共查询到20条相似文献,搜索用时 15 毫秒
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Bo Liu Shuang Wei Yan Xing Dr. Dan Liu Dr. Zhan Shi Prof. Xianchun Liu Xiujuan Sun Suying Hou Zhongmin Su Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(22):6625-6631
The preparation of exquisite hierarchical worm‐like Co1?xS (x=0.75) microtubes by a one‐pot complex–surfactant‐assisted hydrothermal method is successfully achieved for the first time. The hierarchical structures of the microtube wall are assembled from numerous interleaving hexagonal nanoplates. X‐ray diffraction, X‐ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and high‐resolution transmission electron microscopy were used to characterize the samples. The experimental results indicate that the “soft template” surfactant cetyltrimethylammonium bromide and the chelating ethylenediamine both play important roles for the formation of hierarchical Co1?xS microtubes. A possible formation mechanism for the growth processes is proposed. Additionally, the electrochemical and magnetic properties of Co1?xS microtubes were systematically studied. 相似文献
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Trinuclear [CoIII2–LnIII] (Ln=Tb,Dy) Single‐Ion Magnets with Mixed 6‐Chloro‐2‐Hydroxypyridine and Schiff Base Ligands 下载免费PDF全文
Prof. Dr. Cai‐Ming Liu Prof. Dr. De‐Qing Zhang Prof. Dr. Xiang Hao Prof. Dao‐Ben Zhu 《化学:亚洲杂志》2014,9(7):1847-1853
The Schiff base ligand N1,N3‐bis(3‐methoxysalicylidene)diethylenetriamine (H2valdien) and the co‐ligand 6‐chloro‐2‐hydroxypyridine (Hchp) were used to construct two 3d–4f heterometallic single‐ion magnets [Co2Dy(valdien)2(OCH3)2(chp)2] ? ClO4 ? 5 H2O ( 1 ) and [Co2Tb(valdien)2(OCH3)2(chp)2] ? ClO4 ? 2 H2O ? CH3OH ( 2 ). The two trinuclear [CoIII2LnIII] complexes behave as a mononuclear LnIII magnetic system because of the presence of two diamagnetic cobalt(III) ions. Complex 1 has a molecular symmetry center, and it crystallizes in the C2/c space group, whereas complex 2 shows a lower molecular symmetry and crystallizes in the P21/c space group. Magnetic investigations indicated that both complexes are field‐induced single‐ion magnets, and the CoIII2–DyIII complex possesses a larger energy barrier [74.1(4.2) K] than the CoIII2–TbIII complex [32.3(2.6) K]. 相似文献
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Da‐Yu Wu Dr. Osamu Sato Prof. Yasuaki Einaga Prof. Chun‐Ying Duan Dr. 《Angewandte Chemie (International ed. in English)》2009,48(8):1475-1478
How low can you go? An FeII4 square was prepared by self‐assembly and exhibits both thermally induced and photoinduced spin crossover from a system with four high‐spin (HS) centers to one with two high‐spin and two low‐spin (LS) centers. The spin‐crossover sites are located on the same side of the square, and the spin transition and magnetic interactions (see picture) are synergistically coupled.
