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Reactions of SmI2 in THF with ArSSAr produced two binuclear samarium thiolate complexes [(THF)3I2- Sm(μ-SAr)]2 [Ar=Ph (1), 4-Me2NC6H4 (2)] in high yields. The structure of 2 was characterized by single crystal X-ray crystallography. The crystal of 2 belongs to the triclinic system with space group P 1 and a=0.95705(13) nm, b= 1.22287(14) nm, c= 1.26450(14) nm, a=64.194(11)°, B=78.491(13)°, y=76.176(12)°, V= 1.2860(3) nm^3, Z= 1,μ=4.783 mm^-1, Dc= 1.964 Mg/m^3, M= 1521.19, S= 1.046, R1=0.0358, wR2=0.0910. X-ray analysis revealed that 2 is a thiolate-bridged dimer in which each Sm atom adopts a distorted pentagonal bipyramidal coordi- nation geometry. 相似文献
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Three new organically templated or organically bonded zinc selenates, namely, {H2bipy}Zn(SeO4)2(H2O)21 (bipy=4,4′-bipyridine), {H2pip}{Zn(SeO4)2(H2O)4}·2H2O 2 (pip=piprazine), and Zn(SeO4)(phen)(H2O)23 (phen=1,10-phenanthroline) have been synthesized by hydrothermal reactions. The structure of compound 1 features a 1D chain composed of [Zn(SeO4)2(H2O)2]2− anions. Compound 2 has a 2D layer structure built from {Zn(SeO4)2(H2O)4}2− anions that are cross-linked by doubly protonated piperazine cations via N-H?O hydrogen bonds. The structure of compound 3 contains a 1D chain of Zn(SeO4)(phen)(H2O)2, such chains are further interlinked by hydrogen bonds and π?π interactions to form a 〈200〉 layer. The different roles the templates played have also been discussed. 相似文献
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The octahedral (FeO6)9? and tetrahedral (FeO4)5? clusters in yttrium gallium garnet (YGG): Fe3+ system are investigated based on the 252 × 252 complete energy matrices for d5 configuration ions in trigonal and tetragonal ligand fields, moreover, the EPR and optical spectra are made unified calculation. The results indicate that the defect structures around Fe3+ centres display expansion effects at different temperatures 4.2 and 295 K, and which are close to those in YIG garnet, respectively. Simultaneously, the defect structure parameters for Fe3+ centres in YGG are determined, and the relationship between the defect structure and the temperature has been discussed. 相似文献
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本文综述了有机杂化锑基主族异金属硫属化物的研究进展,对它们的结构和异金属次级结构基元进行了描述、归类和总结;探讨了有机组分分别作为结构导向剂和配体两种角色所起到的不同作用;介绍了这类化合物在离子交换、光催化性能方面的研究;展望了该体系的发展趋势。 相似文献
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本文综述了有机杂化锑基主族异金属硫属化物的研究进展, 对它们的结构和异金属次级结构基元进行了描述、归类和总结;探讨了有机组分分别作为结构导向剂和配体两种角色所起到的不同作用;介绍了这类化合物在离子交换、光催化性能方面的研究;展望了该体系的发展趋势。 相似文献
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在Demons算法的基础上, 将扩散过程看作图像配准, 建立一种新的基于图像配准的Demons 去噪模型. 实验表明, 该模型去噪效果优于经典的Perona-Malik模型, 排除了模型的病态性. 考虑到新模型在图像去噪过程中仅靠梯度信息表示图像的局部特征还不完善, 故将水平集曲率作为控制图像结构的驱动力因素引入到此模型中, 提出了一种新的梯度和曲率双重驱动力的图像去噪模型. 分析和仿真结果表明, 两种新模型都可有效抑制噪声, 清晰度也有明显的提高, 其中双重驱动力的图像去噪模型去噪效果更具优越性. 相似文献
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Mei-Ling Tan Dr. Qing-Hui Guo Dr. Xue-Yuan Wang Tan-Hao Shi Dr. Qian Zhang Sheng-Kai Hou Prof. Dr. Shuo Tong Prof. Dr. Jingsong You Prof. Dr. Mei-Xiang Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(52):23857-23866
Despite the aesthetically appealing structures and tantalizing physical and chemical properties, zigzag hydrocarbon belts and their heteroatom-embedded analogues remain challenging synthetic targets. We report herein the synthesis of diverse O/N-doped zigzag hydrocarbon belts based on selective bridging of the fjords of resorcin[4]arene derivatives through intramolecular SNAr and palladium-catalyzed intermolecular C−N bond formation reactions. Preorganized conformations of mono-macrocyclic, half-belt and quasi-belt compounds were revealed to facilitate cyclization reactions to construct heteroatom-linked octahydrobelt[8]arenes. The acquired products had strained square-prism-shaped belt structures in which all six-membered heterocyclic rings adopted an unusual boat conformation with equatorially configured alkyl groups. The unprecedented heteroatom-bearing belts also exhibited different photophysical and redox properties to those of octahydrobelt[8]arene analogues. 相似文献
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