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251.
252.
(PPh4)2[Cl2Re(N3S2)(μ‐NSN)(μ‐N≡ReCl3)]2 – a Rhenium(VII) Complex with a Nitrido, a Dinitridosulfato(II), and a Rhena‐3,5‐dithia‐2,4,6‐triazino Function The title compound has been prepared from PPh4[ReVIICl4(NSCl)2] with N(SiMe3)3 in dichloromethane solution to give red‐brown single crystals, which were suitable for a crystal structure determination. As a by‐product PPh4[ReNCl4] is formed. (PPh4)2[Cl2ReVII(N3S2)(μ‐NSN)(μ‐N≡ReVIICl3)]2 ( 1 ): Space group P21/c, Z = 2, lattice dimensions at –80 °C: a = 1280.8(2), b = 1017.5(1), c = 2467.8(3) pm, β = 95.04(1)°, R = 0.049. The complex anion of 1 consists of a planar ReN3S2‐heterocycle which is connected with the second rhenium atom by a μ‐nitrido bridge as well as by a μ‐dinitridosulfato(II) ligand to form a planar Re2(N)(NSN) six‐membered heterocycle. This [Cl2Re(N3S2)(μ‐NSN)(μ‐N≡ReCl3)]– unit dimerizes via one of the N‐atoms of the (NSN)4– ligand to give a centrosymmetric Re2N2 four‐membered ring. 相似文献
253.
Alkali Metal Nitrido Tecto Metallates(VI) with Networks of Six‐membered Rings of Corner‐sharing Tetrahedra [(MNN3/2)6] with M = Mo, W of the Unexpected Composition A9+x[M6N15] with A = Rb, Cs and 0 < x < 1 Reactions of metal powders of Mo and W respectively with amides and azides of Rb and Cs lead to the compounds Rb9+x[W6N15] and Cs9+x[M6N15] with M = Mo, W and 0 < x < 1. The reactions are carried out at 650 °C in autoclaves for salt melts and are finished within 5 d. Crystals of the compounds are embedded in a matrix of the corresponding alkali metal. These metals result from the thermal decomposition of the amides and azides used in high molar ratios. The metals are washed out by liquid ammonia. Besides microcrystalline material of the above mentioned compounds single crystals suitable in size for x‐ray structure determinations were isolated. The compounds crystallize in the space group R3c (No. 167) with Z = 6 and the following lattice constants: Rb9+x[W6N15]: a = 12.743(7) Å, c = 27.794(8) Å, c/a = 2.181 Cs9+x[Mo6N15]: a = 13.104(5) Å, c = 28.430(9) Å, c/a = 2.170 Cs9+x[W6N15]: a = 13.136(5) Å, c = 28.472(6) Å, c/a = 2.167 The metal centres of tetrahedra [MNN3/2] are condensated to cyclohexane analogue six‐membered rings in chair‐form via nitrogen atoms and axial ones connect them to a three‐dimensional network. Nine – as to the formula unit – of the alkali metal atoms are located in vacancies of the anionic partial structure. The residual atoms with 0 < x < 1 centre the six‐membered rings and are coordinated planar hexagonal by N neighbours. 相似文献
254.
Synthesis and Structure of [(Me2PhP)3Cl2ReN]2ReCl4, [(Me2PhP)3Cl2ReN]2ReCl4 · 2 SbCl3 and [Re(NH)Cl2(PMe2Ph)3][SbCl6] The reaction of ReNCl2(PMePh)3 with SbCl5 in toluene yields the trinuclear complex [(Me2PhP)3Cl2Re≡N]2ReCl4 · 2 SbCl3 ( 1 · 2 SbCl3). It forms triclinic crystals with the composition 1 · 2 SbCl3, as well as monoclinic crystals 1 · 2 SbCl3 · 4 C7H8. The monoclinic crystals with the space group P21/c, and a = 1212.3(2), b = 2098.5(4), c = 1827.7(3) pm, β = 95.51(1)°, Z = 2, have been used for a crystal structure determination. In the centrosymmetric complex 1 two complexes ReNCl2(PMe2Ph)3 coordinate with their nitrido ligands a square planar, central unit ReCl4. The SbCl3 molecules are coordinated by chlorine bridges to Cl atoms of 1 , and, in addition, connect the complexes 1 with each other. The SbCl3 free compound 1 is obtained in good yield by the reaction of ReNCl2(PMePh)3 with ReCl4(NCEt)2. It crystallizes in the triclinic space group P1 with a = 1037.7(3), b = 1153.0(2), c = 1393.8(3) pm, α = 72.31(2)°, β = 74.06(2)°, γ = 67.94(2)°, and Z = 1. The bond lengths of the Re–N triple bonds are 172 pm in 1 and 170 pm in 1 · 2 SbCl3. By the reaction of ReNCl2(PMePh)3 with SbCl5 in CH2Cl2 the solvent is decomposed forming HCl which protonates the nitrido ligand to afford the imido complex [Re(NH)Cl2(PMe2Ph)3][SbCl6] ( 2 ) crystallizing in the monoclinic space group P21/n with a = 1221.4(2), b = 1358.6(2), c = 2177.3(1) pm, β = 92,72(1)° and Z = 4. The Re–N distance in the almost linear unit Re≡N–H is 169,1 pm. 相似文献
255.
