排序方式: 共有100条查询结果,搜索用时 15 毫秒
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在不同反应条件下,采用三唑衍生物作为配体与乙酸锰和硝酸锌反应,合成了2个具有三维结构的配位化合物{Mn(pytyba)(H2O)3]·2H2O}n(1)和{[Zn(pytyba)(H2O)3]·4H2O}n(2),并通过元素分析、热重分析、荧光性、X射线单晶衍射对化合物进行分析。结构分析表明1和2有许多共同特征:两个聚合物的晶体均属于单斜晶系,C2/c空间群,Mn2+和Zn2+均为六配位畸变八面体配位结构,具有相似的热稳定性、荧光性以及相近的孔隙率。配体中的氧原子与金属离子配位形成一维链状结构,然后又通过O-H…N、O-H…O氢键作用和π…π芳香堆积形成超分子结构。此外,通过测定化合物抗氧化活性(SOD)的经典方法-Marklund法对配合物1和2的抗氧化活性进行了研究。 相似文献
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Ren C Hou L Liu B Yang GP Wang YY Shi QZ 《Dalton transactions (Cambridge, England : 2003)》2011,40(4):793-804
Six new coordination polymers, namely {[Zn(btec)(0.5)(btmb)]·2H(2)O}(n) (1), {[Co(btec)(0.5)(btmb)(H(2)O)]·3H(2)O}(n) (2), {[Cu(btec)(0.5)(btmb)]·H(2)O}(n) (3), {[Cu(4)(btc)(4)(btmb)(4)]·H(2)O}(n) (4), {[Co(3)(bta)(2)(btmb)(2)]·2H(2)O}(n) (5), [Co(Hbta)(btmb)](n) (6) (H(4)btec = 1,2,4,5-benzenetetracarboxylate, H(3)btc = 1,3,5-benzenetricarboxylate, H(3)bta = 1,2,4-benzenetricarboxylate and btmb = 4,4'-bis(1,2,4-triazol-1-ylmethyl)biphenyl), have been successfully synthesized under hydrothermal conditions. All these complexes were structurally determined by single-crystal X-ray diffraction, elemental analysis, IR, TGA and XRD. Crystal structural analysis reveals that 1 is the first example of an unusual 3D framework with (8(6)) topology containing a 2D molecular fabric structure. Complex 2 exhibits a 3D NbO network with (6(4)·8(2)) topology. In 3, Cu(II) ions are coordinated by anti-conformational btmb ligands to form left- and right-handed double helices, which are further bridged by the 4-connected btec(4-) anions to give a 3D porous network. Complex 4 presents a rare 3D gra network structure with (6(3))(6(9)·8) topology. 5 and 6 were obtained through controllable pH values of solution, 5 features a scarce binodal (3,8)-connected tfz-d framework with the trinuclear Co(II) clusters acting as nodes, whereas 6 has an extended 2D 4(4) grid-like layer and the adjacent 2D layers are interconnected by strong hydrogen bonding interactions into a 3D supramolecular framework. The structural diversities indicate that distinct organic acid ligands, the nature of metal ions and the pH value play crucial roles in modulating the formation of the resulting coordination complexes and the connectivity of the ultimate topological nets. Moreover, magnetic susceptibility measurement of 5 indicates the presence of weak ferromagnetic interactions between the Co(II) ions bridged by carboxylate groups. 相似文献
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研究事件空间中单面非Chetaev型非完整系统Nielsen方程的Mei对称性和Mei守恒量.建立系统的运动微分方程,给出系统Mei对称性、弱Mei对称性、强Mei对称性的定义和判据,得到由Mei对称性直接导致的Mei守恒量的存在条件以及Mei守恒量的表达式.举例说明结果的应用.
