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81.
Hyo-Suk Kim Sheby Mary George Eun Ae Jung Jeong Hwan Han Bo Keun Park Seung Uk Son 《Journal of Coordination Chemistry》2016,69(17):2591-2597
New magnesium complexes, [Et2Mg3(dmamp)4] (1) and [(CH2=CH)2Mg3(dmamp)4] (2), were prepared by the reaction of alkylmagnesium bromide with sodium 1-dimethylamino-2-methyl-2-propoxide [Na(dmamp)] in THF. Complexes 1 and 2 were characterized by 1H and 13C NMR spectroscopies, FTIR spectroscopy, elemental analysis, and single-crystal X-ray diffraction (XRD) analysis. The XRD analysis showed that these complexes are trinuclear where the alkoxy O is the μ2-O bridge between the Mg ions. Among the three metal centers, the two terminal Mg ions are five coordinate and have a square–pyramidal geometry, whereas the central Mg is four coordinate with a distorted tetrahedral geometry. The combination of ethyl and vinyl groups with sterically bulky aminoalkoxide ligands plays an important role in stabilizing the molecule. 相似文献
82.
1 IntroductionAwidevarietyoftrinuclearoxo carboxylatocomplexeshavebeensynthesizedandstudiedfortheirinterestingchemicalandphysicalproperties[1 ].Thevibrationalspectraofmostofthesecompounds,whichgivemuchinformationaboutthestructureandelectrondelocalization… 相似文献
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84.
系统地报道了9个三核钼硫簇合物的合成和结构表征. 晶体结构分析表明, 其中化合物1和6具有[Mo3(μ3-S)(μ-S)3]簇芯, 化合物2和3具有不对称的簇芯[Mo3(μ3-S)(μ-O)(μ-S)2], 化合物4, 5, 7和8具有少见的[Mo3(μ3-O)(μ-S)3]簇芯, 而化合物9则具有[Mo3(μ3-S)(μ-S2)3]簇芯. 这一系列不同的簇芯以及桥配体和“松散”配位的端配体造成了不同的堆积结构. 讨论了前三种簇芯的电子结构, 并根据它们的立体构型和电子结构对某些重要的谱学表征结果做了合理的诠释. 测定了化合物4的变温电导率, 表明其具有半导体导电性能. 相似文献
85.
合成了μ3-氧桥三核锰配合物Mn3O(Salala-β)3·3H2O和四核锰配合物Mn4O2(sa-lala-β)3(ClO4)2·8H2O,其中salala-β2-是水杨叉-β-丙氨酸三齿希夫碱的负二价阴离子,运用元素分析、化合价测定、电导率、磁化率、热重分析、红外和电子光谱等实验结果对其进行了表征,并提出了配合物的可能结构。 相似文献
86.
The two linear hetero‐trinuclear metallic complexes with Cu2+, Ni2+ and Zn2+ ions, [CuNi2 {(CHO2)(SALPD)[(CH3)2NCHO]}2],(I) and [ZnNi2{(CHO2)(SALPD)[(CH3)2NCHO]}2],(II), form crystals which belong to the monoclinic system, space group P21/c, with unit cell dimensions a=10.537(4), b=16.612(5), c=13.837(3) Å, β=111.09(5)°, V=2259.8(12) Å3 in (I) and a=10.525(4), b=16.658(5), c=13.826(3) Å, β=111.11(5) °, V=2261.4(8) Å3 in (II), respectively. The coordinations around the M (Ni2+, Cu2+, Zn2+) ions in the title complexes are distorted octahedrals. The stereochemistries of the bridge ligands, linking to the metal ions each other, are changed between Ni…M (Cu2+, Zn2+) distances. The Ni…M (Cu2+, Zn2+) distances are 3.0469(13) and 3.0645(14), respectively. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
87.
