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91.
C. Jandl S. Stegbauer A. Pthig 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(7):509-513
In the coordination chemistry of palladium, dimers bridged via halides are a common motif. Higher oligomers, however, are still rare. We report the structure of an alternating eight‐membered [Pd4Br4]4− ring framed by cycloheptatrienide ligands, which was obtained by cocrystallization of dimers and tetramers of the complex salt bromido{η3‐[3‐(2,6‐diisopropylphenyl)imidazolium‐1‐yl]cycloheptatrienido}palladium(II) tetrafluoroborate, namely bis[di‐μ‐bromido‐bis({η3‐[3‐(2,6‐diisopropylphenyl)imidazolium‐1‐yl]cycloheptatrienido}palladium(II))] cyclo‐tetra‐μ‐bromido‐tetrakis({η3‐[3‐(2,6‐diisopropylphenyl)imidazolium‐1‐yl]cycloheptatrienido}palladium(II)) octakis(tetrafluoroborate) dichloromethane octasolvate, [Pd4Br4(C22H26N2)4][Pd2Br2(C22H26N2)2]2(BF4)8·8CH2Cl2. These dimers and tetramers form a highly dynamic equilibrium in solution which was studied by low‐temperature NMR spectroscopy. In the light of the presented results, tetrameric PdII species can be assumed to co‐exist as a second species in many cases where by current knowledge only a dimeric compound would be expected. 相似文献
92.
93.
Two-Photon-Induced CO-Releasing Molecules as Molecular Logic Systems in Solution,Polymers, and Cells
Dr. Vadde Ramu Dr. Gandra Upendar Reddy Dr. Jingjing Liu Patrick Hoffmann Dr. Rudrakant Sollapur Dr. Ralf Wyrwa Dr. Stephan Kupfer Prof. Dr. Christian Spielmann Dr. Sylvestre Bonnet Prof. Dr. Ute Neugebauer Dr. Alexander Schiller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(36):8453-8458
Phototherapeutic applications of carbon monoxide (CO)-releasing molecules are limited because they require harmful UV and blue light for activation. We describe two-photon excitation with NIR light (800 nm)-induced CO-release from two MnI tricarbonyl complexes bearing 1,8-naphthalimide units ( 1 , 2 ). Complex 2 behaves as a logic OR gate in solution, nonwovens, and in HeLa cells. CO release, indicated by fluorescence enhancement, was detected in solution, nonwoven, and HeLa cells by single- (405 nm) and two-photon (800 nm) excitation. The photophysical properties of 1 and 2 have been measured and supported by DFT and TDDFT quantum chemical calculations. Both photoCORMs are stable in the dark in solution and noncytotoxic, leading to promising applications as phototherapeutics with NIR light. 相似文献
94.
Caterina Calgaro Claire Colin Emmanuel Creus Ezzeddine Zahrouni 《Mathematical Methods in the Applied Sciences》2019,42(1):250-271
In this work, we prove the existence and the uniqueness of the strong solution of a low‐Mach model, for which the dynamic viscosity of the fluid is a given function of its temperature. The method is based on the convergence study of a sequence towards the solution, for which the rates are also given. The originality of the approach is to consider the system in terms of the temperature and the velocity, leading to a nonlinear temperature equation and the development of some specific tools and results. 相似文献
95.
S. Shanmuganathan D. L. Youngs J. Griffond B. Thornber R. J. R. Williams 《国际流体数值方法杂志》2014,74(5):335-358
At low Mach numbers, Godunov‐type approaches, based on the method of lines, suffer from an accuracy problem. This paper shows the importance of using the low Mach number correction in Godunov‐type methods for simulations involving low Mach numbers by utilising a new, well‐posed, two‐dimensional, two‐mode Kelvin–Helmholtz test case. Four independent codes have been used, enabling the examination of several numerical schemes. The second‐order and fifth‐order accurate Godunov‐type methods show that the vortex‐pairing process can be captured on a low resolution with the low Mach number correction applied down to 0.002. The results are compared without the low Mach number correction and also three other methods, a Lagrange‐remap method, a fifth‐order accurate in space and time finite difference type method based on the wave propagation algorithm, and fifth‐order spatial and third‐order temporal accurate finite volume Monotone Upwind Scheme for Conservation Laws (MUSCL) approach based on the Godunov method and Simple Low Dissipation Advection Upstream Splitting Method (SLAU) numerical flux with low Mach capture property. The ability of the compressible flow solver of the commercial software, ANSYS FLUENT , in solving low Mach flows is also demonstrated for the two time‐stepping methods provided in the compressible flow solver, implicit and explicit. Results demonstrate clearly that a low Mach correction is required for all algorithms except the Lagrange‐remap approach, where dissipation is independent of Mach number. © 2013 Crown copyright. International Journal for Numerical Methods in Fluids. © 2013 John Wiley & Sons, Ltd. 相似文献
96.