关键词:
事件空间
Nielsen方程
单面非Chetaev型非完整系统
Mei守恒量 相似文献
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Ya-Wen Zhang Dr. Rajorshi Das Yang Li Prof. Dr. Yao-Yu Wang Prof. Dr. Ying-Feng Han 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(21):5472-5479
The metal-controlled self-assembly of organometallic molecular cylinders from a series of imidazo[1,5-a]pyridine-based tris-NHC ligands is described in this report. The imidazo[1,5-a]pyridinium salts H3- L (PF6)3 ( L = 4 a – 4 c ) were treated with 1.5 equivalents of Ag2O to yield the trinuclear AgI hexacarbene cages [Ag3( L )2](PF6)3 ( L = 4 a – 4 c ), in which three AgI are sandwiched between the two tricarbene ligands. The silver(I) complexes [Ag3( L )2](PF6)3 underwent a facile transmetalation reaction in the presence of 3 equivalents of [AuCl(tht)] (tht=tetrahydrothiophene) to furnish the trinuclear AuI cylinder-like cages [Au3( L )2](PF6)3 ( L = 4 a – 4 c ) without destruction of the metallosupramolecular structure. The new hexacarbene assemblies feature a large cavity that can easily accommodate a molecule of dimethyl sulfoxide as molecular guest. This is the first study of a unique “host–guest” system containing an organometallic cylinder-like cage derived exclusively from poly-NHC ligands. 相似文献
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Lin Cui Qin-Hui Wang Jin-Wei Duan Kang Wang Yao-Yu Wang 《Journal of Coordination Chemistry》2018,71(3):421-427
A 2-D chiral entangled coordination polymer, {Mn3(2,2′-bpy)2(3-cpta)2·H2O}n (1) (3-H3cpta=3-(3′-carboxyphenoxy)phthalic acid, 2,2′-bpy=2,2′-bipyridine), has been synthesized via the solvothermal method. X-ray diffraction analysis reveals that 1 consists of one right-handed helical chain and one wavelike 2-D plane, which are connected with each other through hydrogen bonds and π···π interactions to generate a 3-D supra-molecule. Thermal gravimetric analysis shows that 1 possesses good thermal stability. Temperature dependent magnetic susceptibilities have also been measured from 1.8 to 300 K, which shows 1 to be anti-ferromagnetic. 相似文献
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Qianqian Chu Dr. Shihui Zhang Dr. Xiuyuan Li Panyue Guo Prof. Aiyun Fu Dr. Bo Liu Prof. Yao-Yu Wang 《化学:亚洲杂志》2021,16(10):1233-1236
The separation of C2H2 from C2H4 is one of the most challenging tasks due to the similarity of their physical properties. In addition, green synthetic protocol and adsorbent's stability are also the major concerns during the separation. Herein, under hydrothermal green synthesis conditions, an ultrastable ultramicroporous Zn-MOF was designed and synthesized with a high yield. The pore diameter of the Zn-MOF is 3.6 Å, which lies in between the diameters of C2H2 (3.3 Å) and C2H4 (4.2 Å) molecules, leading to an efficient separation of the C2H2/C2H4 mixtures by the sieving effect. The practical separation performance of C2H2/C2H4 was confirmed by the dynamic breakthrough experiments. Moreover, the high stability enables the adsorption capacity of the Zn-MOF to C2H2, which can be maintained under a wide range of pH (1–13). Molecular simulations were also performed to identify the different C2H2- and C2H4-binding sites in Zn-MOF. 相似文献
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Structural equation and Mei conserved quantity of Mei symmetry for Appell equations in holonomic systems with unilateral constraints are investigated. Appell equations and differential equations of motion for holonomic mechanic systems with unilateral constraints are established. The definition and the criterion of Mei symmetry for Appell equations in holonomic systems with unilateral constraints under the infinitesimal transformations of groups are also given. The expressions of the structural equation and Mei conserved quantity of Mei symmetry for Appell equations in holonomic systems with unilateral constraints expressed by Appell functions are obtained. An example is given to illustrate the application of the results. 相似文献
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Xing-Xing Gou Tong Liu Prof. Dr. Yao-Yu Wang Prof. Dr. Ying-Feng Han 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(38):16826-16832
Controlling the size and surface functionalization of nanoparticles (NPs) can lead to improved properties and applicability. Herein, we demonstrate the efficiency of the metal-carbene template approach (MCTA) to synthesize highly robust and soluble three-dimensional polyimidazolium cages (PICs) of different sizes, each bearing numerous imidazolium groups, and use these as templates to synthesize and stabilize catalytically active, cavity-hosted, dispersed poly-N-heterocyclic carbene (NHC)-anchored gold NPs. Owing to the stabilization of the NHC ligands and the effective confinement of the cage cavities, the as-prepared poly-NHC-shell-encapsulated AuNPs displayed promising stability towards heat, pH, and chemical regents. Most notably, all the Au@PCCs (PCC=polycarbene cage) exhibited excellent catalytic activities in various chemical reactions, together with high stability and durability. 相似文献