Analysis of the Role of Peripheral Ligands Coordinated to ZnII in Enhancing the Energy Barrier in Luminescent Linear Trinuclear Zn‐Dy‐Zn Single‐Molecule Magnets 下载免费PDF全文
Dr. Jean Pierre Costes Dr. Silvia Titos‐Padilla Itziar Oyarzabal Tulika Gupta Dr. Carine Duhayon Prof. Gopalan Rajaraman Prof. Enrique Colacio 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(44):15785-15796
Three new Dy complexes have been prepared according to a complex‐as‐ligand strategy. Structural determinations indicate that the central Dy ion is surrounded by two LZn units (L2? is the di‐deprotonated form of the N2O2 compartmental N,N′‐2,2‐dimethylpropylenedi(3‐methoxysalicylideneiminato) Schiff base. The Dy ions are nonacoordinate to eight oxygen atoms from the two L ligands and to a water molecule. The Zn ions are pentacoordinate in all cases, linked to the N2O2 atoms from L, and the apical position of the Zn coordination sphere is occupied by a water molecule or bromide or chloride ions. These resulting complexes, formulated (LZnX)‐Dy‐(LZnX), are tricationic with X=H2O and monocationic with X=Br or Cl. They behave as field‐free single‐molecule magnets (SMMs) with effective energy barriers (Ueff) for the reversal of the magnetization of 96.9(6) K with τ0=2.4×10?7 s, 146.8(5) K with τ0=9.2×10?8 s, and 146.1(10) K with τ0=9.9×10?8 s for compounds with Zn?OH2, Zn?Br, and Zn?Cl motifs, respectively. The Cole–Cole plots exhibit semicircular shapes with α parameters in the range of 0.19 to 0.29, which suggests multiple relaxation processes. Under a dc applied magnetic field of 1000 Oe, the quantum tunneling of magnetization (QTM) is partly or fully suppressed and the energy barriers increase to Ueff=128.6(5) K and τ0=1.8×10?8 s for 1 , Ueff=214.7 K and τ0=9.8×10?9 s for 2 , and Ueff=202.4 K and τ0=1.5×10?8 s for 3 . The two pairs of largely negatively charged phenoxido oxygen atoms with short Dy?O bonds are positioned at opposite sides of the Dy3+ ion, which thus creates a strong crystal field that stabilizes the axial MJ=±15/2 doublet as the ground Kramers doublet. Although the compound with the Zn?OH2 motifs possesses the larger negative charges on the phenolate oxygen atoms, as confirmed by using DFT calculations, it exhibits the larger distortions of the DyO9 coordination polyhedron from ideal geometries and a smaller Ueff value. Ab initio calculations support the easy‐axis anisotropy of the ground Kramers doublet and predict zero‐field SMM behavior through Orbach and TA‐QTM relaxations via the first excited Kramers doublet, which leads to large energy barriers. In accordance with the experimental results, ab initio calculations have also shown that, compared with water, the peripheral halide ligands coordinated to the Zn2+ ions increase the barrier height when the distortions of the DyO9 have a negative effect. All the complexes exhibit metal‐centered luminescence after excitation into the UV π–π* absorption band of ligand L2? at λ=335 nm, which results in the appearance of the characteristic DyIII (4F9/2→6HJ/2; J=15/2, 13/2) emission bands in the visible region. 相似文献
88.
The coordination polymer, [Mn3(bpta)2(bip)2], (H3bpta = biphenyl-3,3',5-tricar- boxylic acid, bip = 2,6-bis(imidazole-1-yl)pyridine), has been synthesized under hydrothermal con- ditions and characterized by elemental analysis, FT-IR, XRD, TGA and single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 14.919(3), b = 9.780(2), c = 20.352(7) A, V = 2344.4(10) A3, Z= 2, C52H32Mn3N10012, Mr = 1153.70, Dc = 1.634 g/cm3, p(MoKa) = 0.876 mm-1, F(000) = 1170, the finalR = 0.0605 and wR = 0.1177. The complex forms a 2D layer with trinuclear Mn(II) units and further assembles into a 3D supramolecular network structure through C-H..'O hydrogen bonding and C-H...π interactions. Moreover, the negative J value indicates the presence of antiferromagnetic coupling between the Mn(II) ions within a trinuclear unit. 相似文献
89.
90.
Masoud Mirzaei Hossein Eshtiagh‐Hosseini Zahra Karrabi Behrouz Notash 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(10):1140-1143
4‐Hydroxypyridine‐2,6‐dicarboxylic acid (chelidamic acid, hypydc[H]H2) reacts with MnCl2·2H2O in the presence of piperazine in water to afford the title complex, {[Mn3(C7H2NO5)2(H2O)8]·3H2O}n or {[Mn3(hypydc)2(H2O)8]·3H2O}n. This compound is a one‐dimensional coordination polymer, with the twofold symmetric repeat unit containing three metal centres. Two different coordination geometries are observed for the two independent MnII metal centres, viz. a distorted pentagonal bipyramid and a distorted octahedron. The 4‐oxidopyridine‐2,6‐dicarboxylate anions and two of the water molecules act as bridging ligands. The zigzag‐like geometry of the coordination polymer is stabilized by hydrogen bonds. O—H...O and C—H...O hydrogen bonds and water clusters consolidate the three‐dimensional network structure. 相似文献