Hsuan-Wei Lee Li-Ming Chang Ying-Ling Liu 《Journal of polymer science. Part A, Polymer chemistry》2021,59(17):1912-1918
Cyclic siloxane is an attractive building block for incorporation of silicon-containing units as well as their distinguished properties to polymer materials. This work reports the synthesis and characterization of a tetra-functional vinylbenzene compound possessing cyclic siloxane cores (cD4-4VB). Synthesis of cD4-4VB is carried out using cD4-4SiH as the reactive precursor and multiple-step reactions, including hydrosilylation, deacetylation, and SN2 substitution. cD4-4VB is an effective monomer for preparation of the corresponding cyclic silicon-based thermosetting resins (CR-cD4-4VB). CR-cD4-4VB shows attractive film formability and good thermo-mechanical properties, including a storage modulus of 2.0 GPa, a glass transition temperature of 282°C, a thermal stability above 400°C, a high char yield (at 800°C in nitrogen) of 55 wt%, and a dielectric constant of 3.12 at 10 GHz. This kind of resins have potential of application for halogen-free flame retardants and high-performance polymer films. 相似文献
97.
Yingjie Zhang Ping Ning Xueqian Wang Langlang Wang Yixing Ma Qiang Ma Yibing Xie 《应用有机金属化学》2019,33(6)
Manganese‐ and cerium oxide‐modified titania catalysts were prepared by the deposition precipitation for the removal of elemental mercury (Hg0) from simulated yellow phosphorus off‐gas at low temperature. In addition, these catalysts were characterized by X‐ray diffraction, Brunauer–Emmett–Teller measurements, X‐ray photoelectron spectroscopy and field‐emission scanning electron microscope to determine the surface morphology of the obtained compounds and explore their formation mechanism. The results revealed that a Mn–Ce loading and reaction temperature of 10% and 150 °C, respectively, as well as a Mn/Ce molar ratio of 2:1, led to an optimal efficiency for the oxidation of elemental mercury. Furthermore, the effects of flue gas components were investigated. The presence of O2 clearly promoted the oxidation of Hg0. A CO atmosphere did not affect the Hg0 oxidation, when compared with N2, whereas the presence of H2S and water vapor inhibited the oxidation process. Furthermore, the X‐ray photoelectron spectroscopy spectra of Hg 4f revealed that the elemental mercury adsorbed by the catalyst is present as HgO. Finally, the Hg0 catalytic oxidation mechanism was discussed on the basis of the experimental results and characterization analysis. 相似文献
98.
Dr. Tao Yang Prof. Yan Song Dr. Xiaodong Tian Prof. Huaihe Song Prof. Zhanjun Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(69):16514-16520
Pitch has been used to prepare electrodes by high-temperature heat treatments for supercapacitors, lithium-ion batteries, on account of its rich aromatic ring structure. Here, the toluene-soluble component of pitch is used to prepare a kind of laminated carbon. This was realized by a template-free synthesis at low temperature with the addition of pressure. The toluene-soluble component has a small molecular weight, which makes the thermal deformation ability stronger and then enhances the orientation of the carbon layer with the help of pressure. The prepared anode exhibits a splendid electrochemical performance compared with the traditional graphite anode. A high stable capacity of approximately 550 mAh g−1 at 50 mA g−1, which is much higher than graphite (372 mAh g−1), is obtained. Also, when the current density is up to 2 A g−1, the capacity is about 150 mAh g−1. Surprisingly, it also delivers a superior cycling performance. And when used as the anode/cathode electrode for lithium-ion capacitors, a high energy density can be obtained. The present work offers an opportunity to utilize the pitch source in lithium energy storage with promising cycle life, high energy/power density, and low cost. 相似文献
99.
As Reduced Activation Ferritic/Martensitic (RAFM) steel is considered the primary candidate for use as a structural material in fusion power reactors,many countries are developing different kinds of RAFM.China is developing new CLAM (China Low Activation Martensitic) steel.The study investigates microstructural changes in CLAM steel implanted with deuterium ions induced by 1250 keV electron irradiation from R.T.to 873 K,and observes both the growth and shrinkage of the defect clusters produced by deuterium ... 相似文献
100.
Titanium tetrachloride in ethyl acetate can be reduced by Mg powder to the corresponding low‐valent titanium complexes, which can reduce some aromatic aldehydes and ketones to the corresponding pinacols in 38–85% yields within 15–60 min at rt with stirring. 相似文献