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Dr. Viktor Hlukhyy Haiyan He Laura‐Alice Jantke Prof. Dr. Thomas F. Fässler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(38):12000-12007
A new type of Zintl phase is presented that contains endohedrally filled clusters and that allows for the formation of intermetalloid clusters in solution by a one‐step synthesis. The intermetallic compound K5?xCo1?xSn9 was obtained by the reaction of a preformed Co? Sn alloy with potassium and tin at high temperatures. The diamagnetic saltlike ternary phase contains discrete [Co@Sn9]5? clusters that are separated by K+ ions. The intermetallic compound K5?xCo1?xSn9 readily and incongruently dissolves in ethylenediamine and in the presence of 4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo[8.8.8]hexacosane (2.2.2‐crypt), thereby leading to the formation of crystalline [K([2.2.2]crypt)]5[Co2Sn17]. The novel polyanion [Co2Sn17]5? contains two Co‐filled Sn9 clusters that share one vertex. Both compounds were characterized by single‐crystal X‐ray structure analysis. The diamagnetism of K5?xCo1?xSn9 and the paramagnetism of [K([2.2.2]crypt)]5[Co2Sn17] have been confirmed by superconducting quantum interference device (SQUID) and EPR measurements, respectively. Quantum chemical calculations reveal an endohedral Co1? atom in an [Sn9]4? nido cluster for [Co@Sn9]5? and confirm the stability of the paramagnetic [Co2Sn17]5? unit. 相似文献
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Tiantian Yao Jing Lu Dacheng Li Jianmin Dou 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(4):364-367
A new tetranuclear mixed‐valence cobalt complex, namely di‐μ2‐azido‐diazidodiethanolbis{μ2‐2‐[(hydroxyimino)methyl]‐6‐methoxyphenolato}bis{μ3‐6‐methoxy‐2‐[(oxidoimino)methyl]phenolato}dicobalt(II)dicobalt(III) ethanol disolvate, [CoII2CoIII2(C8H7NO3)2(C8H8NO3)2(N3)4(C2H5OH)2]·2C2H5OH, has been synthesized by the reaction of Co(OAc)2·4H2O (OAc is acetate) with 3‐methoxysalicylaldoxime (H2mosao) in an ethanol solution. In the complex, the four Co cations all display distorted octahedral coordination environments and they are bridged by two κ2,κ1,κ1;μ3‐mosao2− ligands, two κ2,κ2;μ2‐Hmosao− ligands and two μ2‐N3− anions to form a tetranuclear [Co4N4O4] cluster. Adjacent clusters are connected through weak C—H...N and C—H...O interactions, resulting in a two‐dimensional supramolecular network parallel to the ac plane. The magnetic properties of the complex have also been studied. 相似文献
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Jian‐Qiang Wang Dr. Saskia Stegmaier Thomas F. Fässler Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(11):1998-2002
Inorganic pentaprismane : The unusual structure of the anion [Co@Ge10]3?, which was obtained by the reaction of K4Ge9 with [Co(C8H12)(C8H13)] in ethylenediamine, raises questions about chemical bonding in the anion. The Zintl ion cluster has virtual D5h symmetry and is a unique example of a ligand‐free cluster that is not a deltahedron. The delocalized chemical bonding is represented in the picture by one of the bonding orbitals of the anion.
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Zhou YL Zeng MH Liu XC Liang H Kurmoo M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(50):14084-14093
We present the synthesis, characterization of the structures, and magnetic properties of five isostructural dodecanuclear coordination clusters of Ni(II) and Co(II): [Co(12)(bm)(12)(NO(3))(O(2)CMe)(6)(EtOH)(6)](NO(3))(5) (1), [Ni(12)(bm)(12)(NO(3))(O(2)CMe)(6)(H(2)O)(3)(EtOH)(3)](NO(3))(5)·2H(2)O (2), mixed-metal composition (Ni/Co 1:1) [Co(6)Ni(6)(bm)(12)(NO(3))(O(2)CMe)(6)(NO(3))(5) (3), and [M(12)(bm)(12)(NO(3))(O(2)CMe)(6)(EtOH)(6)](ClO(4))(5) (M=Co (4), Ni (5)), in which Hbm=(1H-benzimidazol-2-yl)methanol. They consist of analogous structural cores that are constructed by three cubanes (M(4)O(4)) that surround the templating nitrate and bridging auxiliary acetate and the directing ligands bm. They have different magnetic behaviors. Whereas there is the absence of the out-of-phase ac susceptibility (χ') for the Ni(II)-based compounds 2 and 5, the Co(II)-containing compounds 1, 3, and 4 have prominent χ' signals that exhibit frequency dependence, which indicates slow magnetic relaxation behavior above 1.8 K. In particular, the larger perchlorate counterions in 4 further change the overall correlation interaction between clusters, thus leading to an enhanced blocking temperature for the less-symmetrical 4 (pseudo-C(3)) relative to 1 and 3 (true C(3)). Interestingly, electrospray ionization mass spectrometry (ESI-MS) indicates that the three dodecanuclear clusters of 1-3 retain their compositions in solution. The mixed-metal cluster cores of 3 are formed based on the nature of the interchangeability between metal centers in solution. 相似文献
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Dimitrios A. Pantazis Dr. Maylis Orio Dr. Taras Petrenko Dr. Samir Zein Dr. Eckhard Bill Dr. Wolfgang Lubitz Dr. Johannes Messinger Prof. Frank Neese Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(20):5108-5123
Broken‐symmetry DFT calculations on transition‐metal clusters with more than two centers allow the hyperfine coupling constants to be extracted. Application of the proposed theoretical scheme to a tetranuclear manganese complex that models the S2 state of the oxygen‐evolving complex of photosystem II yields hyperfine parameters that can be directly compared with experimental data. The picture shows the metal–oxo core of the model and the following parameters; exchange coupling constant Jij, the expectation value of the site‐spin operator , and the isotropic hyperfine coupling parameters.