The reaction of CpMo(CO)3X (X = Cl, I) with SbF5 in toluene leads to the cationic, halogen bridged compounds [{CpMo(CO)3}2X]SbF6 ( 1 , 2 ). CpW(CO)3Cl reacts with SbF5 to yield [{CpW(CO)3}2Cl]SbF6 ( 3 ), whereas with SbCl5, the oxidative substitution product [{CpW(CO)2Cl2}2Cl]SbCl6 ( 4 ) is formed, which decomposes in solution to yield the trichloride CpW(CO)2Cl3 ( 5 ). The strong Lewis acid SbF5 separates the halide from CpM(CO)3X (M = Mo, W), and the resulting cationic fragment “CpM(CO)3+” reacts with a further CpM(CO)3X forming a halonium bridge ( 1 – 3 ). The exclusive formation of SbF6– can be explained by the oxidizing power of SbF5. The IR, MS and NMR spectra of the compounds 1 – 5 as well as the X‐ray structure analysis of 5 are reported and discussed. 相似文献
256.
The protein sequence of the hyoscyamine 6β-hydroxylase gene from Hyoscyamusniger was analysed in silico for its potential of heterologous expression. Therefore different parameters determining the proteins properties and structure in prokaryotic or eukaryotic protein expression systems were taken into account. In silico prediction of co- and post-translational modifications revealed 25 putative glycosylation sites, one of which reported to be a co-factor stabilizing residue in 2-oxoglutarate dependent dioxygenases. Potential protein solubility and degradation (PEST) motifs were also evaluated. Together with the calculated physico-chemical properties the results indicated reasonable solubility but potential instability of the protein in Escherichia coli and Saccharomyces cerevisiae. Further a synthetic h6h-gene was introduced into the prokaryotic or eukaryotic hostsEscherichia coli and Saccharomyces cerevisiae to determine protein expression. The protein could be expressed in both organisms, though stability was confirmed to be an issue. 相似文献
257.
In this work, we present an extension of the forward–reverse representation introduced by Bayer and Schoenmakers (Annals of Applied Probability, 24(5):1994–2032, 2014) to the context of stochastic reaction networks (SRNs). We apply this stochastic representation to the computation of efficient approximations of expected values of functionals of SRN bridges, that is, SRNs conditional on their values in the extremes of given time intervals. We then employ this SRN bridge-generation technique to the statistical inference problem of approximating reaction propensities based on discretely observed data. To this end, we introduce a two-phase iterative inference method in which, during phase I, we solve a set of deterministic optimization problems where the SRNs are replaced by their reaction-rate ordinary differential equations approximation; then, during phase II, we apply the Monte Carlo version of the expectation-maximization algorithm to the phase I output. By selecting a set of overdispersed seeds as initial points in phase I, the output of parallel runs from our two-phase method is a cluster of approximate maximum likelihood estimates. Our results are supported by numerical examples. 相似文献
258.
Dinuclear Cobalt Complexes with a Decadentate Ligand Scaffold: Hydrogen Evolution and Oxygen Reduction Catalysis
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Dr. Carlo Di Giovanni Dr. Carolina Gimbert‐Suriñach Dr. Michael Nippe Dr. Jordi Benet‐Buchholz Prof. Jeffrey R. Long Dr. Xavier Sala Prof. Antoni Llobet 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(1):361-369
A new decadentate dinucleating ligand containing a pyridazine bridging group and pyridylic arms has been synthesized and characterized by analytical and spectroscopic techniques. Four new dinuclear cobalt complexes featuring this ligand have been prepared and thoroughly characterized both in the solid state (X‐ray diffraction) and in solution (1D and 2D NMR spectroscopy, ESI‐MS, and electrochemical techniques). The flexible but stable coordination environment provided by the ligand scaffold when coordinating Co in different oxidation states is shown to play a crucial role in the performance of the set of complexes when tested as catalysts for the photochemical hydrogen evolution reaction (HER) and chemical oxygen reduction reaction (ORR). 相似文献
259.
用多微段变刚度杆单元分析钢筋混凝土斜拉桥的非线性地震响应 总被引:2,自引:0,他引:2
预先确定斜拉桥的弹塑性区域,把包含多微段平面变刚度梁单元推广应用于大跨度斜拉桥的非线性地震响应分析,用微段的刚度变化模拟钢筋混凝土的弹塑性性能,对双塔单索面钢筋混凝土斜拉桥进行了考虑几何非线性和材料非线性的地震响应分析,编制了相应的弹塑性分析程序,并与Huges单元分析结果进行了比较。结果表明:本文方法能较好地模拟在强震作用下钢筋混凝土斜拉桥的非线性性能,可以在大跨斜拉桥的非线性地震响应分析中应用。 相似文献
260.