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121.
Linda Fluyt Kris Driesen Christiane Görller-Walrand 《Journal of solid state chemistry》2005,178(2):429-434
A new approach to unravel the site symmetry of lanthanides in solutions is presented. The magnetic circular dichroism spectra of Eu3+ in the symmetries D3h, C4v and D2d are simulated. In these simulations, the main idea is to introduce the magnetic field along a 3-fold axis, being the resultant of the three equivalent X-, Y- and Z-direction of a cube. This implies that the parallel and perpendicular Zeeman effects are taken into account simultaneously. 相似文献
122.
Makoto Wakeshima Nobuyuki Taira Aya Tobo Yasuo Yamaguchi 《Journal of solid state chemistry》2003,174(1):159-164
Magnetic and electrical properties are investigated for quaternary neodymium sulfides BaNd2TS5 (T=Co, Zn) through the specific heat, neutron diffraction, and electrical conductivity measurements. Their electrical conductivities show semiconductive behavior, which follows the Arrhenius temperature dependence with the activation energy of Ea=1.46 eV for BaNd2ZnS5 and Ea=1.19 eV for BaNd2CoS5. The specific heat of BaNd2ZnS5 has a λ-type anomaly at 2.8 K due to the antiferromagnetic ordering of the Nd3+ moments and a Schottky-type anomaly at around 60 K, which results from the crystal field splitting of the 4I9/2 ground state of the Nd3+ ion. The specific heat of BaNd2CoS5 shows two λ-type anomalies at 5.7 K due to the antiferromagnetic ordering of Nd3+ and at 58 K due to the antiferromagnetic ordering of Co2+. The latter overlaps with the Schottky-type anomaly due to the crystal field splitting of the Nd3+ ion. Neutron diffraction measurements for BaNd2CoS5 show that a magnetic arrangement of the Co2+ moments has a collinear antiferromagnetic structure, while that of the Nd3+ moments has a noncollinear one. 相似文献
123.
Robert S. Walters 《Tetrahedron letters》2005,46(38):6487-6489
2′,3′,4′,5′,6′,7′-Hexahydrodispiro[cyclopropane-1,1′-anthracene-8′,1″-cyclopropane] (1) was prepared by double olefination (Wittig) and double methylenation (Furukawa) of 1,8-dioxo-1,2,3,4,5,6,7,8-octahydroanthracene (4) that was in turn prepared in two steps from 1,3-dibromobenzene. The X-ray structure of 1 shows that the C-9-H of its anthracene core is located 2.6 Å from the centroids of each of the flanking cyclopropane rings. The 1H NMR spectrum of 1 shows that the C-9-H resonance (δ 5.95) falls 0.84 ppm upfield from the C-10-H resonance (δ 6.79). 相似文献
124.
在INDO/CI方法基础上, 用自己编制的计算二阶非线性极化系数β_(ijk)程序, 计算了苯胺、硝基苯、对硝基苯胺和4-硝基-4′-胺基二苯乙烯的β_(ijk), 并研究了其对外部激光场频率的依赖关系。结果表明, 分子内的电荷转移是产生非线性光学现象的根本原因, 而作为外因的激光场对二阶非线性光学系数的大小和方向也有直接的重要作用。当激光场频率与分子的共振频率接近时, 二阶非线性极化系数变得非常大, 在共振频率附近, β_(ijk)改变符号且Kleinman对称性被打破。 相似文献
125.
Ana B. Gaspar 《Coordination chemistry reviews》2005,249(23):2661-2676
One of the most important trends in the spin crossover (SCO) field is focused on the synthesis of new molecule-based functional materials in which the SCO properties may be combined with other physical or chemical properties in a synergic fashion. The current stage of investigations regarding interplay and synergic effects between SCO, magnetic coupling, liquid crystalline properties, host-guest interactions, non-linear optical properties, electrical conductivity, and ligand isomerization is highlighted and discussed. 相似文献
126.
