排序方式: 共有56条查询结果,搜索用时 15 毫秒
21.
Jian-Yong Zhang Yan-Qin Wang Hui-Qi Peng Ai-Ling Cheng En-Qing Gao 《Structural chemistry》2008,19(3):535-539
A new coordination polymer with interesting supramolecular architecture, [Zn(4-tzbz)]
n
(1) (4-tzbz = 4-(tetrazol-5-yl)benzoate), has been synthesized and characterized structurally. In this compound, the zinc(II)
ions are connected by the tetrazole ring in the μ2-1,4 bridging mode and the carboxylate group in the μ2-1,3 syn-anti bridging mode to generate 2D (4,4) sheets, and the adjacent sheets are linked further by the benzene rings to give the 3D
metal–organic framework with a 3,4-connected (83)(84122) topology. This compound in the solid state exhibits photoluminescence assignable to intraligand transitions, and, in particular,
the emission at 400 nm is significantly intensified due to the coordination of the ligand to Zn. 相似文献
22.
23.
Jia QX Tian H Zhang JY Gao EQ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(3):1040-1051
Herein we present a systematic study of the structures and magnetic properties of six coordination compounds with mixed azide and zwitterionic carboxylate ligands, [M(N3)2(2‐mpc)] (2‐mpc=N‐methylpyridinium‐2‐carboxylate; M=Co for 1 and Mn for 2 ), [M(N3)2(4‐mpc)] (4‐mpc=N‐methylpyridinium‐4‐carboxylate; M=Co for 3 and Mn for 4 ), [Co3(N3)6(3‐mpc)2(CH3OH)2] ( 5 ), and [Mn3(N3)6(3‐mpc)2] ( 6 ; 3‐mpc=N‐methylpyridinium‐3‐carboxylate). Compounds 1 – 3 consist of one‐dimensional uniform chains with (μ‐EO‐N3)2(μ‐COO) triple bridges (EO=end‐on); 5 is also a chain compound but with alternating [(μ‐EO‐N3)2(μ‐COO)] triple and [(EO‐N3)2] double bridges; Compound 4 contains two‐dimensional layers with alternating [(μ‐EO‐N3)2(μ‐COO)] triple, [(μ‐EO‐N3)(μ‐COO)] double, and (EE‐N3) single bridges (EE=end‐to‐end); 6 is a layer compound in which chains similar to those in 5 are cross‐linked by a μ3‐1,1,3‐N3 azido group. Magnetically, the three CoII compounds ( 1 , 3 , and 5 ) all exhibit intrachain ferromagnetic interactions but show distinct bulk properties: 1 displays relaxation dynamics at very low temperature, 3 is an antiferromagnet with field‐induced metamagnetism due to weak antiferromagnetic interchain interactions, and 5 behaves as a noninnocent single‐chain magnet influenced by weak antiferromagnetic interchain interactions. The magnetic differences can be related to the interchain interactions through π–π stacking influenced by different substitution positions in the ligands and/or different magnitudes of intrachain coupling. All of the MnII compounds show overall intrachain/intralayer antiferromagnetic interactions. Compound 2 shows the usual one‐dimensional antiferromagnetism, whereas 4 and 6 exhibit different weak ferromagnetism due to spin canting below 13.8 and 4.6 K, respectively. 相似文献
24.
Two complexes with a zwitterionic dicarboxylate ligand,Mn(L)2(H2O)4 1 and Co(L)2(H2O)4 2(L = 1-carboxymethylpyridinium-4-carboxylate),were synthesized and structurally characterized.Complex 1 crystallizes in monoclinic,space group P21 with a = 6.490(2),b = 19.210(7),c = 7.813(3) ,β = 92.716(5)o,V = 972.9(6) 3,Z = 2,Mr = 487.28,Dc = 1.663 g/cm3,F(000) = 502,μ = 0.749 mm-1,S = 1.060,the final R = 0.0377 and wR = 0.0893 for 3292 observed reflections with I 2σ(I).Complex 2 is isomorphous with 1,with a = 6.478(2),b = 19.052(7),c = 7.742(3) ,β = 92.690(4)o,V = 954.6(6) 3,Z = 2,Mr = 491.28,Dc = 1.709 g/cm3,F(000) = 506,μ = 0.971 mm-1,S = 1.035,the final R = 0.0425 and wR = 0.0809 for 3289 observed reflections with I 2σ(I).In the compounds,the mononuclear [M(L)2(H2O)4] units with trans-octahedral coordination geometry are linked into 3D architectures via hydrogen bonding(or second-sphere coordination) involving carboxylate groups and coordinated water molecules.The 3D networks illustrate a 3,8-connected net with Schlfli symbol(4·62)2(42·623·83). 相似文献
25.