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Tandem Silver Cluster Isomerism and Mixed Linkers to Modulate the Photoluminescence of Cluster‐Assembled Materials 下载免费PDF全文
Ren‐Wu Huang Xi‐Yan Dong Bing‐Jie Yan Xiang‐Sha Du Dong‐Hui Wei Prof. Shuang‐Quan Zang Prof. Thomas C. W. Mak 《Angewandte Chemie (International ed. in English)》2018,57(28):8560-8566
Silver chalcogenolate cluster assembled materials (SCAMs) are a category of promising light‐emitting materials the luminescence of which can be modulated by variation of their building blocks (cluster nodes and organic linkers). The transformation of a singly emissive [Ag12(SBut)8(CF3COO)4(bpy)4]n (Ag12bpy, bpy=4,4′‐bipyridine) into a dual‐emissive [(Ag12(SBut)6(CF3COO)6(bpy)3)]n (Ag12bpy‐2) via cluster‐node isomerization, the critical importance of which was highlighted in dictating the photoluminescence properties of SCAMs. Moreover, the newly obtained Ag12bpy‐2 served to construct visual thermochromic Ag12bpy‐2/NH2 by a mixed‐linker synthesis, together with dichromatic core–shell Ag12bpy‐2@Ag12bpy‐NH2‐2 via solvent‐assisted linker exchange. This work provides insight into the significance of metal arrangement on physical properties of nanoclusters. 相似文献
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A Cobalt Pyrenylnitronylnitroxide Single‐Chain Magnet with High Coercivity and Record Blocking Temperature 下载免费PDF全文
Dr. Maria G. F. Vaz Dr. Rafael A. Allão Cassaro Dr. Handan Akpinar Dr. John A. Schlueter Prof. Paul M. Lahti Prof. Miguel A. Novak 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(18):5460-5467
Coordination of a [Co(hfac)2] moiety (hfac=hexafluoroacetylacetonate) with a nitronylnitroxide radical linked to bulky, rigid pyrene (PyrNN) gives a helical 1:1 chain complex, in which both oxygen atoms of the radical NO. groups are bonded to CoII ions with strong antiferromagnetic exchange. The complex shows single‐chain magnet (SCM) behavior with frequency‐dependent magnetic susceptibility, field‐cooled and zero‐field‐cooled susceptibility divergence with a high blocking temperature of around 14 K (a record among SCMs), and hysteresis with a very large coercivity of 32 kOe at 8 K. The magnetic behavior is partly related to good chain isolation induced by the large pyrene units. Two magnetic relaxation processes have been observed, a slower one attributable to longer, and a faster one attributable to short chains. No evidence of magnetic ordering has been found. 相似文献
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A Rare Tetranuclear Thorium(IV) μ4‐Oxo Cluster and Dinuclear Thorium(IV) Complex Assembled by Carbon–Oxygen Bond Activation of 1,2‐Dimethoxyethane (DME) 下载免费PDF全文
Dr. Nicholas E. Travia Dr. Brian L. Scott Dr. Jaqueline L. Kiplinger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(51):16846-16852
The synthesis and X‐ray crystal structure of two new multinuclear thorium complexes are reported. The tetranuclear μ4‐oxo cluster complex Th4(μ4‐O)(μ‐Cl)2I6[κ2(O,O’)‐μ‐O(CH2)2OCH3]6 and the dinuclear complex Th2I5[κ2(O,O’)‐μ‐O(CH2)2OCH3]3(DME) (DME=dimethoxyethane) are formed by C?O bond activation of 1,2‐dimethoxyethane (DME) mediated by thorium iodide complexes. 相似文献