Yu. B. Vysotsky V. S. Bryantsev O. A. Gorban 《Chemistry of Heterocyclic Compounds》2002,38(12):1451-1468
The effects of benzannellation, phenyl substitution at the nitrogen atom, protonation at the carbene carbon, ionization, and the state of the carbene center (2 or 2) on the electronic structure, diamagnetic susceptibility, induced -electron ring currents, the 1H, 13C, and 14N chemical shifts, and the energies of the lowest electronic transitions of imidazol-2-ylidenes and their oxo and thio analogs were examined in the bound version of -electron perturbation theory. The calculated and experimental data are compared. 相似文献
127.
Xiao‐Yan Chen Peng Cheng Shi‐Ping Yan Dai‐Zheng Liao Zong‐Hui Jiang 《无机化学与普通化学杂志》2005,631(15):3104-3107
A novel two‐dimensional cobalt complex, [Co(btrm)2(dca)]ClO4 ( 1 , btrm = 1,2‐bis(1,2,4‐triazole‐1‐yl)methane, dca = dicyanamide), was synthesized and characterized. X‐ray diffraction analyses reveal that the title complex crystallizes in the monoclinic space group C2/m with a = 29.507(13)Å, b = 17.804(8) Å, c = 14.709(7) Å, β = 119.916(7)°, Z = 12, and R1 = 0.0784, wR2 = 0.2041. The cobalt atom involves a six‐coordinated CoN6 environment, with a distorted octahedral coordination. Two btrm ligands connect the CoII atoms with the exodentate nitrogen atoms on the 4‐position of triazole rings to form a sixteen‐membered rhombic grid. The unprecedented double btrm bridges and μ1,5‐dca bridge connect the cobalt atoms to form a two‐dimensional grid‐like layered structure. The spectroscopic and magnetic properties have also been investigated. 相似文献
128.
Karl Krmer Hans U. Güdel Gerd Meyer Thorsten Heuer Norman N. Edelstein Bernd Jung Lukas Keller Peter Fischer Eugeniusz Zych Janusz Drozdzynski 《无机化学与普通化学杂志》1994,620(8):1339-1345
The ternary uranium(III) halides A2UX5 (A = K, Rb; X = Cl, Br, I) have been prepared from the binary components AX and UX3 in sealed tantalum containers. According to their Guinier X-ray powder patterns, they all crystallize with the K2PrCl5/Y2HfS5 type of structure. Lattice constants for ambient temperature are reported. Single-crystal structure refinemens were undertaken for K2UI5 and Rb2UCl5. Magnetic susceptibility data were recorded with a SQUID magnetometer from liquid helium to room temperature. One-dimensional (intrachain) and three-dimensional antiferromagnetic ordering occur at low temperatures dependent upon the U3+? U3+ distance. Absorption spectra were recorded between 4 000 and 28 000 cm?1. They show f—f transitions typical for U3+ and, depending on the halide, very strong f—d transitions above 14 000 to 15 000 cm?1, respectively. 相似文献
129.
Rudolf Sobczak 《Monatshefte für Chemie / Chemical Monthly》1979,110(3):721-727
Magnetic measurements onHeusler alloys (Co,T)2
XY (field and temperature dependence) are performed around theCurie points (temperature range:T
C–50 toT
C+50). A method otherwise used to get rid of ferromagnetic impurities only (
g
versus 1/H plot) is applied to pure ferromagnets and yields completely new
g
(extrap.) versusT curves with a maximumT
max>
T
C. The method was applied to pure gadolinium first which has aCurie point within the accessible region of the susceptibility measuring device. 相似文献
130.
Ichimin Shirotani Yousuke Shimaya Chihiro Sekine 《Journal of solid state chemistry》2003,174(1):32-34
New filled skutterudites with heavy lanthanide, LnFe4P12 (Ln=Tb, Dy, Ho, Er, Tm, Yb, Lu and Y) have systematically been prepared for the first time by the high-pressure technique. The relationship between lattice constants and atomic numbers of lanthanide (including Y) is established for LnFe4P12. Electrical and magnetic properties of several new filled skutterudites with heavy lanthanide have been studied at low temperatures; YFe4P12 shows a superconducting transition at around 7 K, and DyFe4P12 behaves as a ferromagnet below 10 K. Electrical and magnetic anomalies in DyFe4P12 and YFe4P12 are mainly discussed. 相似文献