Jin-Kui Tang Shu-Feng Si En-Qing Gao Dai-Zheng Liao Zong-Hui Jiang Shi-Ping Yan 《Journal of chemical crystallography》2002,32(9):331-335
A new ionic complex [Ni(meso-cth)][Cr(ox)2(bpy)](H2O)(ClO4) [meso-cth = meso-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, ox = oxalato ainon, bpy = 2,2-bipyridine] was prepared and its structure was determined. The complex was found to crystallized in monoclinic space group P2(1)/n, with a = 13.6000(4) Å, b = 18.763(5) Å, c = 14.995(4) Å, =106.958(5)°, V = 3659.9(17) Å3, and Z = 4. The structure consisted of cationic [Ni(meso-cth)]2+, anionic [Cr(ox)2(bpy)]–, and perchlorate anions; the cationic [Ni(meso-cth)]2+ and anionic [Cr(ox)2(bpy)]– units were related by weak coordination bonds and hydrogen bonds. 相似文献
26.
A novel 3D assembly of molecular cobalt cubes, where the mixed-valence cubes are linked by macrocyclic nickel(II) complexes through coordination and hydrogen bonds, has been constructed by the metalloligand strategy. 相似文献
27.
Two coordination polymers formulated as [{[Co(2)(L)(N(3))(4)]·2DMF}(n) (1) and [Mn(2)(L)(H(2)O)(0.5)(N(3))(8)](n) (2) (L = 1,4-bis(4-carboxylatopyridinium-1-methyl)benzene) were synthesized and structurally and magnetically characterized. In compound 1, the anionic uniform Co(II) chains with mixed (μ-EO-N(3))(2)(μ-COO) triple bridges (EO = end-on) are cross-linked by the cationic bis(pyridinium) spacers to generate 2D coordination layers. It was demonstrated that the triple bridges mediate ferromagnetic coupling and that the compound represents a new example of the rare systems exhibiting the coexistence of antiferromagnetic ordering, metamagnetism, and slow magnetic dynamics. Compound 2 features the magnetic Δ-chain formed from isosceles triangular units with single μ-EE-N(3) and double (μ-EO-N(3))(μ-COO) bridges (EE = end-to-end). The Δ-chains are interlinked by long organic ligands into a 3D framework with novel net topology and 3-fold interpenetration. The magnetic properties of 2 indicate the presence of spin frustration characteristic of Δ-chains with antiferromagnetic interactions. 相似文献
28.
Three transition-metal coordination polymers with azide and/or carboxylate bridges have been synthesized from 4-(3-pyridyl)benzoic acid (4,3-Hpybz) and 4-(4-pyridyl)benzoic acid (4,4-Hpybz) and characterized by X-ray crystallography and magnetic measurements. Compound 1, [Cu(4,3-pybz)(N(3))](n), consists of 2D coordination networks in which the uniform chains with (μ-EO-N(3))(μ-COO) double bridges are cross-linked by the 4,3-pybz ligands. Compound 2, [Cu(2)(4,4-pybz)(3)(N(3))](n)·3nH(2)O, consists of 2-fold interpenetrated 3D coordination networks with the α-Po topology, in which the six-connected dinuclear motifs with mixed (μ-EO-N(3))(μ-COO)(2) (EO = end-on) triple bridges are linked by the 4,4-pybz spacers. Compound 3, [Mn(4,4-pybz)(N(3))(H(2)O)(2)](n), contains 2D manganese(II) coordination networks in which the chains with single μ-EE-N(3) bridges (EE = end-to-end) are interlinked by the 4,4-pybz ligands, and the structure also features a 2D hydrogen-bonded network in which Mn(II) ions are linked by double triatomic bridges, (μ-EE-N(3))(O-H···N) and (O-H···O)(2). Magnetic studies indicated that the mixed azide and carboxylate bridges in 1 and 2 induce ferromagnetic coupling between Cu(II) ions and that 3 features antiferromagnetic coupling through the EE-azide bridge. In addition, compound 1 exhibits antiferromagnetic ordering below 6.2 K and behaves as a field-induced metamagnet. A magnetostructural survey indicates a general trend that the ferromagnetic coupling through the mixed bridges decreases as the Cu-N-Cu angle increases. 相似文献
29.
Three isomorphous metal-organic frameworks of formula [M(ppdc)(H(2)O)(2)](n) [M = Mn(II), Fe(II), and Co(II)] were synthesized from sodium p-phenylenediacrylic (Na(2)ppdc). Crystallographic studies revealed that the compounds are layer-pillared 3D frameworks in which the square-grid M(II) layers with single carboxylate bridges are interlinked by long organic spacers with large interlayer separations of about 13 ?. Magnetic investigations indicated that they all display intralayer antiferromagnetic interactions through the carboxylate bridges in the unusual skew-skew coordination mode but the bulk behaviors are quite different. The Co(II) compound, like most compounds containing similar M-O-C-O-M layers, shows no 3D magnetic ordering down to 2 K, while the Mn(II) and Fe(II) compounds exhibit spin-canted ordering, behaving as a weak ferromagnet (T(C) = 3.8 K) and a metamagnet (T(N) = 3.8 K, H(c) = 650 Oe), respectively. Spin-canted ordering is still a rarity in this series of materials. Magnetostructural comparisons with analogous compounds indicate that the occurrence of spin-canted ordering can be related to the uncommon skew-skew and anti-anti coordination modes of carboxylate bridges, which induce stronger antiferromagnetic interactions than the common syn-anti mode. 相似文献
30.
Xiong-Bing Qian Qi Yue Qin-Xiang Jia Hui-Qi Peng En-Qing Gao 《Journal of chemical crystallography》2011,41(5):751-756