BO3结构单元才会形成 .  相似文献   

16.
Fourier transform polarized IR and Raman spectra of bis(guanidine) zirconium bis(nitrilotriacetate) hydrate single crystal [C(NH(2))(3)](2)[Zr[N(CH(2)COO)(3)](2)](H(2)O) have been measured in the regions 30-4000 and 80-4000 cm(-1) and correlated with X-ray structural data. The factor group analysis has been applied in the discussion of the dichroic dependence of the vibrational modes. The assignment of the internal vibrations for the [Zr(nitrilotriacetate)2]2- complex ion has been based on the ab initio quantum chemical calculations. The usefulness of the studied crystal as Raman laser converter was analyzed basing on the comparison of the spontaneous and stimulated Raman spectra.  相似文献   

17.
A laser Raman study of oriented single crystals of CdSiF6:6D2O at room temperature as well as at 10 K in all the six polarization geometries has been made. Also a detailed temperature dependent Raman study from room temperature to 10 K in (yy) polarization in the region of internal vibrations and lattice modes has been made. Abrupt changes have been observed in frequency shift, line-width and intensity of some of the bands at about 235 K. Some doubly degenerate modes show splitting at the same temperature. From these observations a phase change at about 235 K is inferred for this salt. It has been suggested that when the system is cooled, the lattice contracts and the water molecules lose their reorientational freedom to some extent which might result in the distortion of the [Cd(OD2)6]2+ octahedra triggering a phase transition.  相似文献   

18.
The rose center in BaF2 is investigated by resonant Raman scattering. The spectra obtained at liquid-helium temperature show multiple order and combination bands of the internal local modes (up to the sixth order), and associated side bands of the lattice. The temperature dependence of the linewidth of the local-mode transitions has been investigated and is explained as being due to anharmonic coupling to the lattice.  相似文献   

19.
To gain insight into the high-pressure polymorphism of RDX, an energetic crystal, Raman spectroscopy results were obtained for hydrostatic (up to 15 GPa) and non-hydrostatic (up to 22 GPa) compressions. Several distinct changes in the spectra were found at 4.0 +/- 0.3 GPa, confirming the alpha-gamma phase transition previously observed in polycrystalline samples. Detailed analyses of pressure-induced changes in the internal and external (lattice) modes revealed several features above 4 GPa: (i) splitting of both the A' and A' ' internal modes, (ii) a significant increase in the pressure dependence of the Raman shift for NO2 modes, and (iii) no apparent change in the number of external modes. It is proposed that the alpha-gamma phase transition leads to a rearrangement between the RDX molecules, which in turn significantly changes the intermolecular interaction experienced by the N-O bonds. Symmetry correlation analyses indicate that the gamma-polymorph may assume one of the three orthorhombic structures: D2h, C2v, or D2. On the basis of the available X-ray data, the D2h factor group is favored over the other structures, and it is proposed that gamma-phase RDX has a space group isomorphous with a point group D2h with eight molecules occupying the C1 symmetry sites, similar to the alpha-phase. It is believed that the factor group splitting can account for the observed increase in the number of modes in the gamma-phase. Spatial mapping of Raman modes in a non-hydrostatically compressed crystal up to 22 GPa revealed a large difference in mode position indicating a pressure gradient across the crystal. No apparent irreversible changes in the Raman spectra were observed under non-hydrostatic compression.  相似文献   

20.
High pressure behavior of alpha-hydroquinone (1,4-dihydroxybenzene) has been studied using Raman spectroscopy up to pressures of 19 GPa. Evolution of Raman spectra suggests two transitions around 3.3 and 12.0 GPa. The first transition appears to be associated with the lowering of crystal symmetry. Above 12.0 GPa, Raman bands in the internal modes region exhibit continuous broadening suggesting that the system is progressively evolving into a disordered state. This disorder is understood as arising due to distortion of the hydrogen-bonded cage across the second transition around 12 GPa.  相似文献   

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